KR20000046679A - Method and apparatus for controlling speed of synchronous reluctance motor - Google Patents

Abstract

The present disclosure relates to a speed control apparatus of a synchronous reluctance motor that smoothly controls the speed and torque of a motor by calculating the position of the rotor as detection of voltage and current flowing in each phase of the motor without a rotor position sensor.

The disclosed speed control device includes: voltage / current detection means for detecting current and voltage flowing in each phase of a motor; Coordinate conversion means for converting the detected voltage and current into magnetic flux voltage, current and torque voltage, and current of the rotary coordinate system; Speed estimation value calculating means for calculating the speed estimation value of the motor according to the inductance of the rotational coordinate system with the coordinate flux flux / torque voltage, current, and estimating the speed command value; A flux angle calculating means for integrating the calculated speed estimate value to obtain the position of the rotor and supplying the obtained rotor position information to the coordinate converting means and the voltage generating means,

Accordingly, in a control system requiring precise control such as vector control, there is an advantage in that the speed of the motor can be smoothly controlled without a position sensor in a place where low cost and rotor position detection such as a compressor are required.

Description

Method and device for speed control of synchronous reluctance motor

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a speed control method of a reluctance motor such as a synchronous motor. Specifically, among the speed control methods of a synchronous reluctance motor that generates torque of a motor using a difference in magnetoresistance, in particular, The present invention relates to a speed control method and apparatus for a synchronous reluctance motor for controlling the speed and torque of a motor using only the input voltage and current of the motor without a sensor for detecting the position of the rotor.

For example, synchronous reluctance motors are generally simpler in construction and economical than conventional inductive and synchronous motor drive systems. In addition, the converter for applying power to the synchronous reluctance motor requires a small power device, which is more economical and reliable.

In view of these advantages, the drive system of a synchronous reluctance motor provides an effect different from that of a conventional drive system, and is also widely used in industrial applications.

Synchronous relucton motors typically have multiple poles or teeth for both the stator and the rotor. The stator phase has phase windings, but the rotor phase has no windings or magnets at all. Each pair of stator poles are connected in series to form an independent phase of a multiphase synchronous reluctance motor.

When the current in each phase winding is switched on in a predetermined order synchronized to the rotor as an angular position, torque is generated, and along this, a magnetic force is generated between the rotor and stator poles in close proximity to each other. . The current is switched off in each phase before the rotor pole closest to the stator pole rotates past its aligned position.

If this is not the case, the magnetic force may produce negative or breaking torque. The torque generated in this way is independent of the direction of current movement so that unidirectional current pulses synchronized with rotor motion can be applied to the stator phase winding by a converter using a unidirectional current switching means such as a thyristor or transistor. Is formed.

A synchronous reluctance motor operates by switching on or off the stator field current in synchronization with the rotor position.

By appropriately positioning the ignition pulses with respect to the rotor angle, electrostatic or reversal operations and motoring or generating operations can be obtained. Typically, the desired phase current rectification is achieved by feeding back the rotor position signal from a position detection sensor such as an encoder and Hall IC to the controller.

As an example of the drive system of the conventional synchronous motor as described above, the speed control device of the synchronous reluctance motor is shown in FIGS.

The synchronous reluctance motor includes a stator 10 and a rotor 11.

As shown in Fig. 2, the rotor 11 is provided with a groove 11a for different magnetoresistance between the D-axis and the Q-axis.

The stator 10 of the synchronous reluctance motor has the same structure as a conventional induction motor.

Torque generation of the synchronous reluctance motor is caused by the magnetoresistance component, and the rotor 11 rotates about the stator 10 by pure magnetoresistance torque.

The speed control device for controlling the speed of such a synchronous reluctance motor is shown in FIG.

