JP2016127697A - Motor control device and generator control device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a technique that is adaptable to startup and low-speed driving of a 3-phase motor.SOLUTION: Current sensors 105a, 105b generate a signal which is fed back from a 3-phase motor 102 and represents motor current flowing in the 3-phase motor 102. A phase identification part 111 identifies the phase of an instruction magnetic flux vector. An amplitude identification part 115 identifies the amplitude of the instruction magnetic flux vector. An instruction magnetic flux part 112 identifies an instruction magnetic flux vector by using the phase of the instruction magnetic flux vector identified by the phase identification part 111 and the amplitude of the instruction magnetic flux vector identified by the amplitude identification part 115. The amplitude identification part 115 has (i) a temporary setting part 130 for setting a temporary amplitude, (ii) an amplitude correction amount generator 114 for generating an amplitude correction amount by using a control target amount applied to the 3-phase motor 102 which is identified by using a signal, and (iii) a correction part 117 for identifying a correction amplitude larger than the temporary amplitude as an amplitude to be applied to the instruction magnetic flux identification part 112.SELECTED DRAWING: Figure 3

Description

  The present disclosure relates to a motor control device and a generator control device.

  As an example of a three-phase motor drive system, direct torque control (DTC) is known. In an example of direct torque control, first, a phase current and a phase voltage of a three-phase motor connected to an inverter are detected. Next, the armature linkage flux and motor torque of the three-phase motor are obtained from the phase current and phase voltage. Next, a command magnetic flux vector is obtained from the obtained torque, command torque, command amplitude, and armature flux linkage position. The command torque and the command amplitude are obtained by a speed control device, for example. Next, a voltage vector to be applied from the inverter to the three-phase motor is determined from the command magnetic flux vector and the armature linkage magnetic flux. Next, switching of the inverter is controlled so that the determined voltage vector is applied to the three-phase motor. The drive algorithm for direct torque control is simple. Further, position sensors such as encoders and resolvers can be omitted. Patent Document 1, Non-Patent Document 1, Non-Patent Document 2, and Non-Patent Document 3 describe techniques related to direct torque control.

  Various systems other than direct torque control are also known as driving systems for the three-phase motor. In many systems, including direct torque control, a voltage vector is applied to the three-phase motor using an inverter so that the motor magnetic flux of the three-phase motor follows the command magnetic flux vector. Such a system is sometimes called a magnetic flux control system.

Japanese Patent No. 4972135

Inoue and three others, “Torque ripple reduction, and flux-weakening control for interior permanent magnet synchronous motor based on direct torque control”, 2006 Proceedings of the IEEJ National Conference, IEEJ, March 2006, 4th volume, 4-106, p. 166-167 Togashi, three others, “Sensorless Starting Method for Ultra-High-Speed PMSM Drive Using Direct Torque Control”, Proceedings of 2013 Annual Conference of the Institute of Electrical Engineers of Japan , Institute of Electrical Engineers of Japan, March 2006, 4th volume, 4-106, p. 178 Kaku, and two others, “A Novel Technique for a DC Brushless Motor Having No Position Sensors”, Electron Theory D, Vol. 111-D, No. 8, pp. 639- 644 (1999)

  The conventional magnetic flux control method has room for improvement from the viewpoint of starting the three-phase motor and ensuring the stability of low-speed driving. Accordingly, an object of the present disclosure is to provide a technique suitable for starting and low-speed driving.

That is, this disclosure
A motor control device that applies a voltage vector to the three-phase motor using an inverter so that the motor magnetic flux of the three-phase motor follows a command magnetic flux vector,
A current sensor that generates a signal that is fed back from the three-phase motor and that represents a motor current flowing through the three-phase motor;
A phase specifying unit for specifying the phase of the command magnetic flux vector;
An amplitude specifying unit for specifying the amplitude of the command magnetic flux vector;
A command magnetic flux specifying unit for specifying the command magnetic flux vector using the phase of the command magnetic flux vector specified by the phase specifying unit and the amplitude of the command magnetic flux vector specified by the amplitude specifying unit; With
The amplitude specifying unit generates an amplitude correction amount using (i) a temporary setting unit for setting a temporary amplitude, and (ii) a control target amount applied to the three-phase motor specified using the signal. And (iii) a correction unit that specifies a correction amplitude larger than the temporary amplitude as the amplitude to be given to the command magnetic flux specifying unit using the amplitude correction amount. A control device is provided.

  The motor control device described above is suitable for starting and low-speed driving of a three-phase motor.

Block diagram of motor controller Diagram for explaining dq coordinate system and αβ coordinate system Block diagram of the motor control unit of the first embodiment Block diagram of an amplitude correction amount generation unit of the first embodiment The block diagram of the phase specific | specification part of 1st Embodiment Inverter configuration diagram Block diagram of motor control section of modification 1-1A Block diagram of torque estimation unit of modification 1-1A Block diagram of phase identification unit of modification 1-1A Block diagram of phase identification unit of modification 1-1B Block diagram of motor control section of modification 1-2A Block diagram of motor control unit of modification 1-2B Block diagram of modified amplitude amount generation unit of modification 1-2A Block diagram of modified amplitude amount generation unit of modification 1-2B The graph which shows the simulation result for demonstrating the effect of modification 1-2A The graph which shows the simulation result for demonstrating the effect of modification 1-2A The graph which shows the simulation result for demonstrating the effect of modification 1-2A Block diagram of motor control unit of modification 1-3 Block diagram of motor control unit of second embodiment The block diagram of the phase specific | specification part of 2nd Embodiment Block diagram of motor control unit of modification 2-1A Block diagram of phase specifying unit of modification 2-1A Block diagram of phase specifying unit of modification 2-1B Block diagram of motor controller of modification 2-2 Block diagram of motor controller of modification 2-3 Block diagram of motor control unit of third embodiment The block diagram of the phase specific | specification part of 3rd Embodiment Block diagram of motor control unit of modification 3-1

  A magnetic flux control system is known as a system for controlling a three-phase motor. In the magnetic flux control method, a voltage vector is applied to the three-phase motor using an inverter so that the motor magnetic flux of the three-phase motor follows the command magnetic flux vector.

  A voltage drop occurs in the semiconductor element in the inverter. This voltage drop makes the amplitude of the magnetic flux vector actually applied to the three-phase motor smaller than the amplitude of the command magnetic flux vector. The inverter is provided with a dead time. The dead time can also cause the amplitude of the magnetic flux vector actually applied to the three-phase motor to be smaller than the amplitude of the command magnetic flux vector. These errors become apparent when the induced voltage in the inverter is small, such as when the three-phase motor is started or driven at a low speed. For this reason, the amplitude of the voltage vector applied to the three-phase motor becomes insufficient at the time of start-up, low-speed driving, etc., and the torque tends to be insufficient. For this reason, it is not always easy to start the three-phase motor stably or to stably drive the three-phase motor at a low speed.

  Non-patent document 2 describes a technique for reducing the above-described error. In this technique, the amplitude of the command magnetic flux vector is set by feedforward so as to be inversely proportional to the speed of the three-phase motor. According to Non-Patent Document 2, this technique makes it possible to apply a voltage vector having a sufficiently large amplitude to the three-phase motor at the time of starting and at the time of low-speed driving, thereby facilitating the starting and low-speed driving of the three-phase motor.

  However, according to the study by the present inventors, even if the technique described in Non-Patent Document 2 is used, the starting and low-speed driving of the three-phase motor are not sufficiently stabilized. In this technology, the amplitude of the command magnetic flux vector is not set according to the operating environment of the three-phase motor, but only the command magnetic flux vector amplitude is set by feedforward. This is because an appropriate response cannot be made. In view of such circumstances, the present inventors have studied to provide a motor control device suitable for starting and low-speed driving of a three-phase motor.

That is, the first aspect of the present disclosure is:
A motor control device that applies a voltage vector to the three-phase motor using an inverter so that the motor magnetic flux of the three-phase motor follows a command magnetic flux vector,
A current sensor that generates a signal that is fed back from the three-phase motor and that represents a motor current flowing through the three-phase motor;
A phase specifying unit for specifying the phase of the command magnetic flux vector;
An amplitude specifying unit for specifying the amplitude of the command magnetic flux vector;
A command magnetic flux specifying unit for specifying the command magnetic flux vector using the phase of the command magnetic flux vector specified by the phase specifying unit and the amplitude of the command magnetic flux vector specified by the amplitude specifying unit; With
The amplitude specifying unit generates an amplitude correction amount using (i) a temporary setting unit for setting a temporary amplitude, and (ii) a control target amount applied to the three-phase motor specified using the signal. And (iii) a correction unit that specifies a correction amplitude larger than the temporary amplitude as the amplitude to be given to the command magnetic flux specifying unit using the amplitude correction amount. A control device is provided.

  Appropriate operating conditions for the three-phase motor depend on the operating environment of the three-phase motor. Therefore, even if a temporary amplitude suitable for a certain driving environment is set, the temporary amplitude is not always appropriate in another driving environment. For this reason, if the set temporary amplitude is directly applied to the command magnetic flux specifying unit, the torque may be insufficient. Such a torque shortage is likely to occur when the three-phase motor is started and when it is driven at a low speed. In this regard, the amplitude specifying unit of the first aspect is configured such that a correction amplitude larger than the temporary amplitude is specified. This makes it difficult to cause torque shortage. Furthermore, according to the first aspect, the control target amount is specified using the signal fed back from the three-phase motor, and the correction amplitude is specified using the control target amount. That is, the signal fed back from the three-phase motor is reflected in the amplitude of the command magnetic flux vector. This enables operation according to the operation environment of the three-phase motor. For the above reasons, the motor control device of the first aspect is suitable for starting and low-speed driving of a three-phase motor.

The second aspect of the present disclosure includes, in addition to the first aspect,
The control target amount provides a motor control device having an amplitude of a motor current flowing through the three-phase motor.

The third aspect of the present disclosure includes, in addition to the first aspect,
The control target amount provides a motor control device that is reactive power applied to the three-phase motor.

The fourth aspect of the present disclosure includes, in addition to the third aspect,
The amplitude correction amount generation unit specifies (a) a first inner product of a motor current flowing through the three-phase motor and the motor magnetic flux, and the speed of the three-phase motor estimated to the specified first inner product. Alternatively, the reactive power is specified by multiplying by the command speed, or (b) an axial current that represents the motor current flowing through the three-phase motor by two-phase coordinates and the three-phase motor. There is provided a motor control device that specifies the reactive power using an axial voltage that represents the voltage vector by the two-phase coordinates.

The fifth aspect of the present disclosure includes, in addition to the first aspect,
The control target amount provides a motor control device that is a physical quantity correlated with reactive power applied to the three-phase motor.

The sixth aspect of the present disclosure includes, in addition to the fifth aspect,
The amplitude correction amount generation unit specifies a first inner product of a motor current flowing through the three-phase motor and the motor magnetic flux, and specifies the physical quantity using the specified first inner product. provide.

The seventh aspect of the present disclosure includes, in addition to the fifth aspect,
The amplitude correction amount generation unit specifies a second inner product of a motor current flowing through the three-phase motor and a magnet magnetic flux of a permanent magnet of the three-phase motor, and uses the specified second inner product as the physical quantity. A motor control device is provided.

The eighth aspect of the present disclosure includes, in addition to the second aspect, the third aspect, the fourth aspect, or the seventh aspect,
The amplitude correction amount generation unit provides a motor control device that specifies the amplitude correction amount so that the specified control target amount is positive.

