JP2009106069A - Motor controller - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To prevent the deterioration of motor efficiency, by reducing a torque ripple inducing a mechanical resonance in a system to be driven, and to decrease the resources required for a motor controller. <P>SOLUTION: A target torque Tref*, which adds a ripple suppression value Tsup to a torque command value Tref, is generated so as to offset the torque ripples in resonance-speed regions 0 to N0 rpm, and the torque command value is used as the target torque, in regions other than the resonance-speed regions. The target torque adding the ripple suppression value to the torque command value is generated so as to offset the torque ripples, when there is motor operation in low-torque regions -T0 to +T0 Nm, or the resonance-speed regions capable of maintaining speed regions having a possibility of resonance continuation; and the torque command value is used as the target torque in regions, other than the resonance-torque and resonance-speed regions. A linear function representing the amplitude value Th of the low torque regions by an approximate straight line is used in a ripple-amplitude operation expression, and a linear function, representing a phase value α in the low-torque regions by the approximate straight line, is used in a ripple-phase operation expression. Alternatively, a quadratic or higher polynomial is used in both the operation expressions. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to an electric motor control device that supplies electric power to an electric motor from an inverter, and more particularly to electric motor control that suppresses torque ripple that causes mechanical resonance. Although the electric motor control device of the present invention is not intended to be limited to this, for example, the electric motor control device can be used for an electric vehicle in which wheels are driven by an electric motor.

JP 11-299277 A JP 2007-267465 A.

  In Patent Document 1, torque ripple data on a memory provided in a motor is read and stored in a memory of a driving device, torque ripple data corresponding to the output torque and rotation angle of the motor is read, and the read torque ripple data is offset. A motor drive device for correcting a torque command is described. Patent Document 2 proposes a motor control device that suppresses torque ripple at a frequency (sixth harmonic) that is six times the frequency of the drive voltage that the inverter applies to the permanent magnet motor. In the third embodiment (FIG. 3), the torque ripple amplitude A6f and phase φ6f data are stored in the 6f component compensation table 5A, and the amplitude A6f and phase φ6f corresponding to the output torque or torque command are tabled by the compensation signal calculation 5c. The torque ripple suppression value Tcr of the rotation angle θ of the motor is calculated by reading from 5A.

  A conventional mode of reading torque ripple suppression values corresponding to motor torque and rotation angle from a memory (for example, Patent Document 1) and a mode of reading torque ripple parameters corresponding to motor torque from a memory to calculate a torque ripple suppression value corresponding to a rotation angle (for example, In any of Patent Documents 2), a torque ripple suppression value is added to the command torque (addition is indicated when the suppression value is +, and subtraction is indicated when-), and the target torque is set by the motor control circuit. The inverter is controlled so that the output torque matches the target torque. Vector control is often used for this motor control.

  However, the torque ripple suppression value increases power loss and shortens the distance traveled by one battery charge. Torque ripple is a mechanical problem in a specific region of motor operation where the driven system resonates with torque ripple. For example, in wheel drive, this is a motor operating area when the passenger feels uncomfortable or the resonance sound becomes audible noise. According to the inventor's confirmation test, an unpleasant resonance may occur in a specific region of the motor rotation speed and a specific region of the motor output torque. However, the resonance does not occur outside the specific region. Therefore, torque ripple suppression outside the region where mechanical resonance occurs is not only unnecessary, but excess current flows and motor efficiency decreases. In addition, the resource of the motor control device for deriving or calculating the torque ripple suppression value, that is, the memory capacity or the calculation function, the memory retention or calculation of the torque ripple suppression value in the region outside the operation region where the torque ripple causes mechanical resonance. As a result, the cost becomes high.

  The first object of the present invention is to effectively reduce torque ripple that causes mechanical resonance in the driven system and to prevent a reduction in motor efficiency, and in addition, to reduce the required resources of the motor control device. The purpose.