The speed control device of the synchronous reluctance motor is provided with a rotor and a stator to detect the position of the motor 100 rotating by magnetoresistive torque and the rotor 11 of the motor 100 to output a rotation speed. A rotor comparator 102, a first comparator 102 for comparing the detected speed with a speed command value input from the input terminal 115 to obtain an error of speed, and a rotation coordinate system according to the obtained error of speed. A first speed detection unit 103 for generating torque-minute current command value iqs ^* and a first and second phase currents ias and ics of the stationary coordinate system supplied to the stator 10 of the motor 100, respectively. And a magnetic flux angle calculation unit for obtaining an angle between the stationary coordinate system and the rotational coordinate system, that is, the position θ of the rotor 11, from the speeds detected by the second current detection elements 106 and 107 and the rotor position detector 108. 109 and the position of the detected stop coordinate system according to the position of the rotor 11 Coordinate transformation unit 110 for converting the currents of the A and C phases into the rotational coordinate system to generate the magnetic flux currents (ids) of the rotational coordinate system and the torque currents (iqs) of the rotational coordinate system 90 degrees behind the phase angle of the current. , once the rotor position estimation unit 108, the magnetic flux instruction for generating a magnetic flux minute current command value (ids ^*) of a rotating coordinate system in accordance with the detected speed from the generation unit 104, the magnetic flux minute current command value (ids ^*) of the rotating coordinate system, and The second comparator 111 for obtaining an error from the magnetic flux current ids of the rotary coordinate system obtained by the coordinate transformation unit 110, and the magnetic flux current command value of the rotary coordinate system having an error current with respect to the magnetic flux content of the obtained rotary coordinate system ( ids ^* ), the torque control current 112 and the torque current (iqs) of the rotation coordinate system coordinate converted by the coordinate conversion unit 110 and the torque current command value (iqs) of the rotation coordinate system input from the speed controller 103. ^And the third comparator 105 to find the error with , The magnetic flux current command value ids ^* of the rotary coordinate system input from the magnetic flux control unit 112 and the torque current command value iqs ^* of the rotary coordinate system input from the third comparator 105, respectively, the magnetic flux voltage command value Vds ^*. ) And the current control unit 113 for converting the torque-voltage voltage command value (Vqs ^* ), and the magnetic flux voltage command value (Vds ^* ) and the torque-voltage voltage command value (Vqs ^* ) are three-phase voltage command values (Vas, Vbs, Vcs). And converts into a PWM time for applying a three-phase current to the stator 10 of the motor 100 in accordance with the voltage generator 114 and the three-phase voltage command value generated by the voltage generator 114 It consists of an inverter unit 101.

Speed control of the conventional synchronous reluctance motor configured as described above will be described in detail with reference to FIGS.

First, in order to operate the synchronous reluctance motor 100 with the speed command value voltage input to the input terminal 115, the rotor position detector 108 such as an encoder or a hall element, the stator 10 as shown in FIGS. 2 and 3. And a rotor 11 to detect the rotational speed of the rotating synchronous reluctance motor 100 and provide it to the first comparator 102 such as the magnetic flux command generator 104 and the adder which will be described later.

The first comparator 102 adds the speed of the synchronous reluctance motor 100 detected and input by the rotor position detection unit 108 and the speed command value voltage input from the input terminal 115 to determine the speed of these two values. Generates an error.

The error of the velocity obtained above is generated as the torque-minute current command value iqs * of the rotational coordinate system in the speed controller 103.

The magnetic flux command generation unit 104 generates a magnetic flux current command value ids * of the rotary coordinate system by distinguishing the positive torque region and the constant output region with the speed input from the rotor position detection unit 108.

That is, as is well known, the torque generation of the synchronous reluctance motor 100 is caused by the magnetoresistance component, and is purely rotated by the magnetoresistance torque.

2 and 3, it can be seen that the stator 10 of the synchronous reluctance motor 100 has the same structure as the induction motor. In the case of the rotor 11, the groove 11a is provided in order to vary the reluctance of the magnetic flux expressed by the rotational coordinate system, that is, the D-axis and the torque, that is, the Q-axis.

Therefore, in order to control the speed, the position of the rotor must be known, and in order to know the position of the rotor, as shown in FIG. 3, the positions of the D-axis and the Q-axis must be known at each phase of the winding of the stator 10 of FIG. 2. do.

The torque equation of the synchronous reluctance motor 100 as described above is expressed by Equation (1).

As can be seen from the above equation, the torque of the synchronous reluctance motor 100 is the product of the difference between the reluctance represented by Ld and Lq and the component of the current of the stator 10, which is the flux current ids and the torque current iqs. Will appear.