  The motor control devices of the second to eighth aspects can be configured simply. Further, specifying the amplitude correction amount so that the control target amount in the eighth mode is positive means that a motor current having a larger amplitude than that when MTPA is established flows to the three-phase motor, and torque This contributes to prevention of shortage and is convenient for starting and low-speed driving of a three-phase motor. The MTPA control is an abbreviation for maximum torque / current control, and is control for generating the maximum torque with the minimum current. For details of MTPA control, publicly known documents (Yoji Takeda, Shigeo Morimoto, Nobuyuki Matsui, Yukio Honda, “Design and Control of Embedded Magnet Synchronous Motor”, Ohm Co., Ltd., issued on October 25, 2001, etc.) Please refer to.

The ninth aspect of the present disclosure is in addition to any one of the first to eighth aspects,
The amplitude correction amount generation unit provides a motor control device that generates the amplitude correction amount by feedback control that converges a deviation between the control target amount and a target value to zero.

In a tenth aspect of the present disclosure, in addition to the ninth aspect,
The amplitude correction amount generation unit specifies the larger amplitude correction amount as the deviation obtained by subtracting the control target amount from the target value is larger,
The correction unit provides a motor control device that specifies the larger correction amplitude as the amplitude correction amount is larger.

  According to the ninth aspect and the tenth aspect, the control target amount can be made to follow the target value. As a result, the physical quantity of the three-phase motor other than the control target quantity is also controlled to some extent. Therefore, according to the ninth aspect and the tenth aspect, an appropriate torque can be ensured through control of the control target amount.

In an eleventh aspect of the present disclosure, in addition to any one of the first to tenth aspects,
The phase specifying unit specifies a moving amount for each control cycle in which the phase of the motor magnetic flux should move using the command speed, and specifies the phase of the command magnetic flux vector using the specified moving amount. A motor control device is provided.

  The phase specifying unit of the eleventh aspect can be configured simply.

The twelfth aspect of the present disclosure includes, in addition to the eleventh aspect,
The phase specifying unit provides a motor control device that specifies the phase of the command magnetic flux vector by integrating the movement amount.

  According to the twelfth aspect, the phase of the command magnetic flux vector can be easily specified. According to the twelfth aspect, the phase of the command magnetic flux vector can be specified by feedforward control. This leads to a reduction in calculation load of the motor control device.

The thirteenth aspect of the present disclosure, in addition to the eleventh aspect,
The motor control device
A shaft current representing the motor current flowing through the three-phase motor in two-phase coordinates, and a shaft voltage representing the voltage vector to be applied to the three-phase motor in the two-phase coordinates; , And a motor magnetic flux estimator for estimating the motor magnetic flux applied to the three-phase motor,
A phase estimation unit that estimates the phase of the motor magnetic flux using the motor magnetic flux estimated by the motor magnetic flux estimation unit;
The phase identification unit provides a motor control device that identifies the phase of the command magnetic flux vector using the phase of the motor magnetic flux estimated by the phase estimation unit and the movement amount.

  According to the thirteenth aspect, the phase of the command magnetic flux vector can be easily specified. In the thirteenth aspect, the motor magnetic flux estimated for specifying the phase of the command magnetic flux vector is used, and the axial current is used for the estimation. This means that the motor current information is reflected in the specification of the phase of the command magnetic flux vector, which contributes to the proper setting of the phase of the command magnetic flux vector and stabilizes the start and low-speed driving of the three-phase motor. It helps to make it.

The fourteenth aspect of the present disclosure is in addition to any one of the eleventh to thirteenth aspects,
The phase specifying unit (p) corrects the command speed using the estimated vibration component of the motor torque, specifies the movement amount using the corrected command speed, and determines the specified movement amount. (Q) identifying the amount of movement using the command speed, correcting the identified amount of movement using a vibration component of the estimated motor torque, The phase of the command magnetic flux vector is specified using the corrected amount of movement, or (r) the amount of movement is specified using the command speed, and the command magnetic flux vector is used using the specified amount of movement. A motor control device is provided that identifies the phase of the motor and corrects the identified phase using a stationary component of the estimated motor torque.

  According to the fourteenth aspect, the vibration component or steady component information of the motor torque is reflected when the phase of the command magnetic flux vector is specified. This helps to stabilize the starting and low speed driving of the three-phase motor.

The fifteenth aspect of the present disclosure is in addition to any one of the first to tenth aspects,
The motor control device
Applying the voltage vector to the three-phase motor using the inverter so that the motor magnetic flux and the motor torque of the three-phase motor follow the command magnetic flux vector and the command torque;
A shaft current representing the motor current flowing through the three-phase motor in two-phase coordinates, and a shaft voltage representing the voltage vector to be applied to the three-phase motor in the two-phase coordinates; , And a motor magnetic flux estimator for estimating the motor magnetic flux applied to the three-phase motor,
A torque estimator for estimating the motor torque from the shaft current and the estimated motor magnetic flux;
A speed estimator for estimating the speed of the three-phase motor from the estimated phase of the motor magnetic flux;
A command torque generator for generating the command torque from the command speed and the estimated speed,
The phase specifying unit specifies a moving amount for each control cycle in which the phase of the motor magnetic flux should move using a torque deviation between the command torque and the estimated motor torque, and the specified moving amount And a motor control device that identifies the phase of the command magnetic flux vector using the estimated phase of the motor magnetic flux.

  The motor control device of the fifteenth aspect can be configured simply.

The sixteenth aspect of the present disclosure includes
A generator control device that applies a voltage vector to the three-phase generator using a converter so that the generator magnetic flux of the three-phase generator follows a command magnetic flux vector,
A current sensor for generating a signal fed back from the three-phase generator and representing a generator current flowing through the three-phase generator;
A phase specifying unit for specifying the phase of the command magnetic flux vector;
An amplitude specifying unit for specifying the amplitude of the command magnetic flux vector;
A command magnetic flux specifying unit for specifying the command magnetic flux vector using the phase of the command magnetic flux vector specified by the phase specifying unit and the amplitude of the command magnetic flux vector specified by the amplitude specifying unit; With
The amplitude specifying unit includes: (i) a temporary setting unit for setting a temporary amplitude; and (ii) an amplitude correction amount using a control target amount applied to the three-phase generator specified using the signal. An amplitude correction amount generation unit to generate, and (iii) a correction unit that specifies a correction amplitude larger than the temporary amplitude as the amplitude to be given to the command magnetic flux specifying unit using the amplitude correction amount, A generator control device is provided.

A seventeenth aspect of the present disclosure includes
A motor control method for applying a voltage vector to the three-phase motor using an inverter so that the motor magnetic flux of the three-phase motor follows a command magnetic flux vector,
Generating a signal fed back from the three-phase motor and representing a motor current flowing through the three-phase motor;
Identifying the phase of the command magnetic flux vector;
Identifying the amplitude of the command magnetic flux vector;
Identifying the command magnetic flux vector using the phase of the identified command magnetic flux vector and the amplitude of the identified command magnetic flux vector,
The step of specifying the amplitude includes: (i) setting a temporary amplitude; and (ii) generating an amplitude correction amount using the control target amount applied to the three-phase motor specified using the signal. And (iii) specifying a correction amplitude larger than the provisional amplitude as the amplitude to be used in the step of specifying the command magnetic flux vector using the amplitude correction amount. I will provide a.

According to an eighteenth aspect of the present disclosure,
A generator control method of applying a voltage vector to the three-phase generator using a converter so that a generator magnetic flux of the three-phase generator follows a command magnetic flux vector,
Generating a signal fed back from the three-phase generator and representing a generator current flowing through the three-phase generator;
Identifying the phase of the command magnetic flux vector;
Identifying the amplitude of the command magnetic flux vector;
Identifying the command magnetic flux vector using the phase of the identified command magnetic flux vector and the amplitude of the identified command magnetic flux vector,
The step of specifying the amplitude includes (i) a step of setting a temporary amplitude, and (ii) an amplitude correction amount using a control target amount applied to the three-phase generator specified using the signal. And (iii) specifying a correction amplitude larger than the provisional amplitude as the amplitude to be used in the step of specifying the command magnetic flux vector using the amplitude correction amount. Provide a control method.

  According to the sixteenth to eighteenth aspects, the same effect as that of the first aspect can be obtained.

  The technology related to the motor control device can be applied to the generator control device. The technology related to the generator control device can be applied to the motor control device. This is because the control mode is very similar in both cases. There is a difference between the motor and the generator such that the phase of the current flowing through the motor / generator is reversed, but those skilled in the art can configure both control devices in consideration of these differences.

  The technology related to the motor control device and the generator control device can be applied to the motor control method and the generator control method. The technology related to the motor control method and the generator control method can be applied to the motor control device and the generator control device.

  Hereinafter, embodiments and modifications of the present disclosure will be described in detail based on the drawings. Unless otherwise specified, the following description relates to starting of the three-phase motor and low-speed driving.

(First embodiment)
As shown in FIG. 1, the motor control device 100 includes a first current sensor 105a, a second current sensor 105b, a motor control unit 103, and a duty generation unit 101. Motor control device 100 is connected to inverter 104 and three-phase motor 102.

  The motor control unit 103 is configured to execute position sensorless operation of the three-phase motor 102. The position sensorless operation is an operation that does not use a position sensor such as an encoder or a resolver. In the position sensorless operation of the present embodiment, the phase of the motor magnetic flux is specified using the command speed, and the motor magnetic flux is controlled using the phase. The motor magnetic flux is a concept including both the armature linkage magnetic flux on the three-phase AC coordinates applied to the three-phase motor 102 and the magnetic flux obtained by coordinate conversion of the armature linkage flux. In this specification, “amplitude” may simply refer to magnitude (absolute value). Further, unless otherwise specified, “speed” represents the angular speed (unit: rad / s) of the rotor of the three-phase motor 102.

  The motor control device 100 may include elements provided by a control application executed in a DSP (Digital Signal Processor) or a microcomputer. The DSP or microcomputer may include peripheral devices such as a core, a memory, an A / D conversion circuit, and a communication port. Further, the motor control device 100 may include an element configured by a logic circuit.

(Outline of control using the motor control device 100)
An overview of control using the motor control device 100 will be described with reference to FIG. The phase currents i _u and i _w are detected by the current sensors 105a and 105b. The motor control unit 103 generates command voltage vectors v _u ^* , v _v ^* , v _w ^* from the command speed ω _ref ^* and the phase currents i _u , i _w . Each component of the command voltage vectors v _u ^* , v _v ^* , v _w ^* corresponds to a U-phase voltage, a V-phase voltage, and a W-phase voltage on a three-phase AC coordinate, respectively. The duty generation unit 101, the command voltage vector _{v u} ^*, v v ^*, the v _w ^*, the duty D _u, D _v, D _w is generated. The inverter 104 generates voltage vectors v _u , v _v , v _w to be applied to the three-phase motor 102 from the duties D _u , D _v , D _w . The command speed ω _ref ^* is given to the motor control device 100 from the host control device. The command speed ω _ref ^* represents the speed that the speed of the three-phase motor 102 should follow. With such control, the three-phase motor 102 is controlled such that the speed follows the command speed ω _ref ^* .

  Hereinafter, the motor control device 100 may be described based on α-β coordinates (two-phase coordinates). FIG. 2 shows α-β coordinates, UVW coordinates, and dq coordinates. The α-β coordinates are fixed coordinates. The α-β coordinates are also referred to as stationary coordinates and AC coordinates. The α axis is set as an axis extending in the same direction as the U axis. The d axis is defined as an axis that coincides with the rotor of the rotor, and its position is defined by θ. A position advanced 90 degrees from the d axis is defined as the q axis.

(About the motor control unit 103)
As shown in FIG. 3, the motor control unit 103 includes a u, w / α, β conversion unit (three-phase two-phase coordinate conversion unit) 106, a command voltage calculation unit 107, a motor magnetic flux estimation unit 108, a phase identification unit 111, Amplitude specifying unit 115, command magnetic flux specifying unit 112, α-axis magnetic flux deviation calculating unit 113a, β-axis magnetic flux deviation calculating unit 113b, α, β / u, v, w converting unit (two-phase three-phase coordinate converting unit) 109 are included. It is out.