  In order to achieve the first object, in the present invention, in the resonance speed region (0 to N0) where the torque ripple causes mechanical resonance, the ripple suppression value is set to the torque command value (Tref) so as to cancel the torque ripple. The added target torque (Tref *) is generated, and the torque command value (Tref) is set as the target torque (Tref *) outside the resonance speed region. The electric motor control apparatus of the present invention for carrying out this is the following item (1). In a preferred embodiment of the present invention to achieve the second object, the motor operation is performed in a predetermined torque region (-T0 to + T0) in which the torque ripple maintains the mechanical resonance speed region in the driven system, or A target torque (Tref *) is generated by adding a ripple suppression value (Tsup) to a torque command value (Tref) so as to cancel the torque ripple when in the resonance speed region, and outside the predetermined torque region or at a resonance speed When outside the region, the torque command value (Tref) is set as the target torque (Tref *); the first polynomial expresses the amplitude value (Th) of the predetermined torque region (-T0 to + T0) as an approximate straight line The second polynomial is a linear function representing the phase value (α) of the predetermined torque region (−T0 to + T0) with an approximate straight line. The motor control device of the present invention that implements this is the one described in items (5) to (7) below.

(1) DC power supply (18, 19); inverter (20) for controlling the exchange of power between the DC power supply and the motor (10); and the target torque (Tref *) and rotational speed (ω The motor control means (21) for controlling the inverter so that the output torque of the motor becomes the target torque based on
Means for deriving a ripple suppression value (Tsup) corresponding to an amplitude value (Th) and a phase value (α) corresponding to the motor torque of the torque ripple of the motor, and a rotation angle (θ) of the motor (41 to 47, 52); and
In the resonance speed region (0 to N0) in which the torque ripple causes mechanical resonance in the driven system, the target torque (Tref *) obtained by adding the ripple suppression value to the torque command value (Tref) so as to cancel the torque ripple. ) And outside the resonance speed region (0 to N), target torque correction means (48 to 51) using the torque command value (Tref) as the target torque (Tref *);
An electric motor control device comprising:

  In addition, in order to make an understanding easy, the code | symbol of the response | compatibility of an Example shown in drawing or an equivalent element or a matter, or an equivalent element or matter was added as reference for reference. The same applies to the following.

  According to this, the ripple suppression value (Tsup) is added to the torque command value (Tref) only in the resonance speed region (0 to N0) where the torque ripple causes mechanical resonance. Then, the target torque is the torque command itself and there is no reduction in motor efficiency. Torque ripples that cause mechanical resonance are effectively reduced, and there is no unnecessary reduction in motor efficiency.

(2) The means for deriving the ripple suppression value is:
Amplitude value calculation means (45 to 47) for calculating the amplitude value (Th) based on a first polynomial that approximates the torque-corresponding amplitude value (Th) of the torque ripple of the electric motor;
The phase value (α) is calculated based on a second polynomial that approximates the torque-corresponding phase value (α) of the torque ripple of the motor, and the calculated phase at the electrical angle (θ) of the rotation of the motor Vibration value calculation means (41 to 44) for calculating a vibration value [sin (nθ−α)] of the torque ripple having a value (α);
Suppression value calculation means (52) for calculating a ripple suppression value (Tsup) having a factor of a product of the vibration value and the amplitude value;
An electric motor control device according to (1) above (FIG. 3 / FIG. 8).

(3) The means for deriving the ripple suppression value is
An amplitude table (62) on the memory means, comprising an amplitude value group calculated on the basis of a first polynomial that approximates an amplitude value (Th) corresponding to torque of the torque ripple of the electric motor;
A phase table (61) on the memory means, which is composed of a phase value group calculated based on a second polynomial that approximates the torque-corresponding phase value (α) of the torque ripple of the motor;
A phase value (α) and an amplitude value (Th) corresponding to the torque of the motor are read from the phase table and the amplitude table, and have a calculated phase value (α) at an electrical angle (θ) of rotation of the motor. Vibration value calculating means (42 to 44) for calculating a vibration value [sin (nθ−α)] of the torque ripple;
Suppression value calculation means (52) for calculating a ripple suppression value (Tsup) with the vibration value and the amplitude value as factors;
The electric motor control device according to (1) above (FIG. 7 / FIG. 10).

  (4) The means for deriving the ripple suppression value does not execute the calculation of the ripple suppression value (Tsup) when the motor operation is outside the resonance speed range (0 to 40 rpm); ) The motor control device according to any one of (S21, S22, S28: FIG. 8). According to this, the calculation of the useless ripple suppression value is not performed.

