JP5888148B2 - Rotating machine control device - Google Patents

Description

  The present invention includes a switching element that selectively connects a terminal of the rotating machine to each of a positive electrode and a negative electrode of a DC voltage source, and a diode connected in reverse parallel to the switching element, in order to control a control amount of the rotating machine. The present invention relates to a control device for a rotating machine that operates a DC / AC conversion circuit.

  For example, in Patent Document 1 below, an inverter connected to a motor is operated in order to feedback-control a detected value of a current flowing through the motor to a command value using a current required to generate a desired torque as a current command value. What to do is described.

Japanese Patent No. 4736805

  By the way, in the case of the above technique, even if the desired torque is zero, a command value for the current required to make the torque zero is set, and the detected value of the current flowing through the motor is set to zero. In general, feedback control is performed to a command value for the purpose. However, if the current realized by the feedback control does not constantly become zero, there is a possibility that the power utilization efficiency is lowered due to the switching loss of the switching element of the inverter.

  The present invention has been made in the process of solving the above-mentioned problems, and its purpose is to selectively connect the terminals of the rotating machine to the positive electrode and the negative electrode of the DC voltage source in order to control the control amount of the rotating machine. The object is to provide a control device for a new rotating machine that operates a DC / AC conversion circuit including a switching element to be connected and a diode connected in reverse parallel to the switching element.

  Hereinafter, means for solving the above-described problems and the operation and effect thereof will be described.

The first invention is a switching element (S ¥ #) that selectively connects a terminal of the rotating machine to each of a positive electrode and a negative electrode of a DC voltage source (12) in order to control a control amount of the rotating machine (10). And an operating means (20) for operating a DC / AC converter circuit (INV) including a diode (D ¥ #) connected in reverse parallel to the switching element, wherein the operating means outputs an output voltage of the DC / AC converter circuit. An on-mode control means for turning on / off the switching element of the DC / AC converter circuit so that the torque of the rotating machine is equal to or less than a specified value; and In order to control the off-mode control means and the torque of the rotating machine below the specified value, the control of the on-mode control means is adopted or the control of the off-mode control means is controlled. A switching means for one of the switching process to use, characterized in that it comprises a.

  When the torque is controlled below the specified value by the on-mode control means, when a current is flowing through the rotating machine, a switching loss is generated as the switching state of the switching element is switched. On the other hand, according to the control of the off-mode control means, no switching loss or the like occurs, but when the rotating speed of the rotating machine increases, a current that causes load torque to the rotating machine may flow through the diode. . In this regard, in the above invention, by providing the switching means, it is possible to achieve both the reduction of loss and the suppression of load torque.

  In addition, about the expansion of the concept regarding the following typical embodiment concerning this invention, it describes in the column of "other embodiment" after typical embodiment.

1 is a system configuration diagram according to a first embodiment. FIG. The flowchart which shows the procedure of the switching process of the torque zero control concerning the embodiment. The system block diagram concerning 2nd Embodiment. The flowchart which shows the procedure of the switching process of the torque zero control concerning the embodiment. The flowchart which shows the procedure of the switching process of the torque zero control concerning 3rd Embodiment.

<First Embodiment>
Hereinafter, a first embodiment in which a control device for a rotating machine according to the present invention is applied to a control device for a rotating machine as an in-vehicle main machine will be described with reference to the drawings.

  A rotating machine (motor generator 10) shown in FIG. 1 is an on-vehicle main machine, and is mechanically coupled to drive wheels (not shown). In the present embodiment, an embedded magnet synchronous machine (IPMSM) is assumed as the motor generator 10.

  The motor generator 10 is connected to the high voltage battery 12 via the inverter INV. The inverter INV includes three sets of series connection bodies of switching elements S ¥ p, S ¥ n (¥ = u, v, w), and the connection points of these series connection bodies are U, V, Each is connected to the W phase. As these switching elements S ¥ # (¥ = u, v, w; # = n, p), an insulated gate bipolar transistor (IGBT) is used in this embodiment. In addition, a diode D ¥ # is connected in antiparallel to each of these.

  In the present embodiment, the following is provided as detection means for detecting the state of the motor generator 10 and the inverter INV. First, a voltage sensor 14 that detects an input voltage (power supply voltage VDC) of the inverter INV is provided. Further, a current sensor 16 that detects currents iv and iw flowing through the V-phase and W-phase of motor generator 10 is provided. Furthermore, a rotation angle sensor 18 for detecting the rotation angle (electrical angle θ) of the motor generator 10 is provided.