As shown in FIG. 3, the D-axis (magnetic flux) of the rotor 11 is taken as the axis | shaft through which a magnetic flux flows mainly, and the Q-axis (torque_ torque) is an axis electrically 90 degree ahead of D-axis. Since this is for a four-pole rotor, the electrical 90 degrees are mechanically equivalent to 45 degrees, so that the D and Q axes are displayed as shown in FIG.

4 shows a vector of current versus voltage applied to the stator 10 of the synchronous reluctance motor 100.

The stator current is is formed with a constant delay angle with respect to the stator voltage Vs.

At this time, if the stator current is projected on the D axis and the Q axis indicated by the rotational coordinate system, as shown in FIG. 4, the torque about the flux current ids about the D axis and the Q axis among the components of the stator 10 current are shown. The minute current iqs can be obtained, which causes the stator current component to generate torque in Equation (1).

The torque of the motor 100 in Equation 1 is represented by the product of the flux current and the torque current, and the current is is formed with a constant delay angle with respect to the stator voltage Vs.

Therefore, in order to control the speed of the motor 100, the stator voltage Vs may be controlled, and a current is generated by the stator voltage to generate torque of the motor 100.

Among the stator current components, the magnetic flux current ids is a part related to the magnetic flux of the motor 100. Therefore, in order to smoothly control the motor 100 at both low speed and high speed, that is, weak field control is required to reduce the flux current of the motor at high speed.

Subsequently, as described above, according to the speed of the synchronous reluctance motor 100 in the vector control inverter controlled by the speed control unit 103 and the magnetic flux command generation unit 104 separately to the magnetic flux and torque components of the rotary coordinate system. The torque component current command value iqs * of the rotational coordinate system generated by the speed controller 103 of 1 is provided to the second comparator 105, and the magnetic flux component current command value of the rotational coordinate system generated by the magnetic flux command generation unit 104 ( ids *) is provided to the third comparator 111.

Meanwhile, the first and second current detection elements 106 and 107 detect a current supplied to each phase of the stator 10 of the synchronous reluctance motor 100, for example, the A phase and the C phase, respectively, and coordinate conversion unit. Supply to (110).

The magnetic flux angle calculating section 109 integrates the speed detected by the rotor position detecting section 108 to obtain an angle between the stationary coordinate system and the rotor coordinate system, that is, the position θ of the rotor 11. Accompanied by the coordinate transformation unit 110 coordinate-converts the currents of the A and C phases of the stationary coordinate system detected by the first and second current detection elements 106 and 107 according to the position θ of the rotor 11. As shown in Fig. 4, the magnetic flux current of the stator D-axis component and the torque current of the stator Q-axis component, that is, the magnetic flux currents (ids) and the torque current (iqs) of the D-axis and Q-axis indicated by the rotational coordinate system are generated. .

The torque component current iqs of the stator Q axis is provided to the second comparator 105 such as an adder, and the magnetic flux component ids of the stator D axis is provided to the third comparator 111.

The second comparator 105 is a torque coordinate current input from the coordinate transformation unit 110, that is, torque current (iqs) represented by the Q axis and torque torque current command value (iqs *) of the rotation coordinate system input from the speed controller 103. ) Is obtained and provided to the current control unit 113.

In addition, the third comparator 111 also transforms the coordinates from the magnetic flux command generation unit 104 according to the speed of the synchronous reluctance motor 100 and the flux current command value ids * of the rotor table system and the coordinate transformation unit 110. The error from the magnetic flux component (D-axis) current (ids) of the rotated coordinate system is calculated. By the error current, the magnetic flux control unit 112 controls the magnetic flux current command value ids * of the rotational coordinate system and provides it to the current control unit 113.

The current controller 113 uses the magnetic flux component current command value ids * of the rotary coordinate system controlled by the magnetic flux controller 112 and the torque component current command value iqs * of the rotary coordinate system obtained by the second comparator 105, respectively. The voltage generator 114 generates three-phase voltage command values Va, Vbs, and Vcs in accordance with the magnetic flux and the torque voltage command value, which are converted into the command value Vds * and the torque-voltage voltage command value Vqs *.

In order to apply the three-phase current to the stator 10 of the synchronous reluctance motor 100 in accordance with the three-phase voltage command value generated in this way, the inverter unit 101 is pulse width modulated (PWM) to the synchronous reluctance motor 100. Is operated at the speed command value described above.