In the motor control unit 103, the u, w / α, β conversion unit 106 converts the phase currents i _u , i _w into shaft currents i _α , i _β . The axial currents i _α and i _β are collectively described as the α-axis current i _α and the β-axis current i _β on the α-β coordinate of the three-phase motor 102. The motor magnetic flux estimator 108 estimates the motor magnetic flux from the shaft currents i _α and i _β and the shaft voltages (command shaft voltages) v _α ^* and v _β ^* (estimated magnetic flux Ψ _s is obtained). The α-axis component and β-axis component of the estimated magnetic flux ψ _s are described as estimated magnetic fluxes ψ _α and ψ _β , respectively. The phase identification unit 111 identifies the phase θ _s ^* of the command magnetic flux vector from the command speed ω _ref ^* . The amplitude specifying unit 115 determines the amplitude | Ψ _s ^** | of the command magnetic flux vector from the axial currents i _α and i _β . The command magnetic flux specifying unit 112 obtains the command magnetic flux vector ψ _s ^* from the amplitude | ψ _s ^** | and the phase θ _s ^* . The α-axis component and β-axis component of the command magnetic flux vector ψ _s ^* are described as α-axis command magnetic flux ψ _α ^* and β-axis command magnetic flux ψ _β ^* , respectively. the alpha-axis magnetic flux deviation calculation unit 113a, alpha axis command flux [psi _alpha ^* and the estimated flux [psi _alpha and deviation (the magnetic flux deviation) [Delta] [Psi] _alpha is obtained. the beta-axis magnetic flux deviation calculation unit 113b, beta axis command flux [psi _beta ^* and the estimated flux [psi _beta and deviation (the magnetic flux deviation) [Delta] [Psi] _beta is obtained. The command voltage calculation unit 107 determines the shaft voltages v _α ^* and v _β ^* from the magnetic flux deviations ΔΨ _α and ΔΨ _β and the shaft currents i _α and i _β . The axial voltages v _α ^* and v _β ^* collectively describe the α-axis command voltage v _α ^* and the β-axis command voltage v _β ^* on the α-β coordinate of the three-phase motor 102. The α, β / u, v, w conversion unit 109 converts the shaft voltages v _α ^* , v _β ^* into command voltage vectors v _u ^* , v _v ^* , v _w ^* .

By such control, the voltage vector is supplied to the three-phase motor 102 via the inverter 104 so that the speed of the three-phase motor 102 follows the command speed ω _ref ^* and the motor magnetic flux follows the command magnetic flux vector Ψ _s ^*. Applied.

In the present specification, the shaft currents i _α and i _β mean current values transmitted as information, not currents actually flowing through the three-phase motor 102. The same applies to the shaft voltages v _α ^* , v _β ^* , the estimated magnetic flux ψ _s , the command speed ω _ref ^* , the command magnetic flux vector ψ _s ^* , the command voltage vectors v _u ^* , v _v ^* , v _w ^{*, and the} like.

  Each component regarding control of this embodiment is explained below.

(First current sensor 105a, second current sensor 105b)
In the present embodiment, current sensors 105 a and 105 b are used as sensors that generate signals fed back from the three-phase motor 102. That is, the signal is a signal representing the current flowing through the three-phase motor 102. As shown in FIG. 1, the first current sensor 105a is provided to measure a phase current i _u flowing through the u phase. The second current sensor 105b is provided to measure the phase current i _w flowing through the w phase. However, the first current sensor 105a and the second current sensor 105b may be provided so as to measure a two-phase current of a combination other than the u-phase and w-phase two phases. Specific examples of the current sensors 105a and 105b are a current transformer and a shunt resistor.

(U, w / α, β converter 106)
The u, w / α, β converter 106 shown in FIG. 3 converts the phase currents i _u , i _w into axial currents i _α , i _β . Specifically, the u, w / α, β conversion unit 106 converts the phase currents i _u , i _w into the axial currents i _α , i _β by the equations (1) and (2), and the axial current i _α. , I _β .

(Motor magnetic flux estimation unit 108)
The motor magnetic flux estimation unit 108 obtains an estimated magnetic flux ψ _s (estimated magnetic flux ψ _α , ψ _β ) from the axial currents i _α and i _β and the axial voltages v _α ^* and v _β ^* . Specifically, the motor magnetic flux estimation unit 108 obtains the estimated magnetic fluxes Ψ _α and Ψ _β using the equations (3) and (4). In equations (3) and (4), ψ _{α | t = 0} and ψ _{β | t = 0} are initial values of the estimated magnetic fluxes ψ _α and ψ _β , respectively. R in equations (3) and (4) is the winding resistance of the three-phase motor 102. The motor magnetic flux estimating unit 108 may be a complete integrator or an incomplete integrator. When the motor magnetic flux estimator 108 is incorporated in a digital control device such as a DSP or a microcomputer, the integrator required for the calculations in the equations (3) and (4) can be configured as a discrete system. In a typical example in this case, a value derived from the current control period is added to or subtracted from the estimated magnetic fluxes Ψ _α , Ψ _β before one control period.

(Amplitude specifying unit 115)
The amplitude specifying unit 115 specifies the correction amplitude | ψ _s ^** | as the amplitude to be given to the command magnetic flux specifying unit 112 from the axial currents i _α and i _β . The amplitude specifying unit 115 includes a temporary setting unit 130, an amplitude correction amount generating unit 114, and a command magnetic flux adding unit 117.

(Temporary setting unit 130)
In the temporary setting unit 130, the temporary amplitude | Ψ _s ^* | of the command magnetic flux vector Ψ _s ^* is set. The amplitude of the command magnetic flux vector Ψ _s ^* has an optimum value according to the purpose of control during steady operation (such as MTPA). In one example, the provisional amplitude | Ψ _s ^* | is set to the same level as the optimum value. The optimal value can be ascertained through prior measurements. Specifically, the operation point may be known, for example, the motor torque is uniquely determined with respect to the speed of the three-phase motor 102. Although details are omitted, in such a case, the relationship between the speed of the three-phase motor 102 and the amplitude of the command magnetic flux vector Ψ _s ^* for obtaining the speed is generally known. Therefore, the amplitude specifying unit 115 can be configured to output the amplitude as the provisional amplitude | Ψ _s ^* |. Specifically, as the amplitude specifying unit 115, an approximate expression or a lookup table that specifies the temporary amplitude | Ψ _s ^* | from the command speed ω _ref ^* can be used. It is also possible to grasp the relationship between the speed of the three-phase motor 102 and the motor torque through prior measurement or the like. In this way, a similar approximate expression or lookup table can be provided. However, since the temporary amplitude | Ψ _s ^* | can be corrected by the command magnetic flux adding unit 117 during steady operation of the three-phase motor 102, the temporary amplitude | Ψ _s ^* | may be a constant. Specifically, the provisional amplitude | Ψ _s ^* | may be the magnetic flux parameter Ψ _a . The magnetic flux parameter Ψ _a is a constant (motor parameter) given as the amplitude of the magnetic flux generated by the permanent magnet in the three-phase motor 102. The temporary amplitude | Ψ _s ^* | is corrected to a correction amplitude | Ψ _s ^** | larger than the temporary amplitude | Ψ _s ^* | by the command magnetic flux adding unit 117 when the three-phase motor 102 is started and driven at a low speed. .

(Amplitude correction amount generator 114)
The amplitude correction amount generation unit 114 specifies the amplitude correction amount ΔΨ from the axial currents i _α and i _β . As illustrated in FIG. 4, the amplitude correction amount generation unit 114 includes an armature current specifying unit 131, an armature current deviation calculation unit 118, and a PI compensation unit (PI controller) 119.

(Armature current specifying part 131)
The armature current specifying unit 131 specifies the armature current I _a from the axis currents i _α and i _β . Specifically, the armature current specifying unit 131 specifies the armature current I _a using Equation (5). Armature current I _a is a square sum root axis current i _alpha and axis current i _beta. The armature current I _a is the amplitude of the current (motor current) flowing through the three-phase motor 102.

(Armature current deviation calculation unit 118)
The armature current deviation calculation unit 118 calculates a deviation ΔI _a (= I _a ^* −I _a ) between the command armature current I _a ^* and the armature current I _a . A known operator can be used as the armature current deviation calculation unit 118. In the present embodiment, the command armature current I _a ^* is an arbitrary positive constant. Specifically, the command armature current I _a ^* is obtained when a motor current having a sufficiently large amplitude is applied to the three-phase motor 102 when the three-phase motor 102 is started and driven at a low speed. Applied and sufficient torque is applied. The command armature current I _a ^* can be set based on an empirical rule, set based on a motor parameter, or set through prior measurement according to the use of the three-phase motor 102 or the like. Typically, during steady operation, the command armature current I _a ^* is made smaller than at startup and during low-speed driving. Thereby, high-efficiency steady operation of the three-phase motor 102 becomes possible.

(PI compensation unit 119)
The PI compensation unit 119 acquires _a deviation ΔI _a (= I _a ^* −I _a ) between the command armature current I _a ^* and the armature current I _a, and an amplitude correction amount ΔΨ so that the deviation ΔI _a becomes zero. Is identified. Specifically, as shown in Expression (6), the amplitude correction amount ΔΨ is obtained by performing a proportional / integral calculation using the deviation ΔI _a as an input. K _p is a proportional gain. K _I is an integral gain. s is a Laplace operator.

As can be understood from the equation (6) and the command armature current I _a ^* being a positive value, in this embodiment, the armature current I _a specified by the armature current specifying unit 131 (control target) The amplitude correction amount ΔΨ is specified by the amplitude correction amount generation unit 114 so that (amount) becomes positive.

(Command magnetic flux adding unit 117)
Returning to FIG. 3, the command magnetic flux adding unit 117 specifies the corrected amplitude | Ψ _s ^** | from the temporary amplitude | Ψ _s ^* | and the amplitude correction amount ΔΨ. Specifically, the command magnetic flux adding unit 117 obtains the correction amplitude | Ψ _s ^** | using Expression (7). That is, the corrected amplitude | Ψ _s ^** | is the sum of the temporary amplitude | Ψ _s ^* | and the amplitude correction amount ΔΨ.

As described above, the amplitude specifying unit 115 includes (i) the temporary setting unit 130 for setting the temporary amplitude | Ψ _s ^* | and (ii) the three-phase specified using the signal fed back from the three-phase motor 102. An amplitude correction amount generation unit 114 that generates an amplitude correction amount ΔΨ using the control target amount applied to the motor 102, and (iii) an amplitude to be given to the command magnetic flux specifying unit 112 using the amplitude correction amount ΔΨ. And a correction unit (command magnetic flux addition unit 117) that specifies a correction amplitude | Ψ _s ^** | larger than the provisional amplitude | Ψ _s ^* |. According to this configuration, the motor magnetic flux Ψ _s is easily secured. That is, this configuration is suitable for preventing torque shortage. In this embodiment, it can be said that the amplitude correction amount generation unit 114 generates the amplitude correction amount by feedback control that converges the deviation between the control target amount and the target value to zero. In this embodiment, the amplitude (armature current I _a ) of the current flowing through the three-phase motor 102 is used as the control target amount, the command armature current I _a ^* is used as the target value, and the deviation ΔI _a (= I _a ^This is because the amplitude correction amount ΔΨ is specified by feedback control that makes ^* −I _a ) zero. In the present embodiment, through such feedback control, the amplitude correction amount generating unit 114, a target value (command armature current I _a ^*) control target amount from the deviation obtained by subtracting the (armature current I _a) is greater if it specified the greater the larger the amplitude correction amount [Delta] [Psi], the correction unit (command flux addition unit 117) is greater correction amplitude the greater the amplitude correction amount [Delta] [Psi] | specifying the | Ψ _s ^**.