  Detection values of the various sensors are taken into the control device 20 via an interface (not shown). The control device 20 generates and outputs an operation signal for operating the inverter INV based on the detection values of these various sensors. Here, the signal for operating the switching element S ¥ # of the inverter INV is the operation signal g ¥ #.

  Specifically, the currents iv and iw detected by the current sensor 16 are the d-axis current id and the q-axis current, which are components of an orthogonal two-dimensional rotational coordinate system having the field direction as the d-axis in the dq converter 22. converted to iq.

  On the other hand, in current command value setting unit 24, torque command value Trq * for motor generator 10, power supply voltage VDC, and electrical angular velocity ω obtained by time differentiation of electrical angle θ are input, and d-axis current command value is set. Set id * and q-axis current command value iq *. Here, in the current command value setting unit 24, basically, the torque command value Trq * is input, and the current required for realizing the minimum current / maximum torque control is set as the current command values id * and iq *. . However, if it is assumed that it is difficult to perform the minimum current / maximum torque control based on the power supply voltage VDC and the electrical angular velocity ω, the current command value is set so as to perform the field weakening control by flowing a current in the negative direction of the d-axis. Set id * and iq *. In particular, in the present embodiment, when the torque command value Trq * is zero, the fundamental wave amplitude of the output voltage of the inverter INV exceeds “½” of the power supply voltage VDC (the modulation factor exceeds 1), so that d Weak field control is performed with the current command value id * of the shaft being negative.

  The d-axis current feedback control unit 26 calculates the d-axis command voltage vd * as an operation amount for performing feedback control of the d-axis current id to the current command value id *. Here, the command voltage vd * is the sum of the outputs of the proportional element and the integral element having the difference between the current command value id * and the current id as an input. Further, the q-axis current feedback control unit 28 calculates a q-axis command voltage vq * as an operation amount for feedback-controlling the q-axis current iq to the current command value iq *. Here, the command voltage vq * is the sum of the outputs of the proportional element and the integral element having the difference between the current command value iq * and the current iq as input.

  The three-phase conversion unit 30 converts the command voltages vd * and vq * into three-phase command voltages vu *, vv * and vw *.

  The operation signal generator 32 generates and outputs an operation signal g ¥ # so that the output voltage of the inverter INV is a simulation of the command voltages vu *, vv *, and vw *. Specifically, first, based on the magnitude comparison between the duty signal D ¥ obtained by normalizing the command voltage v ¥ * (¥ = u, v, w) with the power supply voltage VDC and the triangular carrier signal SC, the PWM signal g ¥ is calculated. Generate. Subsequently, the upper arm operation signal g ¥ p is generated by delaying the rising edge of the PWM signal g ¥ by the dead time. Further, the lower arm operation signal g \ n is generated by delaying the rising edge of the logical inversion signal of the PWM signal g \ by the dead time.

  Next, a control method when the torque command value Trq * is zero will be described. In the present embodiment, in the above-described processing, the switching on mode realized by setting the torque command value Trq * to zero and all of the switching elements Sup, Sun, Svp, Svn, Swp, Swn constituting the inverter INV are performed. Switching control is performed between the switching-off mode to be turned off. This is to achieve both reduction in loss and controllability of torque.

  That is, when the switching-on mode is adopted, the current flowing through the motor generator 10 causes the torque to be zero, but in reality, the currents id and iq are slightly smaller than the current command values id * and iq *. Fluctuates. For this reason, even if the current command values id * and iq * are zero, the current id and iq can take a value other than zero. On the other hand, the switching loss in the switching element S ¥ # is an integral value over the switching period of the switching state of the product of the current flowing through the switching element S ¥ # and the voltage at both ends of the switching element S ¥ #. The voltage across the element S ¥ # increases as the power supply voltage VDC increases. Therefore, when the terminal voltage (power supply voltage VDC) is large as in the storage means (high voltage battery 10) of the electrical energy supplied to the in-vehicle main machine (motor generator 10), the magnitude of the current flowing through the switching element S ¥ # Even if it is small enough to be ignored, if it does not steadily become zero, switching loss may not be negligible.