The speed control apparatus for a synchronous reluctance motor according to the related art described above detects a speed by using an encoder or a hall element in order to know information about a rotor position, and the detected speed is a rotor in a flux angle calculator for coordinate transformation. It is calculated as the position of, and compared with the speed command value it can be seen that the speed control unit to control the speed.

However, the speed control device of the conventional synchronous reluctance motor as described above requires the rotor position sensor and the two current sensors to control the speed of the motor through the vector control.

Therefore, the use of a rotor position sensor for knowing the rotor position of a synchronous reluctance motor leads to an increase in price, and in particular in the case of a compressor of a refrigerator or an air conditioner, it is difficult to install the rotor position sensor therein. Follow.

In addition, as one method of avoiding the increase in the complexity and cost of the circuit generated by the vector control method, it is conceivable to monitor the terminal voltage of the motor indirectly to detect the rotor position, but it is monitored by the waveform detection method. Not only does it have to be difficult, it is not reliable at low speed of the motor, and there is a problem that it does not operate at zero speed.

Therefore, a smaller drive in cost and a larger drive in reliability are required. In order to reduce the size, the complexity of the circuit, and the increase in price in all these drives, the rotor position sensor described above is required. Most preferably removed.

Accordingly, the present invention excludes the difficulty of installation and the increase in cost caused by the application of the rotor position sensor in the above-described prior art, and in one aspect of the present invention, detects the current and voltage flowing in each phase of the motor. It is an object of the present invention to provide a speed control method and apparatus for a synchronous reluctance motor to smoothly control the speed and torque of the motor.

1 to 4 is a view showing a configuration provided for the description of the synchronous reluctance motor according to the prior art,

1 is a block diagram provided for explaining the speed control device of the synchronous reluctance motor;

2 is a cross-sectional view of the synchronous reluctance motor,

3 is a cross-sectional view showing a rotor of the synchronous reluctance motor in FIG.

FIG. 4 is a diagram illustrating a vector of current with respect to a voltage applied to the synchronous reluctance motor of FIG. 1.

5 is a configuration diagram provided for explaining the speed control device of the synchronous reluctance motor according to the present invention,

6 is a curve diagram illustrating a change in inductance of the synchronous reluctance motor of FIG. 5,

FIG. 7 is a block diagram illustrating in detail the speed estimating unit of FIG. 5.

<Description of the code | symbol about the principal part of drawing>

100: motor 101: inverter unit

102: first comparator 104: magnetic flux command generation unit

105: second comparator 106, 107: first, second current detecting element

109: magnetic flux angle calculation unit 200: voltage detection unit

201: coordinate conversion unit 202: speed estimation value calculation unit

202a: induced voltage calculator 202b: inductance calculator

202c: induced voltage estimating unit 202e: proportional integral control unit

Speed control method of a synchronous reluctance motor according to an aspect of the present invention for achieving the above object, the speed command value to the actual motor speed in the motor having a plurality of stator phases excited in synchronization with the rotor position In the following control method:

(1) extracting a current and a voltage flowing in each phase of the motor and converting the coordinates into a magnetic flux / torque voltage and a current of a rotational coordinate system;

(2) obtaining a voltage induced by the actual motor with the magnetic flux voltage, the current and torque voltage, and the current of the rotary coordinate system;

(3) determining the position of the rotor by obtaining a change amount of the two inductances using the magnetic flux and torque currents of the rotary coordinate system;

(4) obtaining an induced voltage estimate of the motor from the change in inductance;

(5) calculating an error value by comparing the actual induced voltage of the motor with the estimated induced voltage; And

(6) proportionally integrating the error value to obtain a speed estimate of the motor and causing the obtained speed estimate to estimate the speed command value.