  (5) The target torque correction means (48 to 51) is configured so that the motor operation is performed in a predetermined torque region (-T0 to + T0) in which the torque ripple maintains a mechanical resonance speed region in the driven system and the resonance speed region. The target torque (Tref *) is generated by adding the ripple suppression value to the torque command value (Tref) so as to cancel the torque ripple when it is at (0 to N0), and outside the predetermined torque region and the resonance When outside the speed region, the torque command value (Tref) is set as the target torque (Tref *); the motor control device according to any one of (1) to (3) (FIGS. 3 and 7) ).

  (6) The first polynomial is a linear function representing the amplitude value (Th) of the predetermined torque region (−T0 to + T0) with an approximate line; the motor control device according to (5) above (FIG. 3 / Fig. 7).

  According to this, since the approximate straight line is a short range in the resonance torque region and is a linear function, the calculation process is simple. Therefore, the required resources of the motor control device can be reduced. Since the range of linear approximation is narrow, the amplitude value (Th) can be calculated with high accuracy.

  (7) The second polynomial is a linear function representing the phase value (α) of the predetermined torque region (−T0 to + T0) by an approximate line; the motor control device according to (5) above (FIG. 3 / Fig. 7).

  According to this, since the approximate straight line is a short range in the resonance torque region and is a linear function, the calculation process is simple. Therefore, the required resources of the motor control device can be reduced. Since the range of linear approximation is narrow, the phase value (α) can be calculated with high accuracy.

  (8) The first polynomial is a second or higher order polynomial that approximates the amplitude value (Th) corresponding to torque; the motor control device (S23: FIG. 8 / FIG. 10) described in (2) or (3) above. ).

  (9) The second polynomial is a second or higher order polynomial that approximates the torque-corresponding phase value (α) (S24: FIG. 8 / FIG. 10); the motor control described in (2) or (3) above Apparatus (S24: FIG. 8 / FIG. 10).

  (10) The electric motor control device according to (5), (6), or (7), wherein the predetermined torque region is a predetermined low torque region (-T0 to + T0).

  (11) The resonance speed region is a predetermined low speed region (0 to N0); the motor control device according to (1) or (4) above.

  (12) The torque ripple is a frequency of a sixth harmonic of an output frequency of the inverter with respect to the motor; the motor control device according to (1) above.

  Other objects and features of the present invention will become apparent from the following description of embodiments with reference to the drawings.

  FIG. 1 shows an outline of the first embodiment of the present invention. In this embodiment, the electric motor 10 that is the motor to be controlled is incorporated in one of the front wheels of an electric wheelchair that supports an easy chair with three wheels (two front wheels and one rear wheel), and the front wheels are driven to rotate. This is a wheel-in motor that is a permanent magnet type synchronous motor and has a rotor with a built-in permanent magnet. The stator has U-phase, V-phase, and W-phase three-phase coils 11 to 13. A similar motor is built into the other front wheel. However, the rear wheels are non-driven wheels, and the entire wheels are steered by the steering mechanism.

  A voltage type inverter 20 supplies electric power of the battery 18 on the vehicle to the electric motor 10. The rotor of the resolver 17 for detecting the magnetic pole position of the rotor is connected to the rotor of the electric motor 10. The resolver 17 generates an analog voltage (rotation angle signal) SGθ representing the rotation angle of the rotor and supplies it to the motor control device 21.

  A battery 18 that is a storage battery on the vehicle is connected to a primary side capacitor in the converter 19 when the power supply unit on the vehicle is turned on, and constitutes a primary side DC power source together with the battery 18. A primary voltage sensor in converter 19 provides voltage detection signal Vdc representing the voltage of the primary side capacitor (voltage of on-vehicle battery 18) to motor control device 21. In this embodiment, a voltage dividing resistor is used for the voltage sensor. In the converter 19, one end of the reactor is connected to the positive electrode (+ line) on the primary side.