  On the other hand, no switching loss occurs in the switching off mode. However, when the induced voltage increases as the electrical angular velocity ω of the motor generator 10 increases, current can flow from the motor generator 10 to the high voltage battery 12 via the diode D ¥ #. In this case, since a current for charging the high voltage battery 12 flows, load torque is generated in the motor generator 10 in view of the energy conservation law.

  FIG. 2 shows a processing procedure for the switching control. This process is repeatedly executed by the control device 20 at a predetermined cycle, for example.

  In this series of processing, first, in step S10, it is determined whether or not the torque command value Trq * is zero. If it is determined to be zero, it is determined in step S12 whether or not the switching-off mode is set. If it is in the switching-off mode, it is determined in step S14 whether or not a condition that the q-axis current iq is smaller than the threshold current Iqth is satisfied. This condition is a condition for switching to the switching-on mode. This is set in view of the fact that when load torque is generated in the motor generator 10, the q-axis current becomes negative. The threshold current Iqth is set to zero in this embodiment. If a positive determination is made in step S14, the process proceeds to step S16 to switch to the switching on mode. In addition, the process of step S14, S16 comprises a switching means in this embodiment.

  On the other hand, if a negative determination is made in step S12, the induced voltage Viev is calculated in step S18. Here, the induced voltage Viev is calculated by multiplying the counter electromotive voltage constant φ by the electrical angular velocity ω. In the subsequent step S20, it is determined whether or not the d-axis current is zero or more and the induced voltage Viev is not more than the threshold voltage Vth. This condition is a condition for switching to the switching-off mode.

  Here, the condition that the d-axis current id is zero or more is that the torque is controlled to the torque command value Trq * while the amplitude value of the output voltage of each phase of the inverter INV is ½ or less of the power supply voltage VDC. It is a condition that it can be done. In this case, even if all the switching elements S ¥ # are turned off, it is considered that no current flows through the diode D ¥ #. On the other hand, the condition that the induced voltage Viev is equal to or lower than the threshold voltage Vth is for determining whether or not the induced voltage is small enough to prevent current from flowing through the diode D ¥ # in the switching-off mode. These two conditions are both conditions in which no current flows through the diode D ¥ # in the switching-off mode. However, in the present embodiment, the condition that the induced voltage Viev is equal to or lower than the threshold voltage Vth plays a role of securing a margin. This is based on the fact that the condition that the d-axis current id is zero or more holds even if the induced voltage is the maximum value in which no current flows through the diode D ¥ # in the switching-off mode. It is.

  When an affirmative determination is made in step S20, the process proceeds to the switching-off mode in step S22. In addition, the process of step S20, S22 comprises a switching means in this embodiment.

  Incidentally, when the processes in steps S16 and S22 are completed, or when a negative determination is made in steps S10, S14, and S20, the series of processes is temporarily terminated.

  Hereinafter, some of the effects of this embodiment will be described.

  (1) By performing switching processing between the switching-on mode and the switching-off mode, it is possible to achieve both a reduction in loss and maintenance of torque controllability in a situation where the torque command value Trq * is zero. it can.

(2) In the switching-off mode, when the magnitude of the current in the direction orthogonal to the field (q-axis current id) is equal to or greater than a specified value, the switching-on mode is switched. Thereby, such a situation can be solved in a situation where load torque is generated by setting the switching-off mode.
<Second Embodiment>
Hereinafter, the second embodiment will be described with reference to the drawings with a focus on differences from the first embodiment.

  FIG. 3 shows a system configuration according to the present embodiment. In FIG. 3, the same reference numerals are assigned for convenience to the members and processes corresponding to those shown in FIG.

  In the present embodiment, the third-order harmonic superimposing unit 31 superimposes the third harmonic on the command voltage v ¥ * obtained by three-phase conversion of the command voltages vd * and vq * on the dq axis, and this is applied to the power supply voltage VDC. Based on the magnitude comparison between the standardized duty signal D ¥ and the carrier signal SC, the operation signal g ¥ # is generated. Here, the superposition of the third harmonic is for expanding the region where the output line voltage of the inverter INV can simulate the fundamental wave to a region where the modulation factor is 1.15 or less. Here, the fact that the output line voltage of the inverter INV can simulate the fundamental wave means that the average value of the output line voltage of the inverter INV in one cycle of ON / OFF of the switching element S ¥ # is plotted for each cycle. This means that the trajectory can be a fundamental wave (a sine wave having an electrical angle period).