Further, according to the speed control apparatus of the synchronous reluctance motor of the present invention, in a motor having a plurality of stator phases excited in synchronization with the rotor position, the current flowing in each phase of the motor and the actual speed of the motor are detected. In a device that controls the speed of a motor:

Voltage / current detection means for detecting current and voltage of the fixed coordinate system flowing in each phase of the motor;

Coordinate conversion means for converting the voltage and current of the fixed coordinate system detected by the voltage / current detection means into coordinates of magnetic flux voltage, current and torque voltage, and current of the rotor magnetometer and outputting the coordinates;

Speed estimation value calculating means for obtaining the speed estimation value of the motor according to the inductance of the rotational coordinate system having the magnetic flux voltage, the current and torque voltage, and the current converted by the coordinate conversion means, and estimating the speed command value; And

And a magnetic flux angle calculating means for integrating the speed estimation value obtained by the speed estimation value calculating means to obtain the position of the rotor and supplying the obtained rotor position information to the coordinate conversion means and the voltage generating means.

In the speed control apparatus of the synchronous reluctance motor, the speed estimate value calculating means includes:

(1) an induced voltage calculating means for calculating a voltage actually induced in the motor with magnetic flux voltage, current and torque voltage, and current of the rotary coordinate system obtained by the coordinate converting means;

(2) inductance calculating means for calculating an amount of change in inductance from the magnetic flux current and the torque current of the rotary coordinate system obtained by the coordinate conversion means;

(3) an induced voltage estimation calculating means for calculating an induced voltage estimate of the motor according to the calculated inductance change amount;

(4) comparison means for generating an error value by comparing the induced voltage estimate with an actual induced voltage of the motor; And

(5) Proportional integration control means for estimating the speed estimation value by proportionally integrating the error value obtained by the comparison means and estimating the obtained speed estimation value to the variation amount of the inductance and the speed command value.

In this way, the voltage and current of the fixed coordinate system flowing in each phase of the motor can be detected without using the rotor position sensor to know the rotor position information of the motor, and the amount of inductance change of the rotating coordinate system is obtained and the change amount is used to determine the rotor position. It can be seen that the speed of the motor is calculated by calculating the speed estimate for the speed command value.

As a result, in a control system requiring precise control such as vector control, it is possible to smoothly control the speed of the synchronous reluctance motor at low cost, and also has the advantage of eliminating the difficulty of installing the rotor position sensor.

And, there may be a plurality of embodiments of the present invention, the following will be described in detail for the most preferred embodiment.

Through this preferred embodiment, the objects, other objects, features and advantages of the present invention will become more apparent from the following description with an embodiment according to the present invention in connection with the accompanying drawings shown for illustrative purposes.

Hereinafter, with reference to the accompanying drawings will be described in detail a preferred embodiment of the method and apparatus for controlling the speed of a synchronous reluctance motor according to the present invention.

In addition, the technique of the present invention can be applied to various motor control systems such as inductive and synchronous motors.

In addition, in each figure used for description, the same component may be attached | subjected, and may show the same number, and the overlapping description may be abbreviate | omitted.

In addition, the following description considers an example of a synchronous reluctance motor having a large number of magnetic poles or teeth for both the stator and the rotor and generating torque by the magnetoresistive component.

5 is a configuration diagram provided for explaining the speed control device of the synchronous reluctance motor according to the present invention.

Speed control apparatus according to the present embodiment, the stator 10 and the rotor 11 is provided with a motor 100 and the motor 100 to rotate by the voltage, current of each phase provided from the inverter unit 101, First and second current detecting elements 106 and 107 for detecting currents (ias and ics) of the A and C phases of the stationary coordinate system supplied to the stator 10 of the stator 10, and the stator 10 of the motor 100, respectively. The voltage detection unit 200 which detects the voltages Va and Vcs of the A and C phases supplied thereto, and the current (ias) of the A and C phases of the detected stationary coordinate system according to the position θ of the rotor 11. , ics) by converting the magnetic flux current ids of the rotary coordinate system and the torque component current iqs of the rotary coordinate system 90 degrees behind the phase angle of the current to convert the magnetic flux current ids into a third comparator 111. The voltages Va and Vcs of the A and C phases of the stationary coordinate system detected by the coordinate converting unit 110 and the voltage detecting unit 200 are supplied to the second comparator 105. rotation Coordinate transformation unit 201 for coordinate transformation into magnetic flux voltage Vds and torque voltage Vqs of the system, and magnetic flux current, voltages ids, Vds, torque torque current, and voltage of the coordinate coordinate system. a speed estimation value calculating unit 202 for obtaining the speed estimation value Wr # of the motor according to the inductance of the rotational coordinate system with (iqs, Vqs) and providing it to the magnetic flux command generation unit 104 and the first comparator 102; It is composed of a magnetic flux angle calculation unit 109 which obtains the angle between the stationary coordinate system and the rotational coordinate system, that is, the position of the rotor 11, from the velocity estimation value Wr # and provides it to the coordinate conversion unit 110 and the voltage generator 114. do.