  The converter 19 further includes a step-up switching element for turning on and off between the other end of the reactor and the negative electrode (−line) on the primary side, the positive electrode of the secondary capacitor in the converter 19, and the other end of the reactor. There are regenerative switching elements that are turned on and off, and diodes connected in antiparallel to each switching element. When the step-up switching element is turned on (conductive), a current flows from the primary side to the step-up switching element via the reactor, whereby the reactor accumulates, and when the step-up switching element is turned off (non-conducting), the reactor Discharges to the secondary capacitor through a diode for boosting current. That is, a voltage higher than the voltage of the primary side DC power supply is induced to charge the secondary side capacitor. By repeatedly turning on and off the step-up switching element, high-voltage charging of the secondary side capacitor is continued. That is, the secondary capacitor is charged with a high voltage. If this ON / OFF is repeated at a constant cycle, the power stored in the reactor increases according to the length of the ON period, so the ON time (ON duty: ON time ratio with respect to the fixed cycle) during the fixed cycle is By adjusting, that is, by PWM control, the speed at which power is supplied from the primary power supply 18 to the secondary capacitor via the converter 19 (powering speed for powering) can be adjusted. When the regenerative switching element is turned on, the accumulated power of the secondary side capacitor is supplied to the primary side power supply 18 through the regenerative switching element and the reactor (reverse feeding: regenerative). Also in this case, the speed at which power is reversely fed from the secondary capacitor to the primary power source 18 by adjusting the ON time of the regenerative switching element during a certain period, that is, by PWM control (power feed speed for regeneration). Can be adjusted.

  Voltage type inverter 20 includes a drive circuit and six switching transistors, and each transistor is turned on (conducted) by each series of six series of drive signals generated in parallel by the drive circuit. The DC voltage of the secondary capacitor (converter output voltage or secondary voltage) is converted into a triple AC voltage having a phase difference of 2π / 3, that is, a three-phase AC voltage. , V-phase, W-phase) stator coils 11-13. As a result, the respective phase currents iU, iV, iW flow through the stator coils 11 to 13 of the electric motor 10, and the rotor of the electric motor 10 rotates. In order to increase the power supply capability for the on / off drive (switching) of the six transistors by the PWM pulse and suppress the voltage surge, the secondary output line of the converter 19, which is the input line of the inverter 20, A large-capacity secondary capacitor (in the converter 19) is connected. On the other hand, the primary side capacitor in the converter 19 has a small size and low cost, and the capacity of the primary side capacitor is considerably smaller than that of the secondary side capacitor. A secondary voltage sensor in the converter 19 detects the secondary voltage Vuc of the converter 19 and supplies it to the motor control device 21. Current sensors 14 to 16 using Hall ICs are attached to the power supply lines connected to the stator coils 11 to 13 of the electric motor 10. The current sensors 14 to 16 detect the phase currents iU, iV, and iW, respectively. Analog voltage) is generated and applied to the motor controller 21.

  FIG. 2 shows a functional configuration of the motor control device 21. In this embodiment, the motor control device 21 is an electronic control device mainly composed of a microcomputer (hereinafter referred to as a microcomputer) MPU, and the microcomputer MPU, a drive circuit in the inverter 20, each phase current sensor, the resolver 17, and a converter. 19 includes an interface (signal processing circuit) (not shown) between the primary voltage sensor and the secondary voltage sensor in 19, and further between the microcomputer and a main controller of the vehicle travel control system (not shown) on the vehicle. Also, an interface (communication circuit) not shown is included.

  Referring to FIG. 2, based on the rotation angle signal SG θ given by the resolver 17, the microcomputer MPU in the motor control device 21 calculates the rotation angle (electric angle) θ and the rotation speed (angular velocity) ω of the rotor of the electric motor 10. calculate. To be precise, the rotation angle and the electrical angle of the rotor of the electric motor 10 are not the same, but they are in a proportional relationship, and the proportionality coefficient is determined by the number of magnetic poles p of the electric motor 10. Further, although the rotational speed and the angular speed are not the same, both are in a proportional relationship, and the proportionality coefficient is determined by the number of magnetic poles p of the electric motor 10. In this document, the rotation angle θ means an electrical angle. The rotational speed ω means an angular speed, but sometimes means a rotational speed (rpm).

  A main controller of the vehicle travel control system (not shown) gives a motor command torque TM * to the microcomputer of the motor control device 21. The main controller calculates a vehicle request torque TO * based on the vehicle speed and the accelerator opening of the vehicle, generates a motor command torque TM * corresponding to the vehicle request torque TO *, and sends it to the microcomputer MPU. give. The microcomputer MPU outputs the rotation speed ω rpm of the electric motor 10 to the main controller.