  FIG. 4 shows a processing procedure for switching control according to the present embodiment. This process is repeatedly executed by the control device 20 at a predetermined cycle, for example. In FIG. 4, the same step numbers are assigned for convenience to those corresponding to the processing shown in FIG.

  In this series of processes, if a negative determination is made in step S12, the modulation factor M is calculated in step S18a. In step S20a, it is determined whether the modulation factor M is equal to or less than the threshold value Mth. This process is for determining whether or not to switch to the switching-off mode. Here, threshold Mth is set in view of the fact that no current flows through diode D ¥ # due to the induced voltage of motor generator 10 in the switching-off mode when modulation factor M is 1 or less. Incidentally, whether or not to perform the process of superimposing the third harmonic in the switching on mode does not affect the setting of the threshold value Mth. If a positive determination is made in step S20a, the process proceeds to step S22.

  According to this embodiment described above, in addition to the effect (1) of the first embodiment, the following effect can be obtained.

(3) In the switching-on mode, when the modulation factor M is equal to or less than the threshold value Mth, the switching-off mode is switched. The modulation factor M is based on the command voltages vd * and vq * reflecting the influence of individual differences in the induced voltage of the motor generator 10 and changes in temperature. Therefore, when the switching off mode is set, the diode D ¥ # Whether or not current flows can be determined with high accuracy.
<Third Embodiment>
Hereinafter, the third embodiment will be described with reference to the drawings with a focus on differences from the first embodiment.

  FIG. 5 shows a processing procedure for switching control according to the present embodiment. This process is repeatedly executed by the control device 20 at a predetermined cycle, for example. In FIG. 5, the same step numbers are assigned for convenience to those corresponding to the processing shown in FIG. 2.

  In this series of processes, when an affirmative determination is made in step S10, the process proceeds to step S30. In step S30, the induced voltage Viev of the motor generator 10 is estimated. Here, the induced voltage Viev is calculated using a two-dimensional map that defines the relationship between the electrical angular velocity ω and the temperature Tr of the rotor of the motor generator 10 and the induced voltage Viev. Here, the reason why the rotor temperature Tr is used is that the amount of magnetic flux of the permanent magnet depends on the temperature. In addition, the process of step S30 comprises an induced voltage estimation means in this embodiment.

In a succeeding step S32, it is determined whether or not the induced voltage Viev is equal to or higher than the threshold voltage Vth. If an affirmative determination is made in step S32, the switching on mode is adopted in step S34, while if a negative determination is made, the switching off mode is adopted in step S36.
<Other embodiments>
Each of the above embodiments may be modified as follows.

About switching means
a) Switching process to switching-on mode In the first embodiment (FIG. 2), switching to the switching-on mode may be performed on condition that the d-axis current id is zero or more.

b) Switching processing to switching off mode As what switches to switching off mode based on the magnitude | size of the electric current which flows through the motor generator 10, in said 1st Embodiment (FIG. 2) and 2nd Embodiment (FIG. 4). It is not restricted to what was illustrated. For example, the condition may be that the magnitude of the current flowing through one or more terminals of the motor generator 10 is equal to or greater than a specified value, such as the current iv flowing through the V phase.

  Moreover, it is not restricted to the thing based on the magnitude | size of an electric current or the induced voltage Viev. For example, switching to the switching-on mode may be performed when the electrical angular velocity ω is equal to or higher than a threshold velocity. The threshold speed here may be set to a speed at which a load torque is generated in the motor generator 10 due to an increase in the induced voltage.

"Estimated voltage estimation means"
The temperature of the permanent magnet is not limited to the rotor temperature Tr, and for example, a detected value of the stator temperature may be substituted. Further, for example, an estimation unit that estimates the temperature of the permanent magnet based on the torque of the motor generator 10, the electrical angular velocity, the ambient temperature, and the like may be provided, and the estimated value may be used.

“Conditions for torque command value Trq * for switching control”
It is not limited to zero. For example, in order to control the actual torque of motor generator 10 to zero, when control is performed with torque command value Trq * added to a torque correction amount that compensates for mechanical loss, the motor generator 10 The torque command value Trq * when the current flowing through becomes zero is considered to be a small negative value. In this case, the switching control may be performed when the negative value is reached.