As shown in Fig. 7, the speed estimator 202 calculates the flux current, the voltages ids, Vds, the torque current, and the voltage of the rotational coordinate system inputted by the coordinate conversion units 110 and 201. Induction voltage calculation unit 202a for calculating the voltage induced in the actual motor 100 with (iqs, Vqs), and magnetic flux current ids and torque of the rotational coordinate system inputted by the coordinate conversion unit 110. An inductance calculator 202b for calculating the change in inductance of the rotational coordinate system with the minute current iqs, an organic voltage estimation calculator 202c for calculating the induced voltage estimate of the motor 100 with the change in inductance, and the induced voltage A fourth comparator 202d for generating an error value by comparing the estimated voltage with the induced voltage of the actual motor 100 and a speed estimating value Wr # are obtained by proportionally integrating the obtained error value. 202b) It provides a proportional integral control unit 202e.

The speed control device of the synchronous reluctance motor of the present invention made as described above will be described in more detail with reference to FIGS. 5 and 7.

First, in order to operate the synchronous reluctance motor 100 at the speed command value Wr * inputted to the input terminal 115, the first and second current detecting elements 106 and 107 such as the current transformer are stator 10. And the rotor 11, the current of each phase of the motor 100 rotating under the control of the inverter unit 101, that is, the currents of the phases A and C of the three phases flowing through the stator 10 (ias, ics). Is detected and provided to the coordinate transformation unit 110.

The voltage detector 200 detects the voltages Va and Vcs of the A and C phases of the stationary coordinate system supplied to the stator 10 of the synchronous reluctance motor 100 and provides them to the coordinate converter 201.

The coordinate transformation unit 110 is detected by the first and second current detection elements 106 and 107 according to the position θ of the rotor 11 obtained from the magnetic flux angle calculation unit 109 to be described later. Coordinate transformation of the currents (ias, ics) of the A and C phases of the stationary coordinate system, the magnetic flux current of the stator D-axis component and the torque component current of the stator Q-axis component as shown in FIG. The magnetic flux component current ids and the torque component current iqs of the shaft are generated and provided to the speed estimation calculator 202.

In addition, the other coordinate conversion unit 201 coordinates the voltages Va and Vcs of the stationary coordinate system inputted from the voltage detector 200 with the magnetic flux voltage voltage Vds and the torque voltage voltage Vqs of the rotary coordinate system. The conversion is provided to the speed estimating unit 202.

The speed estimating unit 202 has a speed estimating value for the speed command value Wr * with the flux current, the voltage ids and Vds and the torque current and the voltage iqs and Vqs of the rotating coordinate system inputted by the coordinate transformation. Wr #)

That is, the speed estimating value calculating section 202 described above includes the induced voltage calculating section 202a, the inductance calculating section 202b, the induced voltage estimating calculating section 202c, the fourth comparator 202d and the proportional integral control section 202e. ).

Therefore, the induced voltage calculating unit 202a of the speed estimating unit 202 is coordinate transformed into a two-phase equivalent D-axis and Q-axis, that is, the magnetic flux component (D-axis) current, voltages (ids, Vds) and torque of the rotational coordinate system. The induced voltage em of the actual motor 100 is calculated and provided to the fourth comparator 202d using the minute (Q-axis) current and the voltages iqs and Vqs.

In addition, the inductance calculating unit 202b has only the magnetic flux component (D-axis) current (ids) and the torque component (Q-axis) current (iqs) of the rotating coordinate system in the coordinate transformation unit 110, and the inductance Ld, Lq) is calculated and provided to the induced voltage estimation calculator 202c.

As shown in FIG. 6, the inductance of the synchronous reluctance motor is changed when the rotor 11 of the motor 100 rotates, and the inductance Ld and Lq change depending on the rotation angle. When the inductance change of the axis and the Q axis is calculated by detecting voltages Vas and Vqs and currents ids and iqs input to the stator 10 of the motor 100, the position of the rotor can be known. By using the amount of inductance, it is possible to control the rotor speed of the motor 100.