  The microcomputer MPU of the motor control device 21 reads the limit torque TM * max corresponding to the secondary voltage Vuc and the rotational speed ω from the limit torque table (lookup table) by the torque command limit 24, and the command torque TM * is TM. If * max is exceeded, TM * max is determined as the command torque T *. When it is equal to or less than TM * max, the motor command torque TM * is set to the command torque Tref. The command torque Tref generated by adding such a restriction is given to the torque ripple suppression value calculation 25 and the secondary target voltage calculation 31.

  The limit torque table is a memory area in which each value of the secondary voltage Vuc and the rotation speed is used as an address, and the maximum torque that can be generated in the electric motor 10 with each value is written as the limit torque TM * max. In this embodiment, it means one memory area of a RAM (not shown) in the microcomputer MPU. The limit torque TM * max is larger as the secondary voltage Vuc is higher, and is smaller as the secondary voltage Vuc is lower. Further, the lower the rotation speed ω, the larger the value, and the smaller the rotation speed ω.

  In the microcomputer, there is a non-volatile memory in which the limit torque table data TM * max is written, and the microcomputer initializes itself and the motor drive system shown in FIG. 1 when an operating voltage is applied to the microcomputer. Then, the data is read from the nonvolatile memory and written to the RAM. There are a plurality of other similar look-up tables in the microcomputer, which will be described later. These, like the limit torque table, also mean a memory area on the RAM in which the reference data in the nonvolatile memory is written.

  The torque ripple suppression value calculation 25 calculates a torque ripple suppression value Tsup corresponding to the torque command Tref, the rotation angle θ, and the rotation speed ω. A value obtained by subtracting the torque ripple suppression value Tsup from the torque command Tref, that is, a value obtained by adding a correction for the torque ripple suppression value Tsup to the torque command Tref is given to the output calculation 27 via the subtraction 26 as the target torque Tref *. The contents of the torque ripple suppression value calculation 25 will be described later with reference to FIG.

  In the secondary target voltage calculation 31, the microcomputer MPU of the motor control device 21 determines “powering” or “regeneration” based on the torque command Tref and the rotational speed ω, and if it is “powering”, the “powering” group The secondary target voltage Vuc * assigned to the rotational speed ω of the electric motor 10m is read from the secondary target voltage table assigned to the torque command Tref in the “regeneration” group.

  Based on the secondary target voltage Vuc * and the current secondary voltage Vuc, the microcomputer MPU generates a PWM pulse as a control output PVC for setting the secondary voltage Vuc to the secondary target voltage Vuc * by feedback control calculation 23. Is supplied to the vessel 34. The pulse generator 34 converts the control signal Pvc into a PWM pulse Pvf that drives the boosting (powering) switching element of the converter 19 to be turned on and off during power running, and the regeneration switching element is turned off. The signal is output to the drive circuit in the converter 19 together with the signal Pvr to be restrained. At the time of regeneration, the switching element for regeneration of the converter 19 is converted to a PWM pulse Pvr for driving on and off, and the boosting (powering) switching element is output to the drive circuit together with the signal Pvf constrained to be turned off. The drive circuit turns on, off, or turns off the switching element based on the signals Pvf and Pvr. Thereby, the secondary voltage Vuc becomes the target value Vuc *.

  In the “output calculation” 27, the microcomputer of the motor control device 21 uses a d-axis in the direction of the magnetic pole pair in the rotor of the electric motor 10 and a q-axis in the direction perpendicular to the d-axis, respectively. Performs feedback control by vector control calculation on the axis model. Therefore, the microcomputer digitally converts and reads each phase current detection signal iU, iV, iW, and uses a three-phase / two-phase conversion, which is a known fixed / rotating coordinate conversion, in a current feedback calculation to obtain a fixed coordinate. The three-phase current values iU, iV, and iW are converted into the d-phase and q-axis two-phase current values id and iq on the rotation coordinates.

  The first high-efficiency torque curve table A, which is one look-up table, is included in the output calculation 27, and each motor speed associated with the motor speed ω and the torque command Tref is included in the first high-efficiency torque curve table A. Each d-axis current value id for generating each torque command Tref is written.