(Phase identification unit 111)
The phase specifying unit 111 specifies the phase θ _s ^* of the command magnetic flux vector Ψ _s ^* from the command speed ω _ref ^* . Specifically, the phase identification unit 111 as shown in FIG. 5 has an integrator 116, obtains the command flux vector [psi _s ^* phase theta _s ^* by integrating the command speed omega _ref ^*. In the present embodiment, the phase specifying unit 111 is incorporated in a digital control device, and the integrator 116 is configured as a discrete system. Therefore, the phase specifying unit 111 of the present embodiment uses the command speed ω _ref ^* input to the phase specifying unit 111 to specify and specify the amount of movement for each control period in which the phase θ of the motor magnetic flux Ψ _s should move. It said to identify the command flux vector [psi _s ^* phase theta _s ^* using the movement amount that has been. Specifically, it can be said that the phase specifying unit 111 specifies the phase θ _s ^* of the command magnetic flux vector Ψ _s ^* by integrating the movement amount. Examples of the digital control device include a DSP and a microcomputer.

(Command magnetic flux specifying unit 112)
The command magnetic flux specifying unit 112 obtains a command magnetic flux vector ψ _s ^* (command magnetic flux ψ _α ^* , ψ _β ^* ) from the corrected amplitude | ψ _s ^** | and the phase θ _s ^* . Specifically, the command magnetic fluxes Ψ _α ^* and Ψ _β ^* are obtained using the equations (8) and (9).

(Α-axis magnetic flux deviation calculator 113a, β-axis magnetic flux deviation calculator 113b)
alpha -axis magnetic flux deviation calculation unit 113a obtains the command flux [psi _alpha ^* and the estimated flux [psi _alpha, these deviations (the magnetic flux deviation ^{_{ΔΨ α: Ψ α * -Ψ α}} ) obtained. The β-axis magnetic flux deviation calculation unit 113b acquires the command magnetic flux Ψ _β ^* and the estimated magnetic flux Ψ _β and obtains the deviation (magnetic flux deviation ΔΨ _β : Ψ _β ^* −Ψ _β ). As the magnetic flux deviation calculators 113a and 113b, known operators can be used.

(Command voltage calculation unit 107)
The command voltage calculation unit 107 obtains the axial voltages v _α ^* and v _β ^* from the magnetic flux deviations ΔΨ _α and ΔΨ _β and the axial currents i _α and i _β . Specifically, the command voltage calculation unit 107 obtains the α-axis command voltage v _α ^* using Expression (10). Moreover, the command voltage calculating part 107 calculates | requires (beta) -axis command voltage v ( _beta) ^* using Formula (11).

(Α, β / u, v, w converter 109)
The α, β / u, v, w conversion unit 109 converts the shaft voltages v _α ^* , v _β ^* into command voltage vectors v _u ^* , v _v ^* , v _w ^* . Specifically, the α, β / u, v, w conversion unit 109 converts the shaft voltages v _α ^* , v _β ^* into the command voltage vectors v _u ^* , v _v ^* , v _w ^{* according} to the equation (12). Then, the command voltage vectors v _u ^* , v _v ^* , v _w ^* are output.

(Duty generator 101)
Duty generation unit 101 shown in FIG. 1, the command voltage vector _{^{v u *, v v *,}} v from _w ^*, the duty D _u, D _v, to produce a D _w. In the present embodiment, the duty generation unit 101 converts each component of the command voltage vectors v _u ^* , v _v ^* , v _w ^* into the duties _Du , D _v , D _w of each phase. As a method for generating the duties D _u , D _v , and D _w, a method used for a general voltage source PWM inverter can be used. For example, the duty D _u, D _v, D _w is the command voltage vector _{v u} ^*, v v ^*, and v _w ^*, by dividing in half the value of the voltage value V _dc of the DC power supply 122 (FIG. 6) You may ask for it. In this case, the duty _Du is 2 ^* _vu ^* / _Vdc . The duty D _v is 2 × v _v ^* / V _dc . The duty D _w is 2 × v _w ^* / V _dc . Duty generator 101, the duty D _u, D _v, and outputs the D _w.

(Inverter 104)
In the present embodiment, the inverter 104 is a PWM inverter. As shown in FIG. 6, the inverter 104 includes a switching circuit 123a, 123b, 123c, 123d, 123e, 123f, and a conversion circuit, a base driver 120, a pair of freewheeling diodes 124a, 124b, 124c, 124d, 124e, 124f. A smoothing capacitor 121 and a DC power supply 122 are included. The DC power supply 122 represents an output rectified by a diode bridge or the like. In the present specification, a configuration in which the conversion circuit and the smoothing capacitor 121 are combined is referred to as an inverter.

The inverter 104 applies a voltage vector to the three-phase motor 102 by PWM control. Specifically, the power supply to the three-phase motor 102 is performed from the DC power source 122 via the switching elements 123a to 123f. More specifically, first, the duties _Du , _Dv , and _Dw are input to the base driver 120. Then, the duty D _u, D _v, D _w is converted into a drive signal for electrically driving the switching elements 123 a to 123 f. Next, each of the switching elements 123a to 123f operates according to the drive signal.

  In the present embodiment, the inverter 104 is a three-phase switching circuit using switching elements 123a to 123f. Examples of the switching elements 123a to 123f include a MOSFET (Metal Oxide Semiconductor Field Effect Transistor) and an IGBT (Insulated Gate Bipolar Transistor).

(Three-phase motor 102)
A three-phase motor 102 illustrated in FIG. 1 is a control target of the motor control device 100. A voltage vector is applied to the three-phase motor 102 by the inverter 104. “A voltage vector is applied to the three-phase motor 102” means that a voltage is applied to each of the three phases (U phase, V phase, W phase) on the three-phase AC coordinate in the three-phase motor 102. . In the present embodiment, each of the three phases (U phase, V phase, W phase) is selected from two types: a high voltage phase having a relatively high voltage and a low voltage phase having a relatively low voltage. The three-phase motor 102 is controlled so as to be one of the following.

The three-phase motor 102 in this embodiment is a synchronous motor. Specifically, the three-phase motor 102 in the present embodiment is a permanent magnet synchronous motor. The three-phase motor 102 may be an SPMSM (Surface Permanent Magnet Synchronous Motor) or an IPMSM (Interior Permanent Magnet Synchronous Motor). In SPMSM, the d-axis inductance L _d and the q-axis inductance L _q are the same. The IPMSM has a saliency in which the d-axis inductance L _d and the q-axis inductance L _q are different (generally, a reverse saliency such that L _q > L _d ). IPMSM can use reluctance torque in addition to magnet torque. For this reason, the driving efficiency of the IPMSM is extremely high.

(Effect of this embodiment)
Typically, the conversion circuit (see FIG. 6) in which the switching elements 123a to 123f and the freewheeling diodes 124a to 124f in the inverter 104 are paired includes a semiconductor element. In these semiconductor elements, a voltage drop occurs. The voltage drop makes the amplitude of the magnetic flux vector actually applied to the three-phase motor 102 smaller than the amplitude of the command magnetic flux vector. In general, the inverter 104 is provided with a dead time. The dead time can also cause the amplitude of the magnetic flux vector actually applied to the three-phase motor 102 to be smaller than the amplitude of the command magnetic flux vector. These errors become apparent when the induced voltage in the inverter 104 is small, such as when the three-phase motor 102 is started or driven at a low speed. For this reason, the amplitude of the voltage vector applied to the three-phase motor 102 is insufficient at the time of start-up, low-speed driving, etc., and the torque tends to be insufficient. However, in the present embodiment, the amplitude determination unit 115, as the armature current I _a to follow the command armature current I _a ^*, generates an amplitude correction amount [Delta] [Psi]. The command armature current I _a ^* is such that when the three-phase motor 102 is started and driven at a low speed, a motor current having a sufficiently large amplitude flows in the three-phase motor 102 and a motor magnetic flux having a sufficiently large amplitude is generated. Is set. That is, by generating the amplitude correction amount ΔΨ, it is possible to compensate for the decrease in the amplitude of the motor magnetic flux resulting from the above error. For this reason, torque shortage is eliminated and the three-phase motor 102 can be started stably. Further, the three-phase motor 102 can be stably driven at a low speed. Further, by using the large command armature current I _a ^* to make the amplitude correction amount ΔΨ larger than the amount necessary for this compensation, it is possible to further stabilize the starting of the three-phase motor 102 and the low-speed driving.

(Modification 1-1A)
Hereinafter, the motor control device of Modification 1-1A will be described. In the modified example 1-1A, the same parts as those in the first embodiment are denoted by the same reference numerals, and the description thereof may be omitted.

  As shown in FIG. 7, the motor control unit 203 of Modification 1-1A has a phase specifying unit 211 a instead of the phase specifying unit 111. Further, the motor control unit 203 has a torque estimation unit 221.

In the motor control unit 203, the torque estimation unit 221 estimates the torque from the estimated magnetic fluxes ψ _α , ψ _β and the shaft currents i _α , i _β (the estimated torque _Te is obtained). By the phase identifying unit 211a, a command velocity omega _ref ^* and the estimated torque T _e, the command flux vector [psi _s ^* phase theta _s ^* is identified.

(Torque estimation unit 221)
As shown in FIG. 8, the torque estimation unit 221, using Equation (13) determines the estimated torque T _e. P _n in equation (13) is the _number of pole pairs of the three-phase motor 102.

(Phase specific part 211a)
Phase identifying unit 211a from the command velocity omega _ref ^* and the estimated torque T _e, identifies the command flux vector [psi _s ^* phase theta _s ^*. As illustrated in FIG. 9A, the phase specifying unit 211a includes a high-pass filter 261a, a gain multiplication unit 262, a speed deviation calculation unit 223a, and a speed deviation integrator 216a. The phase specifying unit 211a is configured by a discrete system.

(High-pass filter 261a)
High-pass filter 261a is the vibration component of the estimated torque T _e identify only (torque vibration component) T _H (extraction).

(Gain multiplier 262)
Gain multiplication section 262 identifies the speed vibration component K ₁ T _H is multiplied by a gain K ₁ to the torque vibration component T _H.

The operations of the high pass filter 261a and the gain multiplication unit 262 are expressed by Expression (14). g is a cut-off frequency, and its unit is [rad / s]. s is a Laplace operator. K ₁ is a stabilization control gain.

(Speed deviation calculation unit 223a)
Speed difference calculating unit 223a calculates the speed deviation ω _ref ^* -K ₁ T _H command speed omega _ref ^* and speed vibration component K ₁ T _H. ω _ref ^* -K ₁ T _H can be considered to be corrected command speed.

(Speed deviation integrator 216a)
Speed deviation integrator 216a integrates the speed deviation ω _ref ^* -K ₁ T _H. This gives a command flux vector [psi _s ^* phase theta _s ^*. The speed deviation integrator 216a of the modified example 1-1A is configured by a discrete system. Therefore, the speed deviation integrator 216a identifies the amount of movement of each control cycle to the phase θ of the motor flux [psi _s moves with the speed deviation (corrected command ^{_{speed) ω ref * -K 1 T H}} , It can be said that the phase θ _s ^* of the command magnetic flux vector Ψ _s ^* is specified by using the specified movement amount (specifically, integration).

  The operations of the speed deviation calculator 223a and the speed deviation integrator 216a are expressed by Expression (15).