In the vector representing the relationship between the rotor position, voltage, and current of FIG. 4, the voltage equation of the synchronous reluctance motor is expressed by Equations 2 and 3.

Vds = rsids + d (λds) / dt-ωr λqs

Vqs = rsiqs + d (λqs) / dt-ωr λds

Here, Vds and Vqs are stator voltages of D and Q axes, rs is stator resistance, ids and iqs are D-axis, stator current of Q-axis, λds, λqs is D-axis, Q-axis flux, and ωr is the rotor of the motor. Speed.

Since λds = Ldis and λqs = Lqis, voltage and current can be detected to calculate Ld and Lq, which are inductances of the D-axis (magnetic flux) and Q-axis (torque).

This calculated amount of change corresponds to the position of the rotor 11 of the motor 100 of FIG. 3 and the amount of change is shown in FIG. 6.

Subsequently, the above-described change amounts of the inductances Ld and Lq calculated by the inductance calculating unit 202b are calculated by the induced voltage estimation calculating unit 202c as the induced voltage estimation value em # of the motor 100 and output.

The fourth comparator 202d is an induced voltage em of the actual motor 100 calculated by the induced voltage calculator 202a and an induced voltage estimated value em # of the motor 100 calculated by the induced voltage estimation calculator 202c. The difference value, that is, the error value, is obtained and provided to the proportional integral controller 202e.

The proportional integral controller 202e proportionally integrates the error value calculated by the fourth comparator 202d to obtain a speed estimation value Wr # for estimating the speed command value Wr * of the motor 100.

The velocity estimation value Wr # thus obtained is input to the inductance calculating unit 202b to continuously estimate the inductance variation, and is also provided to the magnetic flux angle calculating unit 109, the magnetic flux command generating unit 104, and the first comparator 102. do.

The magnetic flux angle calculation unit 109 integrates the speed estimate value Wr # calculated by the speed estimation value calculation unit 202 to obtain an angle between the stationary coordinate system and the rotational coordinate system, that is, the position θ of the rotor 11 described above. In response to this, the coordinate conversion unit 110 displays the currents of the phases A and C of the stationary coordinate system detected by the first and second current detection elements 106 and 107 in the rotational coordinate system according to the position of the rotor 11. The coordinates are converted into the flux currents ids and the torque currents iqs of the D and Q axes.

The first comparator 102 compares the speed estimating value Wr # calculated by the speed estimating value calculating unit 202 with the speed command value Wr * inputted from the input terminal 115 to generate an error in speed for these two values. do.

The error of the speed obtained above is generated as the torque-minute current command value iqs * of the rotational coordinate system in the speed controller 103 and compared with the torque-current current iqs in the second comparator 105 to be provided to the current controller 113. do.

The flux command generator 104 generates the flux current command value ids * of the rotary coordinate system by distinguishing the constant torque area from the constant torque area with the input speed estimate value Wr #, and the current command value ids *. ) Is compared to the magnetic flux current ids of the rotary coordinate system in the third comparator 111 and is provided to the current controller 113 through the magnetic flux controller 112.

Accordingly, the current control unit 113 sets the magnetic flux component (D-axis) current command value (ids *) and torque component (Q-axis) current command value (iqs *) of the rotary coordinate system, respectively, the magnetic flux component voltage command value (Vds *) and torque component voltage. The voltage generator 114 generates three-phase voltage command values Vas, Vbs and Vcs by converting the command value Vqs * and the magnetic flux and torque voltage command values to generate a synchronous reluctance motor through the inverter unit 101. 100 is operated at the speed command value Wr * described above.

In this way, the speed estimation value for the speed command value of the rotor can be obtained by using the inductance change of the magnetic flux component (D axis) and the torque component (Q axis), and the speed of the motor can be smoothly compared with the speed estimate value. Can be controlled.

On the other hand, as a comparative example, in order to know information about the rotor position of a conventional technology, that is, a synchronous reluctance motor, the speed is detected using a rotor position sensor such as an encoder or a hall element and the detected speed is obtained. Unlike calculating the position of the rotor, the present invention, without the rotor position sensor, detects the voltage and current of the fixed coordinate system flowing in each phase of the stator, obtains the amount of change in inductance of the rotary coordinate system and uses the change amount to determine the speed of the rotor It can be seen that the speed of the motor is controlled by calculating the speed estimate for the setpoint.