  The output torque of the electric motor is determined corresponding to each value of the d-axis current id and the q-axis current iq, but id for outputting the same torque for one rotation speed value, that is, at the same motor rotation speed. , Iq are innumerable and are on a constant torque curve. On the constant torque curve, there is a combination of id and iq with the highest power usage efficiency (lowest power consumption), which is the high efficiency torque point. A curve connecting high efficiency torque points on a plurality of torque curves is a high efficiency torque curve and exists for each rotation speed. By energizing the electric motor 10 with the d-axis current id and the q-axis current iq at the position of the given motor command torque Tref on the high-efficiency torque curve addressed to the rotation speed of the motor as target current values, The electric motor 10 outputs Tref, and the power usage efficiency of the motor energization is high.

  In this embodiment, the high-efficiency torque curve is divided into two systems: a first high-efficiency torque curve A that represents the d-axis value and a second high-efficiency torque curve B that represents the q-axis value. The high-efficiency torque curve A is a pair of the one applied to the power running region and the one applied to the regeneration region, and both represent the d-axis target current with respect to the motor rotation speed and the target torque.

  The first high-efficiency torque curve table A is a memory area in which a d-axis target current for generating a target torque with minimum power consumption, which is addressed to the command torque Tref, is written, and a power running table A1 for power running, It consists of a pair of regeneration tables A2 for regeneration. Whether to use the table for power running or regeneration is determined according to the determination result by determining whether the table is power running or regeneration based on the rotational speed ω of the electric motor and the given torque command Tref.

  However, as the rotational speed ω of the electric motor 10 increases, the counter electromotive force generated in the stator coils 11 to 13 increases, and the terminal voltages of the coils 11 to 13 increase. Accordingly, it becomes difficult to supply the target current from the inverter 20 to the coils 11 to 13, and a target torque output cannot be obtained. In this case, on the constant torque curve of the given torque command Tref, by reducing Δid, Δiq, d-axis current id and q-axis current iq along the curve, the power usage efficiency is reduced, but the torque command Tref Can be output. This is called field weakening control. The d-axis field weakening current Δid is generated by field adjustment allowance calculation, calculates a d-axis current command, and calculates a q-axis current command. The d-axis field weakening current Δid is calculated by the field weakening current calculation 28. The contents will be described later.

  The microcomputer MPU calculates the d-axis current command in the “output calculation” 27 from the d-axis current value id read from the first high efficiency torque curve table A corresponding to the command torque Trefm determined by the torque command limitation. The d-axis field weakening current Δid is subtracted to calculate the d-axis target current id * as id * = − id−Δid.

  In the calculation of the q-axis current command, the second high efficiency torque curve table B in the output calculation 27 is used. The second high-efficiency torque curve table B further includes a second high-efficiency torque curve B representing the q-axis value of the high-efficiency torque curve, and a d-axis field weakening current Δid and a pair of q-axis field weakening current Δiq. The data is corrected to a curve representing the subtracted q-axis target current, and the data of the corrected second high efficiency torque curve B is stored. The second high-efficiency torque curve table B is a d-axis target current for generating a target torque with minimum power consumption, which is addressed to the torque command Tref and the d-axis field weakening current Δid, that is, a corrected second high This is a memory area in which the target current value of the efficiency torque curve B is written, and this is also composed of a pair of a power running table B1 for power running and a regeneration table B2 for regeneration. Whether to use powering or regenerative power is determined based on the determination result by determining whether it is powering or regenerating based on the rotational speed ω of the electric motor and the command torque Trefm.

  In calculating the q-axis current command, the q-axis target current iq * addressed to the command torque Tref and the d-axis field weakening current Δid is read from the second high-efficiency torque curve table B and used as the q-axis current command.

  In the output calculation 27, the microcomputer of the motor control device 21 calculates a current deviation δid between the d-axis target current id * and the d-axis current id and a current deviation δiq between the q-axis target current iq * and the q-axis current iq. Then, proportional control and integral control (PI calculation of feedback control) are performed based on the current deviations δid and δiq to calculate the d-axis voltage command value vd * and the q-axis voltage command value vq * as output voltages.