In Modification Example 1-1A, the torque estimation portion 221 calculates the estimated motor flux (estimated magnetic flux [psi _s), axis current i _alpha, and i _beta, (estimated torque T _e for estimating the motor torque using a ). Phase identification unit 211a includes high-pass filter 261a, the estimated torque T _e, the vibration component of the motor torque estimate (torque vibration component) T _H (specific) to. Phase identifying unit 211a, using the estimated torque vibration component T _H corrects the command speed omega _ref ^*, and identifies a moving amount using the corrected command speed ω _ref ^* -K ₁ T _H, it is identified movement amount using (specifically, integrated with) identifies the command flux vector [psi _s ^* phase theta _s ^*. According to the modified example 1-1A, the speed of the three-phase motor 102 can be prevented from deviating from the command speed ω _ref ^* . Therefore, when the motor control unit 203 is used, the three-phase motor 102 can be driven more stably than when the motor control unit 103 is used.

(Modification 1-1B)
It can replace with the phase specific part 211a of modification 1-1A, and can also use the phase specific part 211b shown to FIG. 9B. Hereinafter, the phase specifying unit 211b will be described.

(Phase identifying unit 211b)
Phase identification unit 211b from the command velocity omega _ref ^* and the estimated torque T _e, identifies the command flux vector [psi _s ^* phase theta _s ^*. As illustrated in FIG. 9B, the phase specifying unit 211b includes a low-pass filter 261b, a gain multiplier 262, a speed integrator 216b, and a phase deviation calculator 223b. The phase specifying unit 211b is configured by a discrete system.

(Low-pass filter 261b)
Low pass filter 261b is stationary component of the estimated torque T _e (torque constant component) T _L only certain (extraction).

(Gain multiplier 262)
The gain multiplication unit 262 multiplies the steady torque component T _L by the gain K ₁ to specify the product K ₁ T _L.

  The operations of the low-pass filter 261b and the gain multiplication unit 262 are expressed by Expression (16).

(Velocity integrator 216b)
The speed integrator 216b integrates the command speed ω _ref ^* . Since the integration of the command speed ω _ref ^* has a phase dimension, the integration of the command speed ω _ref ^* may be referred to as a phase X below. The phase X is the same as the phase θ _s ^* obtained by the integrator 116 (phase specifying unit 111) of the first embodiment.

(Phase deviation calculation unit 223b)
The phase deviation calculation unit 223b subtracts the product K ₁ T _L from the phase X. This gives a command flux vector [psi _s ^* phase theta _s ^*.

  The operations of the speed integrator 216b and the phase deviation calculator 223b are expressed by Expression (17).

The phase specifying unit 211b of Modification 1-1B is configured as a discrete system. Therefore, it can be said that the phase specifying unit 211b specifies the movement amount using the command speed ω _ref ^* and specifies the phase X of the command magnetic flux vector using the specified movement amount. Further, the phase specifying unit 211b corrects the specified phase X using the estimated steady component (torque steady component) _TL of the motor torque. This prevents the speed of the three-phase motor 102 from deviating from the command speed ω _ref ^* .

(Modification 1-2A)
Hereinafter, the motor control device of Modification 1-2A will be described. Note that in the modified example 1-2A, the same portions as those in the first embodiment are denoted by the same reference numerals, and description thereof may be omitted.

  As illustrated in FIG. 10A, the motor control unit 303 a of Modification 1-2 </ b> A includes an amplitude specifying unit 315 a instead of the amplitude specifying unit 115.

(Amplitude specifying unit 315a)
The amplitude specifying unit 315a generates a corrected amplitude | Ψ _s ^** | as an amplitude to be given to the command magnetic flux specifying unit 112 from the axial currents i _α and i _β and the estimated magnetic flux ψ _s (estimated magnetic flux ψ _α , ψ _β ). Identify. The amplitude specifying unit 315a includes a temporary setting unit 130, an amplitude correction amount generating unit 314a, and a command magnetic flux adding unit 117.

(Amplitude correction amount generation unit 314a)
The amplitude correction amount generation unit 314a specifies the amplitude correction amount Δψ from the axial currents i _α and i _β and the estimated magnetic flux ψ _s (estimated magnetic flux ψ _α , ψ _β ). As illustrated in FIG. 11A, the amplitude correction amount generation unit 314a includes an error parameter calculation unit 321a, an error parameter deviation calculation unit 322, and a PI compensation unit 323.

The amplitude correction amount generation unit 314a performs the same operation regardless of whether the d-axis inductance L _d and the q-axis inductance L _q are different from each other. Specifically, when there is an inductance difference, a value between the d-axis inductance and the q-axis inductance can be used as the inductance L. Further, if the magnetic saliency is not large, there is no harm in handling the L = L _d. That is, as the inductance value, a d-axis inductance value, a value larger than the d-axis inductance and smaller than the q-axis inductance, or a value smaller than the d-axis inductance and larger than the q-axis inductance can be used.

Patent Document 1 is helpful in setting the inductance L as described above. Patent Document 1 describes a technique related to a dm-qm coordinate system. The dm-qm coordinate system makes it possible to treat a motor having magnetic saliency such as a permanent magnet synchronous motor having an embedded magnet structure in the same manner as a permanent magnet synchronous motor having no magnetic saliency. MTPA control (maximum torque control) can be performed by using the dm-qm coordinate system and setting the dm-axis current (γ-axis current in the control coordinate system) to zero. In Modification 1-2A, MTPA control can be used for steady operation rather than for starting and low speed driving. If 3-phase motor 102 has a magnetic saliency, the d-axis current to the dm-axis current, in a magnet flux [psi _a extended flux linkage vector [Phi _exm, the inductance L to the virtual inductance L _m, can be replaced, respectively . For details of the dm-axis current, the extended flux linkage vector Φ _exm and the virtual inductance L _m , refer to Patent Document 1 (Formula 36 and paragraphs 0182 to 0183). Note that L _m satisfies L _d ≦ L _m <L _q . When there is no inductance difference, the dm-qm coordinate system and the general dq coordinate system coincide with each other, and L _m = L _d = L _q may be set. That is, the idea about the case where there is an inductance difference includes the idea about the case where there is no inductance difference.

(Error parameter calculator 321a)
Error parameter calculation unit 321a includes virtual inductance (inductance of the three-phase motor 102) L _m and the axial current i _alpha, i _beta and estimated flux [psi _s (estimated magnetic flux Ψ _α, Ψ _β) from a, calculates an error parameter ε . Specifically, first, estimate the armature reaction magnetic flux (obtain the estimated armature reaction flux L _m i _a). The alpha-axis component and beta-axis component of the estimated armature reaction flux L _m i _a, respectively estimated armature reaction flux L _m i _α, referred to as estimated armature reaction flux L _m i _β. The estimated armature reaction magnetic flux L _m i _α and the estimated armature reaction magnetic flux L _m i _β are the products of the virtual inductance L _m and the axial currents i _α and i _β . Next, the magnet magnetic flux is estimated from the estimated magnetic flux Ψ _s (estimated magnetic flux Ψ _α , Ψ _β ) and the estimated armature reaction magnetic flux L _m i _a (estimated armature reaction magnetic flux L _m i _α , L _m i _β ) ( Estimate magnetic flux Ψ ' _ae ). The α-axis component and β-axis component of the estimated magnet magnetic flux Ψ ′ _ae are described as estimated magnet magnetic flux Ψ ′ _aeα and Ψ ′ _aeβ , respectively. Specifically, as shown in equations (18) and (19), the estimated magnetic flux Ψ ′ _{aeα is} obtained by subtracting the estimated armature reaction magnetic fluxes L _m i _α and L _m i _β from the estimated magnetic fluxes Ψ _α and Ψ _β. , Ψ ′ _aeβ . Next, an error parameter ε is calculated from the estimated magnet magnetic fluxes Ψ ′ _aeα and Ψ ′ _aeβ and the axial currents i _α and i _β as shown in Expression (20).

(Error parameter deviation calculation unit 322)
The error parameter deviation calculation unit 322 calculates a deviation between the command error parameter ε ^* and the error parameter ε (error parameter deviation Δε: ε ^* −ε). As the error parameter deviation calculation unit 322, a known operator can be used.

A PI compensation unit 323 described later performs control such that the error parameter deviation Δε becomes zero. When the entire control system is constructed so that the MTPA control can be realized, the estimated magnet magnetic flux ψ ′ _ae and the axial currents i _α , i _β are orthogonal to each other, that is, the inner product ψ ′ shown in the equation (20). _The command error parameter ε ^* should be set to zero so that _aeα i _α + Ψ ′ _aeβ i _β is zero. The fact that the inner product ψ ′ _aeα i _α + ψ ′ _aeβ i _β becomes zero means that the d-axis current becomes zero, and that the d-axis current becomes zero is a condition for establishing the MTPA control. However, the MTPA control is not necessarily suitable as control for preventing torque shortage when the three-phase motor 102 is started or driven at a low speed. Therefore, the error parameter deviation calculation unit 322 uses a command error parameter ε ^* for preventing torque shortage, not for MTPA control. Specifically, a positive command error parameter ε ^* (greater than zero) is used. As a result, a positive d-axis current flows through the three-phase motor 102 and a large amplitude correction amount ΔΨ is obtained as compared with the case where MTPA control is performed, and the three-phase motor 102 is stably started or driven at a low speed. It is possible to ensure sufficient motor torque. The command error parameter ε ^* can be any positive constant. The command error parameter ε ^* can be set based on an empirical rule, set based on a motor parameter, or set through prior measurement according to the application of the three-phase motor 102 or the like. Typically, the command error parameter ε ^* is made smaller during steady operation than during start-up and low-speed driving. Specifically, the command error parameter ε ^{* is set} to zero. Thereby, high-efficiency steady operation of the three-phase motor 102 becomes possible.

In the error parameter deviation calculation unit 322 of the modification 1-2A, the command error parameter ε ^* is generated according to the equation (21). In the equation (21), Ψ _a is a magnetic flux parameter (a constant given as the amplitude of the magnetic flux generated by the permanent magnet in the three-phase motor 102). i _d ^* is a command d-axis current. The command d-axis current i _d ^* can be an arbitrary positive constant. The command d-axis current i _d ^* can be set based on an empirical rule, set based on a motor parameter, or set through prior measurement according to the use of the three-phase motor 102 or the like. Typically, during steady operation, the command d-axis current i _d ^* is made smaller than at start-up and low-speed drive. Specifically, the command d-axis current i _d ^{* is set} to zero. Thereby, high-efficiency steady operation of the three-phase motor 102 becomes possible.

(PI compensation unit 323)
The PI compensation unit 323 acquires the error parameter deviation Δε and specifies the amplitude correction amount ΔΨ so that it is zero. As a result, the error parameter ε follows the command error parameter ε ^* . Specifically, as shown in Expression (22), the amplitude correction amount ΔΨ is obtained by performing a proportional / integral calculation with the error parameter deviation Δε as an input. K _{p in} equation (22) is a proportional gain. K _I is an integral gain.

As can be understood from the equation (22) and the command error parameter ε ^* being a positive value, in this embodiment, the error parameter ε (= inner product ψ ′ _aeα i _α specified by the error parameter calculation unit 321a is used. The amplitude correction amount ΔΨ is specified by the amplitude correction amount generation unit 314a so that + Ψ ′ _aeβ i _β ;

As described above, the amplitude specifying unit 315a includes (i) the temporary setting unit 130 that sets the temporary amplitude | Ψ _s ^* | and (ii) the three-phase specified using the signal fed back from the three-phase motor 102. An amplitude correction amount generation unit 314a that generates an amplitude correction amount ΔΨ using the control target amount applied to the motor 102, and (iii) an amplitude to be given to the command magnetic flux specifying unit 112 using the amplitude correction amount ΔΨ. And a correction unit (command magnetic flux addition unit 117) that specifies a correction amplitude | Ψ _s ^** | larger than the provisional amplitude | Ψ _s ^* |. According to this configuration, the motor magnetic flux Ψ _s is easily secured. That is, this configuration is suitable for preventing torque shortage. In the modified example 1-2A, a physical quantity correlated with the reactive power applied to the three-phase motor 102 is used as the control target quantity. Specifically, a second inner product (error parameter ε = inner product Ψ ′ _aeα i _α + Ψ ′ _aeβ i _β ) between the motor current flowing through the three-phase motor 102 and the magnetic flux of the permanent magnet of the three-phase motor 102 is specified. The second inner product is used as the physical quantity described above. The command error parameter ε ^* , which is a positive value, is used as the target value. Then, the amplitude correction amount ΔΨ is specified by feedback control that makes the deviation Δε (= ε ^* −ε) between the command error parameter ε ^* and the error parameter ε zero. Therefore, it can be said that the amplitude correction amount generation unit 314a generates the amplitude correction amount by feedback control that converges the deviation between the control target amount and the target value to zero. In the modified example 1-2A, through such feedback control, the amplitude correction amount generation unit 314a is large if the deviation obtained by subtracting the control target amount (error parameter ε) from the target value (command error parameter ε ^* ) is large. The larger the amplitude correction amount Δψ is specified, and the correction unit (command magnetic flux adding unit 117) specifies the larger correction amplitude | ψ _s ^** | as the amplitude correction amount Δψ is larger.