As a result, according to the present invention, it is possible to control the speed and torque of the motor at low cost in a control system requiring precise control such as vector control, and also without a position sensor in a place requiring rotor position detection such as a compressor. There is an advantage to control the speed of the motor.

As described above, in the present embodiment, only the voltage and current flowing on each stator of the motor are used to calculate the amount of change in inductance of the rotary coordinate system, and by using the calculated amount of change to control the speed and torque of the motor, the existing rotor position is obtained. There is no increase in the price caused by the use of the sensor, it is possible to exclude the difficulty of the installation of the position sensor.

According to this application example, it is possible to smoothly control the speed and torque even in a structure such as a compressor used for a refrigerator or an air conditioner by detecting only the current and voltage flowing in each phase of the motor to control the speed of the motor.

In addition, although specific embodiments of the present invention have been described and illustrated above, it is obvious that the present invention may be variously modified and implemented by those skilled in the art.

Such modified embodiments should not be individually understood from the technical spirit or the prospect of the present invention, and such modified embodiments should fall within the appended claims of the present invention.

It is clear from the above description that, according to the speed control apparatus of the synchronous reluctance motor according to the present invention, by controlling the speed and torque of the motor by detecting the current and voltage flowing in each phase of the motor without using the rotor position sensor. In addition, there is an effect that the speed control of the motor is smoothly performed even in a place where it is difficult to detect the rotor position such as a refrigerator and an air conditioner compressor.

Claims (3)

A method of controlling the actual motor speed in accordance with a speed command value in a motor having a plurality of stator phases excited in synchronization with the rotor position: (1) extracting a current and a voltage flowing in each phase of the motor and converting the coordinates into a magnetic flux / torque voltage and a current of a rotational coordinate system; (2) obtaining a voltage induced by the actual motor with the magnetic flux voltage, the current and torque voltage, and the current of the rotary coordinate system; (3) determining the position of the rotor by obtaining a change amount of the two inductances using the magnetic flux and torque currents of the rotary coordinate system; (4) obtaining an induced voltage estimate of the motor from the change in inductance; (5) calculating an error value by comparing the actual induced voltage of the motor with the estimated induced voltage; And And (6) calculating the speed estimate of the motor by proportionally integrating the error value and causing the obtained speed estimate to estimate the speed command value. A device for controlling the speed of a motor by detecting a current flowing in each phase of the motor and an actual speed of the motor in a motor having a plurality of stator phases excited in synchronization with the rotor position: Voltage / current detection means for detecting current and voltage of the fixed coordinate system flowing in each phase of the motor; Coordinate conversion means for converting the voltage and current of the fixed coordinate system detected by the voltage / current detection means into magnetic flux voltage, current and torque voltage, and current of the rotor magnetometer; Speed estimation value calculating means for obtaining the speed estimation value of the motor according to the inductance of the rotational coordinate system having the magnetic flux voltage, the current and torque voltage, and the current converted by the coordinate conversion means, and estimating the speed command value; And A synchronous reluctance motor, comprising a flux angle calculating means for integrating the speed estimate obtained by the speed estimating means to obtain the position of the rotor and supplying the obtained rotor position information to the coordinate converting means and the voltage generating means. Speed control device. The method of claim 2, The speed estimation value calculation means, (1) an induced voltage calculating means for calculating a voltage actually induced in the motor with magnetic flux voltage, current and torque voltage, and current of the rotary coordinate system obtained by the coordinate converting means; (2) inductance calculating means for calculating an amount of change in inductance from the magnetic flux current and the torque current of the rotary coordinate system obtained by the coordinate conversion means; (3) an induced voltage estimation calculating means for calculating an induced voltage estimate of the motor according to the calculated inductance change amount; (4) comparison means for generating an error value by comparing the induced voltage estimate with an actual induced voltage of the motor; And (5) a proportional integral control means for estimating the speed estimation value by proportionally integrating the error value obtained by the comparing means and estimating the obtained speed estimation value to the variation amount of the inductance and the speed command value. Speed control device.