"On-mode control means"
The fact that the torque command value Trq * is not limited to zero is as described in the column “Regarding the conditions of the torque command value Trq * for performing switching control”.

  The d-axis current feedback control unit 26 and the q-axis current feedback control unit 28 are not limited to using the sum of the outputs of the proportional element and the integral element as the manipulated variable. For example, the output of the proportional element, the integral element, and the differential element The sum of them may be used as the operation amount.

  It is not limited to current feedback control means. For example, torque feedback control means for performing feedback control of an estimated torque estimated using the current of motor generator 10 as an input to torque command value Trq * may be used. For example, the fundamental wave amplitude of the output line voltage of the inverter INV as an open loop operation amount of the torque is set from the torque command value Trq * and the electrical angular velocity ω, and the operation amount of the torque feedback control is set as the output of the inverter INV. This can be realized by setting the voltage phase.

  The field weakening control means is not limited to the one provided with the current command value setting unit 24. For example, a means for calculating a command voltage vq * as an operation amount for performing feedback control of the q-axis current iq to a current command value iq * set according to the torque command value Trq *, a command voltage vq * and a power source Means may be provided for receiving a voltage VDC and calculating a command voltage vd * for setting the modulation factor to a specified value.

"About rotating machines"
For example, a surface magnet synchronous machine (SPMSM) or the like may be used instead of the IPMSM. Moreover, it is not restricted to a thing provided with a permanent magnet. For example, even if the electromagnet provided in the rotor and the energizing means for energizing the electromagnet through the insulating transformer are provided and the torque command value Trq * is zero, the electromagnet is continuously energized. Good.

  DESCRIPTION OF SYMBOLS 10 ... Motor generator (one Embodiment of a rotary machine), 20 ... Control apparatus, INV ... Inverter (One Embodiment of DC-AC conversion circuit).

Claims (7)

In order to control the control amount of the rotating machine (10), a switching element (S ¥ #) for selectively connecting the terminal of the rotating machine to each of the positive electrode and the negative electrode of the DC voltage source (12) and the switching element An operating means (20) for operating a DC / AC converter circuit (INV) including diodes (D ¥ #) connected in parallel;
The operation means includes
An on-mode control means for turning on / off the switching element of the DC / AC converter circuit so that the output voltage of the DC / AC converter circuit is such that the torque of the rotating machine is a specified value or less;
Off-mode control means for steadily turning off the switching element of the DC-AC converter circuit;
Switching means for performing a switching process of adopting the control of the on-mode control means or the control of the off-mode control means in order to control the torque of the rotating machine to be equal to or less than the specified value;
Equipped with a,
The on-mode control means is for operating the output voltage of the DC / AC converter circuit as a feedback operation amount for making the torque of the rotating machine equal to or less than the specified value.
Said switching means when the modulation index of the output voltage of the DC-AC converter according to the control of the on-mode control means is equal to or less than the threshold, the control of the rotating machine, wherein switching Rukoto the control of the off-mode control means apparatus.   2. The control of a rotating machine according to claim 1, wherein the switching unit performs the switching process according to whether or not a current flowing through the rotating machine exceeds a predetermined value by the control of the off-mode control unit. apparatus. 2. The switching means switches to the control by the on-mode control means on condition that the magnitude of the current flowing through the rotating machine becomes a specified value or more by the control by the off-mode control means. Or the control apparatus of the rotary machine of 2 . The switching means, on the condition that the magnitude of the component in the direction orthogonal to the field of the rotating machine out of the current flowing through the rotating machine by the control by the off-mode control means is not less than a specified value. 4. The rotating machine control device according to claim 3, wherein the control is switched to control by a control means. The switching means is
An induced voltage estimating means for estimating an induced voltage of the rotating machine,
Wherein depending on the size of the estimated induced voltage, the control device for a rotary machine according to claim 1 or 2, wherein the performing the switching process. 6. The control device for a rotating machine according to claim 5, wherein the induced voltage estimating means estimates the induced voltage by using a rotational speed of the rotating machine as an input. The rotating machine includes a permanent magnet,
7. The control device for a rotating machine according to claim 6, wherein the induced voltage estimation means takes into account the temperature of the permanent magnet in estimating the induced voltage.

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