In the modified example 1-2A, the amplitude specifying unit 315a generates the amplitude correction amount ΔΨ so that the error parameter ε follows the command error parameter ε ^* . The command error parameter ε ^* is set so that a motor current having a sufficiently large amplitude and a motor magnetic flux having a sufficiently large amplitude are applied to the three-phase motor 102 when the three-phase motor 102 is started and driven at a low speed. Is set. That is, according to the modified example 1-2A, as in the first embodiment, the torque shortage is eliminated, and the three-phase motor 102 can be started stably. Further, the three-phase motor 102 can be stably driven at a low speed.

12A to 12C show simulation results using various motor parameters. In this simulation, starting of the three-phase motor 102 was started at t = 0.2 seconds. In this simulation, the command d-axis current i _d ^* is set to 5.5 A from t = 0.2 seconds to t = 1.7 seconds, changed to 0 A at t = 1.7 seconds, and t = 1 After 7 seconds, it was kept at 0A. The graphs of FIGS. 12A to 12C are for no load. FIG. 12A represents the time change of the d-axis current i _d and the q-axis current i _q . FIG. 12B represents the time variation of the absolute value of the correction amplitude | ψ _s ^** | and the estimated magnetic flux ψ _s . FIG. 12C shows the change over time in the command speed ω _ref ^* and the speed of the three-phase motor 102. From the simulation results, the d-axis current i _d is also 5.5 A during the period of t = 0.2 to 1.7 seconds where the command d-axis current i _d ^* is 5.5 A (FIG. 12A), and a large correction is made. It can be seen that absolute values of the amplitude | Ψ _s ^** | and the estimated magnetic flux Ψ _s are obtained (FIG. 12B), that is, the motor torque is secured. Also, it can be seen that the d-axis current i _d is also 0 A during the period after t = 1.7 seconds when the command d-axis current i _d ^* is 0 A (FIG. 12A), that is, MTPA is realized. .

(Modification 1-2B)
Hereinafter, the motor control device of Modification 1-2B will be described. Note that in the modified example 1-2B, the same parts as those in the modified example 1-2A are denoted by the same reference numerals, and description thereof may be omitted.

  As illustrated in FIG. 10B, the motor control unit 303b of Modification 1-2B includes an amplitude specifying unit 315b instead of the amplitude specifying unit 315a. The amplitude specifying unit 315b includes an amplitude correction amount generation unit 314b instead of the amplitude correction amount generation unit 314a.

(Amplitude correction amount generation unit 314b)
As illustrated in FIG. 11B, the amplitude correction amount generation unit 314b includes an error parameter calculation unit 321b, an error parameter deviation calculation unit 322, and a PI compensation unit 323.

(Error parameter calculation unit 321b)
The error parameter calculator 321b calculates an error parameter ε from the virtual inductance L _m (inductance of the three-phase motor 102), the axial currents i _α , i _β and the estimated magnetic flux ψ _s (estimated magnetic flux ψ _α , ψ _β ). . Specifically, the inner product Ψ _α i _α + Ψ _β i _β of the estimated magnetic flux Ψ _s (estimated magnetic flux Ψ _α , Ψ _β ) and the axial currents i _α , i _β is specified. A product L _m (i _α ² + i _β ² ) of the virtual inductance and the square of the amplitude of the current is specified from the virtual inductance L _m and the axial currents i _α and i _β . The product L _m (i _α ² + i _β ² ) is subtracted from the inner product Ψ _α i _α + Ψ _β i _β to determine the difference Ψ _α i _α + Ψ _β i _β −L _m (i _α ² + i _β ² ), and the error parameter Get ε. The calculation performed by the error parameter calculation unit 321b is expressed by Expression (23).

In the modified example 1-2B, the amplitude correction amount generation unit 315b identifies the first inner product Ψ _α i _α + Ψ _β i _β of the motor current flowing through the three-phase motor 102 and the motor magnetic flux, and the identified first inner product The physical quantity (error parameter ε) described in the modified example 1-2A is specified using Ψ _α i _α + Ψ _β i _β . The amplitude correction amount generation unit 314b of Modification 1-2B uses an expression different from the expression used in the amplitude correction amount generation section 314a of Modification 1-2A, but the same amplitude correction amount as that of Modification 1-2A Specify ΔΨ. Therefore, if the motor control unit 303b of the modified example 1-2B is used, the same effect as when the motor control unit 303a is used can be obtained.

Note that the inner product (first inner product) Ψ _α i _α + Ψ _β i _β itself can be used as the control target amount instead of the error parameter ε. Also in this case, those skilled in the art can appropriately set the target value. That is, “specifying the first inner product Ψ _α i _α + Ψ _β i _β and specifying the physical quantity using the specified first inner product” is a concept including using the first inner product itself as the physical quantity.

The reactive power applied to the three-phase motor 102 can also be used as the control target amount. The reactive power can be obtained by multiplying the inner product Ψ _α i _α + Ψ _β i _β by the command speed ω _ref ^* . The reactive power can be obtained by differentiating the phase of the estimated magnetic flux ψ _s to estimate the speed of the three-phase motor 102 (determining the estimated speed ω _r ) and multiplying that speed by the inner product Ψ _α i _α + Ψ _β i _β. it can. A phase estimation unit 518 described later can be used to specify the phase of the estimated magnetic flux Ψ _s , and a speed estimation unit 920 described later can be used to differentiate the phase. The reactive power can also be obtained from the shaft currents i _α and i _β and the shaft voltages v _α ^* and v _β ^* . That is, the amplitude correction amount generation unit specifies (a) the first inner product Ψ _α i _α + Ψ _β i _β between the motor current flowing through the three-phase motor 102 and the motor magnetic flux, and the identified first inner product Ψ _α i _The reactive power may be specified by multiplying _α + Ψ _β i _β by the estimated speed ω _r or the command speed ω _ref ^* , or (b) the motor current flowing through the three-phase motor 102 is expressed by two-phase coordinates. The shaft currents i _α and i _β that are expressed and the voltage vectors to be applied to the three-phase motor 102 are invalid using the shaft voltages v _α ^* and v _β ^* that are expressed by two-phase coordinates. The power may be specified. In an example in which reactive power is used as the control target amount, the amplitude correction amount ΔΨ is specified by the amplitude correction amount generation unit so that the reactive power Q becomes positive. Specifically, the reactive power Q is specified so that the error parameter ε is positive, similarly to the modified examples 1-2A and 1-2B. Here, as understood from the equation (23), the error parameter ε is positive is _{Q = ω (Ψ α i α} + Ψ β i β)> ωL m (i α 2 + i β 2) is satisfied Is equal. That is, the reactive power Q is specified so that this inequality is established. Note that ω is the speed of the three-phase motor 102, and the estimated speed ω _r or the command speed ω _ref ^* can be used as ω.

(Modification 1-3)
Hereinafter, the motor control device of Modification 1-3 will be described. In Modification 1-3, parts similar to Modification 1-1A or Modification 1-2A may be denoted by the same reference numerals and description thereof may be omitted.

  As shown in FIG. 13, the motor control unit 403 includes the torque estimation unit 221 and the phase identification unit 211a described in Modification 1-1A (FIGS. 7, 8, and 9A), and Modification 1-2A (FIG. 10A). And the amplitude specifying unit 315a described in FIG. 11A). According to Modification 1-3, both the effects of Modification 1-1A and Modification 1-2A can be obtained.

  Note that an amplitude correction amount generation unit 314b may be provided instead of the amplitude correction amount generation unit 314a.

(Second Embodiment)
Hereinafter, the motor control device of the second embodiment will be described. Note that in the second embodiment, the same parts as those in the first embodiment are denoted by the same reference numerals, and description thereof may be omitted.

  As illustrated in FIG. 14, the motor control unit 503 of the second embodiment includes a phase specifying unit 511 instead of the phase specifying unit 111. Further, the motor control unit 503 has a phase estimation unit 518.

(Phase estimation unit 518)
The phase estimation unit 518 obtains the phase θ _s of the estimated magnetic flux ψ _s from the estimated magnetic flux ψ _s (estimated magnetic flux ψ _α , ψ _β ). Specifically, the phase estimation unit 518 obtains the phase θ _s of the estimated magnetic flux Ψ _s by the equation (24).

(Phase identifying unit 511)
The phase specifying unit 511 obtains the phase θ _s ^* of the command magnetic flux vector ψ _s ^* from the command speed ω _ref ^* and the phase θ _s of the estimated magnetic flux ψ _s . As illustrated in FIG. 15, the phase identification unit 511 includes a multiplication unit 520 and a phase addition calculation unit 542.

(Multiplier 520)
Multiplier 520 identifies movement amount Δθ by multiplying command speed ω _ref ^* by control cycle T _s .

(Phase addition operation unit 542)
The phase addition operation unit 542 adds the movement amount Δθ and the phase θ _s of the estimated magnetic flux ψ _s to obtain the phase θ _s ^* of the command magnetic flux vector ψ _s ^* .

The motor control unit 503 according to the second embodiment represents the shaft currents i _α , i that represent the phase currents (motor currents) i _u , i _w on the three-phase AC coordinates in the three-phase motor 102 by the two-phase coordinates. _A three-phase motor 102 using _β and shaft voltages v _α ^* and v _β ^* representing the voltage vectors v _u , v _v and v _w to be applied to the three-phase motor 102 by two-phase coordinates. Is provided with a motor magnetic flux estimator 108 for estimating a motor magnetic flux applied to the motor (determining an estimated magnetic flux Ψ _s ). The motor control unit 503 includes a phase estimation unit 518 that estimates the phase θ _{s of the} motor magnetic flux using the estimated motor magnetic flux. The phase specifying unit 511 uses the phase θ _s of the motor magnetic flux Ψ _s estimated by the phase estimation unit 518 and the movement amount Δθ (more specifically, the phase θ _s and the movement amount Δθ are added together). ) Specify the phase θ _s ^* of the command magnetic flux vector Ψ _s ^* . According to the motor control unit 503 of the second embodiment, the phase θ _s ^* of the command magnetic flux vector Ψ _s ^* can be easily specified. Further, the motor magnetic flux estimated to specify the phase θ _s ^* of the command magnetic flux vector Ψ _s ^* is used, and axial currents i _α and i _β are used for the estimation. This means that the motor current actually flowing in the three-phase motor 102 is reflected in the specification of the phase θ _s ^* of the command magnetic flux vector Ψ _s ^* . That is, this contributes to appropriately setting the phase θ _s ^* of the command magnetic flux vector Ψ _s ^* , and helps to stabilize the driving of the three-phase motor 102.

(Modification 2-1A)
Hereinafter, the motor control device of Modification 2-1A will be described. Note that in the modification 2-1A, the same reference numerals are given to the same parts as those in the modification 1-1 or the second embodiment, and the description may be omitted.

  As illustrated in FIG. 16, the motor control unit 603 includes the torque estimation unit 221 described in the modified example 1-1A (FIGS. 7, 8, and 9 </ b> A) and the second embodiment (FIGS. 14 and 15). The phase estimation unit 518 described is included. In addition, the motor control unit 603 includes a phase specifying unit 611a instead of the phase specifying unit 211a or 511.

(Phase identifying unit 611a)
The phase specifying unit 611a specifies the phase θ _s ^* of the command magnetic flux vector ψ _s ^* from the command speed ω _ref ^* , the estimated torque _Te, and the phase θ _s of the estimated magnetic flux ψ _s . As illustrated in FIG. 17A, the phase specifying unit 611a includes a high-pass filter 261a, a gain multiplier 262, a speed deviation calculator 223a, a multiplier 620a, and a phase addition calculator 642a.

(Multiplier 620a)
Multiplying unit 620a obtains a movement amount Δθ by multiplying the control period T _S of the speed deviation ω _ref ^* -K ₁ T _H.

(Phase addition operation unit 642a)
The phase addition operation unit 642a obtains the phase θ _s ^* of the command magnetic flux vector ψ _s ^* by adding the movement amount Δθ to the phase θ _s of the estimated magnetic flux ψ _s .

Phase identification unit 611a variations 2-1A corrects the command speed omega _ref ^* using the estimated torque fluctuation component T _H, the moving amount using the corrected command speed ω _ref ^* -K ₁ T _H By specifying Δθ and using the specified movement amount Δθ (specifically, adding the phase θ _s of the motor magnetic flux ψ _s estimated by the phase estimation unit 518 and the movement amount Δθ), the command magnetic flux vector Ψ _s ^* of identifying the phase θ _s ^*. According to Modification 2-1A, both the effects of Modification 1-1A and the effects of the second embodiment can be obtained.

(Modification 2-1B)
It can replace with the phase specific part 611a of modification 2-1A, and can also use the phase specific part 611b shown to FIG. 17B. Hereinafter, the phase specifying unit 611b will be described. In the modified example 2-1B, the same parts as those in the modified example 2-1A may be denoted by the same reference numerals and description thereof may be omitted.

(Phase identifying unit 611b)
Phase identification unit 611b from the command velocity omega _ref ^* and the estimated torque T _e and the phase theta _s estimated flux [psi _s, identifies the command flux vector [psi _s ^* phase theta _s ^*. As illustrated in FIG. 17B, the phase specifying unit 611b includes a high-pass filter 261a, a multiplying unit 663, a multiplying unit 620b, a movement amount deviation calculating unit 623b, and a phase addition calculating unit 642b.
(Multiplier 663)
Multiplication section 663 specifies the product K ₂ T _H is multiplied by a gain K ₂ to the torque vibration component T _H. The gain K ₂ is the product of the gain K ₁ and the control period T _S of the modified example 1-1A and modified example 2-1A.

(Multiplier 620b)
Multiplying unit 620b multiplies the control period T _s in the command velocity omega _ref ^*, identifying the product omega _ref ^* T _s. The product ω _ref ^* T _s is the same as the movement amount Δθ obtained by the multiplication unit 520 of the second embodiment.

(Movement deviation calculation unit 623b)
Movement amount deviation calculation unit 623b, by subtracting the product K ₂ T _H from the product ω _ref ^* T _s, identifies the difference ^{_{ω ref * T s -K 2 T}} H.

(Phase addition operation unit 642b)
Phase adder 642b, by adding the difference ^{_{ω ref * T s -K 2 T}} H to the phase theta _s estimated flux [psi _s, obtains a command flux vector [psi _s ^* phase theta _s ^*.

In the modified example 2-1B, the phase specifying unit 611b specifies the movement amount (product ω _ref ^* T _s ) using the command speed ω _ref ^* , and the motor in which the specified movement amount ω _ref ^* T _s is estimated. Correction is performed using the vibration component (torque vibration component) T _{H of the} torque, and the correction is performed using the corrected movement amount (difference ω _ref ^* T _s −K ₂ T _H ) (more specifically, the phase θ _s and the correction) movement amount ^{_{ω ref * T s -K 2 T}} H and added together) identifies the command flux vector [psi _s ^* phase theta _s ^*. Since the block diagrams of FIGS. 17A and 17B and K ₂ = K ₁ × T _S , the phase specifying unit 611b of the modified example 2-1B and the phase specifying unit 611a of the modified example 2-1A have the same phase θ _s. It is clear to specify ^* . Therefore, according to the modified example 2-1B, the same effect as the modified example 2-1A can be obtained.

(Modification 2-2)
Hereinafter, the motor control device of Modification 2-2 will be described. In addition, in the modification 2-2, the same code | symbol is attached | subjected about the part similar to the modification 1-2A or 2nd Embodiment, and description may be abbreviate | omitted.

  As shown in FIG. 18, the motor control unit 703 includes the amplitude specifying unit 315a described in the modified example 1-2A (FIGS. 10A and 11A) and the phase described in the second embodiment (FIGS. 14 and 15). A specifying unit 511 and a phase estimation unit 518 are included. According to Modification 2-2, both the effects of Modification 1-2A and the effects of the second embodiment can be obtained.

  Note that an amplitude correction amount generation unit 314b may be provided instead of the amplitude correction amount generation unit 314a.

(Modification 2-3)
Hereinafter, the motor control device of Modification 2-3 will be described. Note that in the modification 2-3, the same parts as those in the modification 1-2A or the modification 2-1A are denoted by the same reference numerals, and description thereof may be omitted.

  As shown in FIG. 19, the motor control unit 803 includes the amplitude specifying unit 315a described in the modification 1-2A (FIGS. 10A and 11A) and the phase described in the modification 2-1A (FIGS. 16 and 17A). A specifying unit 611a and a phase estimation unit 518 are included. According to the modified example 2-3, both the effects of the modified example 1-2A and the modified example 2-1A can be obtained.

  Note that an amplitude correction amount generation unit 314b may be provided instead of the amplitude correction amount generation unit 314a.

(Third embodiment)
Hereinafter, the motor control device of the third embodiment will be described. Note that in the third embodiment, the same portions as those of the modified example 2-1A are denoted by the same reference numerals, and description thereof may be omitted.

  As shown in FIG. 20, the motor control unit 903 has an amplitude specifying unit 915 instead of the amplitude specifying unit 115. The motor control unit 903 includes a phase specifying unit 911 instead of the phase specifying unit 611a. The motor control unit 903 includes a speed estimation unit 920, a command torque generation unit 921, and a torque deviation calculation unit 922.

(Speed estimation unit 920)
The speed estimation unit 920 uses the phase θ _s (n) obtained in the current control cycle and the phase θ _s (n−1) obtained in the previous control cycle to calculate the estimated speed ω using Equation (25). _{Find r} . The speed estimation unit 920 is a known speed estimator. Here, T _s means a control period (sampling period). n is a time step.

(Command torque generator 921)
Command torque generator 921, the command velocity omega _ref ^* and the estimated speed omega _r, determining the command torque T _e ^*. Specifically, the command torque generation unit 921 obtains the command torque _Te ^{* according} to the equation (26). K _sP in the equation (26) is a proportional gain. K _sI is an integral gain. The command torque generator 921 is a known PI compensator.

(Amplitude specifying unit 915)
The amplitude specifying unit 915 specifies the correction amplitude | Ψ _s ^** | as the amplitude to be given to the command magnetic flux specifying unit 112 from the shaft currents i _α and i _β and the command torque _Te ^* . The amplitude specifying unit 915 includes a temporary setting unit 930, an amplitude correction amount generation unit 114, and a command magnetic flux addition unit (correction unit) 117.

(Temporary setting unit 930)
The temporary setting unit 930 sets the temporary amplitude | Ψ _s ^* | using the command torque T _e ^* . The temporary setting unit 930 can be configured by using an operator that stores a lookup table, a calculation formula (approximation formula), and the like. When using a look-up table, a look-up table representing the correspondence between the command torque T _e ^* and the provisional amplitude | Ψ _s ^* | can be prepared in advance. Calculation formulas for operators can also be prepared in advance. Such a lookup table and calculation formula can be set based on measurement data or theory performed in advance. In this embodiment, the relationship between the torque and the magnetic flux satisfying the maximum torque / current control (MTPA) that can generate the maximum torque with the minimum current is used.

Specifically, the provisional amplitude | Ψ _s ^* | can be specified based on the following concept. That is, when a motor having no magnetic saliency is used as the three-phase motor 102, the amplitude | Ψ _s | of the motor magnetic flux and the motor torque T are approximated by the equations (27A) and (27B). | Ψ _a | is a magnetic flux parameter. L is the inductance per phase of the armature winding of the three-phase motor. i _q is a q-axis current. P _n is the number of pole pairs of the motor. Expression (27C) is derived from Expressions (27A) and (27B). A relational expression between the command torque T _e ^* and the temporary amplitude | Ψ _s ^* | is derived by replacing T with the command torque T _e ^* in FIG. 20 and | Ψ _s | with the temporary amplitude | Ψ _s ^* |. . If this relational expression is used, the provisional amplitude | Ψ _s ^* | can be obtained from the command torque T _e ^* . Of course, a conversion table can also be created. When a motor having magnetic saliency is used as the three-phase motor, the motor magnetic flux amplitude | ψ _s | and the motor torque T are approximated by equations (27D) and (27E). L _d is the d-axis inductance. L _q is a q-axis inductance. i _d is a d-axis current. The d-axis current i _d and the q-axis current i _q generally satisfy the relationship of Expression (27F). Expressions (27D), (27E), and (27F) provide a conversion table that can specify the motor magnetic flux amplitude | Ψ _s | from the motor torque T without using the variables i _d and i _q . By replacing T with the command torque T _e ^* in FIG. 20 and | Ψ _s | with the amplitude | Ψ _s ^* |, the temporary amplitude | Ψ _s ^* | can be specified from the command torque T _e ^* .

(Torque deviation calculator 922)
Torque deviation calculation unit 922, the command torque T _e ^* and the estimated torque T _e and the deviation (torque deviation ΔT: T _e ^* -T _e) Request. A known operator can be used as the torque deviation calculation unit 922.

(Phase identifying unit 911)
The phase specifying unit 911 specifies the phase θ _s ^* of the command magnetic flux vector ψ _s ^* from the torque deviation ΔT and the phase θ _s of the estimated magnetic flux ψ _s . As illustrated in FIG. 21, the phase identification unit 911 includes a phase change amount generation unit 919 and a phase addition calculation unit 942.

(Phase change amount generation unit 919)
The phase change amount generation unit 919 obtains a movement amount Δθ for each control cycle in which the phase of the motor magnetic flux should move from the torque deviation ΔT. Specifically, the phase change amount generation unit 919 obtains the movement amount Δθ using Expression (28). In the equation (28), _KθP is a proportional gain. K _θI is an integral gain. The phase change amount generation unit 919 brings the torque deviation ΔT close to zero. In this respect, it can be said that the phase change amount generation unit 919 constitutes a torque compensation mechanism. When the phase change amount generation unit 919 is incorporated in a digital control device such as a DSP or a microcomputer, the integrator required for the calculation in Expression (28) can be configured as a discrete system.

(Phase addition operation unit 942)
The phase addition operation unit 942 identifies the phase θ _s ^* of the command magnetic flux vector Ψ _s ^* from the movement amount Δθ and the phase θ _s of the estimated magnetic flux Ψ _s . Specifically, the phase addition calculation unit 942 obtains the phase θ _s ^* by adding the movement amount Δθ and the phase θ _s according to the equation (29).

The motor control device of the third embodiment uses the inverter 104 to adjust the three-phase motor 102 so that the motor magnetic flux and the motor torque of the three-phase motor 102 follow the command magnetic flux vector Ψ _s ^* and the command torque _Te ^*. Apply a voltage vector. In the motor magnetic flux estimation unit 108, motor currents flowing through the three-phase motor 102 are applied to the three-phase motor 102 with shaft currents i _α and i _β that are expressed by α-β coordinates (two-phase coordinates). The estimated magnetic flux Ψ _s is specified from the shaft voltages v _α ^* and v _β ^* which are the power voltage vectors represented by α-β coordinates (two-phase coordinates) (the motor applied to the three-phase motor 102) Magnetic flux is estimated). The torque estimation portion 221, the axial current i _alpha, i _beta, from the estimated flux [psi _s, the estimated torque T _e is specified (the motor torque is estimated). The speed estimating section 920, the phase of the estimated torque T _e, the estimated velocity omega _r is specified (the speed of the 3-phase motor 102 is estimated). In the command torque generator 921, a command velocity omega _ref ^*, from the estimated velocity omega _r, the command torque T _e ^* is generated. Phase identification unit 911, the movement amount of the phase of the motor flux using torque deviation ΔT to identify the movement amount Δθ in each control cycle to be moved, has been identified between the command torque T _e ^* and the estimated torque T _e and [Delta] [theta], identifies the command flux vector [psi _s ^* phase theta _s ^* using the phase theta _s estimated flux [psi _s. According to the third embodiment, a positive d-axis current flows through the three-phase motor 102 and a large amplitude correction amount ΔΨ is obtained as compared with the case where MTPA control is performed, and the three-phase motor 102 is stabilized. It is possible to secure a motor torque sufficient for starting and driving at a low speed.

(Modification 3-1)
Hereinafter, the motor control device of Modification 3-1 will be described. Note that in Modification 3-1, the same parts as those in Modification 1-2A or the third embodiment are denoted by the same reference numerals, and description thereof may be omitted.

  As shown in FIG. 22, the motor control unit 1003 has an amplitude specifying unit 1015 instead of the amplitude specifying unit 915 of the motor control unit 903. The amplitude specifying unit 1015 has an amplitude correction amount generation unit 314a instead of the amplitude correction amount generation unit 114.

  According to the modified example 3-1, as in the modified example 1-2A and the third embodiment, it is possible to secure a motor torque sufficient to stably start or drive the three-phase motor 102 at a low speed. .

Further, at the time of steady operation, the command error parameter ε ^* (command d-axis current i _d ^* ) can be made smaller than at the time of start-up and low-speed drive. Specifically, the command error parameter ε ^* (command d-axis current i _d ^* ) can be made zero. In this way, the provisional magnetic flux | Ψ _s ^* | suitable for MTPA control is specified in the temporary setting unit 930, and the amplitude correction amount ΔΨ suitable for MTPA control is generated in the amplitude correction amount generation unit 314a. That is, the command magnetic flux adding unit 117 corrects the provisional magnetic flux | Ψ _s ^* | suitable for MTPA control by the amplitude correction amount ΔΨ suitable for MTPA control, thereby generating a corrected amplitude | Ψ _s ^** |. . Therefore, MTPA control with high responsiveness and high accuracy is possible.

  Note that an amplitude correction amount generation unit 314b may be provided instead of the amplitude correction amount generation unit 314a.

(Fourth embodiment)
The technique according to the present disclosure can also be applied when performing primary magnetic flux control as shown in Non-Patent Document 3. That is, the amplitude of the magnetic flux to be applied to the motor can be corrected using the amplitude correction amount ΔΨ according to the present disclosure. In this way, when performing the primary magnetic flux control, the motor can be preferably started or driven at a low speed.

  The present disclosure can be applied to synchronous motors such as SPMSM and IPMSM. Those synchronous motors are suitable for a heat pump refrigeration apparatus used in an air conditioner or a water heater.

DESCRIPTION OF SYMBOLS 100 Motor control apparatus 101 Duty generation part 102 Three-phase motor 103,203,303a, 303b, 403,503,603,703,803,903,1003 Motor control part 104 Inverter 105a 1st current sensor 105b 2nd current sensor 106u , W / α, β conversion unit 107 command voltage calculation unit 108 motor magnetic flux estimation unit 109 α, β / u, v, w conversion unit 111, 211a, 211b, 511, 611a, 611b, 911 phase identification unit 112 command magnetic flux identification Unit 113a α-axis magnetic flux deviation calculation unit 113b β-axis magnetic flux deviation calculation unit 114, 314a, 314b amplitude correction amount generation unit 115, 315a, 315b, 915, 1015 amplitude identification unit 116, 216a, 216b integrator 117 command magnetic flux addition unit ( Correction part)
118 Armature current deviation calculation unit 119,323 PI compensation unit 120 Base driver 121 Smoothing capacitor 122 DC power supply 123a-123f Switching element 124a-124f Free-wheeling diode 130,930 Temporary setting unit 131 Armature current specifying unit 221 Torque estimation unit 223a Speed Deviation calculation unit 223b Phase deviation calculation unit 623b Movement amount deviation calculation unit 261a High pass filter 261b Low pass filter 262 Gain multiplication unit 321a, 321b Error parameter calculation unit 322 Error parameter deviation calculation unit 518 Phase estimation unit 520, 620a, 620b, 663 Multiplication unit 542, 642a, 642b, 942 Phase addition calculation unit 919 Phase change amount generation unit 920 Speed estimation unit 921 Command torque generation unit 922 Torque deviation calculation unit

Claims (16)

A motor control device that applies a voltage vector to the three-phase motor using an inverter so that the motor magnetic flux of the three-phase motor follows a command magnetic flux vector,
A current sensor that generates a signal that is fed back from the three-phase motor and that represents a motor current flowing through the three-phase motor;
A phase specifying unit for specifying the phase of the command magnetic flux vector;
An amplitude specifying unit for specifying the amplitude of the command magnetic flux vector;
A command magnetic flux specifying unit for specifying the command magnetic flux vector using the phase of the command magnetic flux vector specified by the phase specifying unit and the amplitude of the command magnetic flux vector specified by the amplitude specifying unit; With
The amplitude specifying unit generates an amplitude correction amount using (i) a temporary setting unit for setting a temporary amplitude, and (ii) a control target amount applied to the three-phase motor specified using the signal. And (iii) a correction unit that specifies a correction amplitude larger than the temporary amplitude as the amplitude to be given to the command magnetic flux specifying unit using the amplitude correction amount. Control device.   The motor control device according to claim 1, wherein the control target amount is an amplitude of a motor current flowing through the three-phase motor.   The motor control device according to claim 1, wherein the control target amount is reactive power applied to the three-phase motor.   The amplitude correction amount generation unit specifies (a) a first inner product of a motor current flowing through the three-phase motor and the motor magnetic flux, and the speed of the three-phase motor estimated to the specified first inner product. Alternatively, the reactive power is specified by multiplying by the command speed, or (b) an axial current that represents the motor current flowing through the three-phase motor by two-phase coordinates and the three-phase motor. The motor control device according to claim 3, wherein the reactive power is specified using an axial voltage that is the voltage vector represented by the two-phase coordinates.   The motor control device according to claim 1, wherein the control target amount is a physical amount correlated with reactive power applied to the three-phase motor.   The amplitude correction amount generation unit specifies a first inner product of a motor current flowing through the three-phase motor and the motor magnetic flux, and specifies the physical quantity using the specified first inner product. The motor control apparatus described.   The amplitude correction amount generation unit specifies a second inner product of a motor current flowing through the three-phase motor and a magnet magnetic flux of a permanent magnet of the three-phase motor, and uses the specified second inner product as the physical quantity. The motor control device according to claim 5.   The motor control device according to claim 2, 3, 4, or 7, wherein the amplitude correction amount generation unit specifies the amplitude correction amount so that the specified control target amount is positive.   The motor control device according to any one of claims 1 to 8, wherein the amplitude correction amount generation unit generates the amplitude correction amount by feedback control that converges a deviation between the control target amount and a target value to zero. . The amplitude correction amount generation unit specifies the larger amplitude correction amount as the deviation obtained by subtracting the control target amount from the target value is larger,
The motor control device according to claim 9, wherein the correction unit specifies the correction amplitude that is larger as the amplitude correction amount is larger.   The phase specifying unit specifies a moving amount for each control cycle in which the phase of the motor magnetic flux should move using the command speed, and specifies the phase of the command magnetic flux vector using the specified moving amount. The motor control apparatus of any one of Claim 1 to 10.   The motor control device according to claim 11, wherein the phase specifying unit specifies the phase of the command magnetic flux vector by integrating the movement amount. The motor control device
A shaft current representing the motor current flowing through the three-phase motor in two-phase coordinates, and a shaft voltage representing the voltage vector to be applied to the three-phase motor in the two-phase coordinates; , And a motor magnetic flux estimator for estimating the motor magnetic flux applied to the three-phase motor,
A phase estimation unit that estimates the phase of the motor magnetic flux using the motor magnetic flux estimated by the motor magnetic flux estimation unit;
The motor control device according to claim 11, wherein the phase identification unit identifies the phase of the command magnetic flux vector using the phase of the motor magnetic flux estimated by the phase estimation unit and the movement amount. .   The phase specifying unit (p) corrects the command speed using the estimated vibration component of the motor torque, specifies the movement amount using the corrected command speed, and determines the specified movement amount. (Q) identifying the amount of movement using the command speed, correcting the identified amount of movement using a vibration component of the estimated motor torque, The phase of the command magnetic flux vector is specified using the corrected amount of movement, or (r) the amount of movement is specified using the command speed, and the command magnetic flux vector is used using the specified amount of movement. The motor control device according to claim 11, wherein the phase of the motor is specified, and the specified phase is corrected using a stationary component of the estimated motor torque. The motor control device
Applying the voltage vector to the three-phase motor using the inverter so that the motor magnetic flux and the motor torque of the three-phase motor follow the command magnetic flux vector and the command torque;
A shaft current representing the motor current flowing through the three-phase motor in two-phase coordinates, and a shaft voltage representing the voltage vector to be applied to the three-phase motor in the two-phase coordinates; , And a motor magnetic flux estimator for estimating the motor magnetic flux applied to the three-phase motor,
A torque estimator for estimating the motor torque from the shaft current and the estimated motor magnetic flux;
A speed estimator for estimating the speed of the three-phase motor from the estimated phase of the motor magnetic flux;
A command torque generator for generating the command torque from the command speed and the estimated speed,
The phase specifying unit specifies a moving amount for each control cycle in which the phase of the motor magnetic flux should move using a torque deviation between the command torque and the estimated motor torque, and the specified moving amount The motor control device according to any one of claims 1 to 10, wherein the phase of the command magnetic flux vector is specified using the estimated phase of the motor magnetic flux. A generator control device that applies a voltage vector to the three-phase generator using a converter so that the generator magnetic flux of the three-phase generator follows a command magnetic flux vector,
A current sensor for generating a signal fed back from the three-phase generator and representing a generator current flowing through the three-phase generator;
A phase specifying unit for specifying the phase of the command magnetic flux vector;
An amplitude specifying unit for specifying the amplitude of the command magnetic flux vector;
A command magnetic flux specifying unit for specifying the command magnetic flux vector using the phase of the command magnetic flux vector specified by the phase specifying unit and the amplitude of the command magnetic flux vector specified by the amplitude specifying unit; With
The amplitude specifying unit includes: (i) a temporary setting unit for setting a temporary amplitude; and (ii) an amplitude correction amount using a control target amount applied to the three-phase generator specified using the signal. An amplitude correction amount generation unit to generate, and (iii) a correction unit that specifies a correction amplitude larger than the temporary amplitude as the amplitude to be given to the command magnetic flux specifying unit using the amplitude correction amount, Generator control device.

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