  Next, in the two-phase / three-phase conversion 29 that is the rotation / fixed coordinate conversion, the target voltages vd * and vq * on the rotation coordinates are changed to the phase target voltages VU * on the fixed coordinates according to the two-phase / three-phase conversion. , VV *, VW *. This is sent to the PWM pulse generator 33 via the modulation 30 when the voltage control mode is three-phase modulation. When the voltage control mode is a three-phase modulation, the PWM pulse generator converts the phase target voltages VU *, VV * and VW * of the three-phase modulation mode into those of the two-phase modulation by the two-phase modulation 38 of the modulation 30. Send to 33. When the voltage mode is a 1 pulse mode in which all phases are energized with rectangular waves, each phase target voltage VU *, VV *, VW * in the 3-phase modulation mode is energized with each phase rectangular wave by 1 pulse conversion of modulation 30. The signal is converted into a signal and supplied to the PWM pulse generator 33.

  The PWM pulse generator 33, when given the three-phase target voltages VU *, VV *, VW *, converts them into PWM pulses MU, MV, MW for outputting the respective voltage values, and a voltage type inverter 20 is output to the drive circuit in 20. The drive circuit generates six series of drive signals in parallel based on the PWM pulses MU, MV, and MW, and turns on / off each of the six transistors of the inverter 20 with each series of drive signals. Thereby, VU *, VV * and VW * are applied to each of the stator coils 11 to 13 of the electric motor 10, and the phase currents iU, iV and IW flow. When each phase target voltage in the two-phase modulation mode is given, the PWM pulse generator generates a PWM pulse for two phases and an on or off (constant voltage output) signal for the remaining one phase. When each phase target voltage in the 1 pulse modulation mode is given, an energization section signal for making each phase a rectangular wave energization is output.

  The field weakening current calculation 28 calculates a voltage saturation index that is a parameter for field weakening control. That is, based on the d-axis voltage command value vd * and the q-axis voltage command value vq *, the voltage saturation calculation value ΔV is calculated as a value representing the degree of voltage saturation, and the field adjustment allowance is calculated.

  In the calculation of the field adjustment allowance, when ΔV is integrated and the integrated value ΣΔV takes a positive value, the integrated value ΣΔV is multiplied by a proportional constant to calculate a d-axis field weakening current Δid for performing field weakening control. When the voltage saturation calculation value ΔV or the integrated value ΣΔV takes a value less than or equal to zero, the adjustment value Δid and the integrated value ΣΔV are set to zero. The adjustment value Δid is used in the calculation of the d-axis current command and the q-axis current command.

  “2-phase / 3-phase conversion” 29 calculates the motor target voltage Vm * in the process of 2-phase / 3-phase conversion. Vm * = √ (Vd * 2 + Vq * 2). From the motor target voltage Vm * and the secondary voltage Vuc of the converter 19, the modulation 30 calculates the modulation ratio Mi = Vm * / Vuc *. The modulation 30 determines a modulation mode based on the torque command Tref, the rotation speed ω, and the modulation ratio Mi of the electric motor 10, and outputs each phase target voltage of the modulation mode according to the determined modulation mode. The motor control by the combination of the functions shown in FIG. 2 and described above is so-called vector control.

  Here, the background to the adoption of the “torque ripple suppression value calculation” 25 of FIG. 2 will be described. Due to the vector control described above, the torque ripple shown in FIG. 11 is generated in the motor torque, and the wheel may resonate with this. Further, it has been found that the torque ripple may give an unpleasant feeling or anxiety to the occupant (driver) in a low torque range of 0 to 4 Nm at the time of slow start (slow start). The torque ripple shown in FIG. 11 corresponds to the frequency of the drive voltage applied to the motor coil, that is, the sixth harmonic of the drive frequency (fundamental wave), and the amplitude and phase change depending on the value of the motor torque. In FIG. 11, an elliptical circle is added to the phase zero point. The position of this elliptical circle (the point of ripple phase 0) being different for each motor torque means that the ripple phase changes depending on the value of the motor torque. FIG. 12 shows the phase α of the sixth harmonic torque ripple corresponding to the torque command Tref, and FIG. 13 shows the amplitude Th corresponding to the torque command Tref. Since a high-efficiency torque curve is used in the vector control described above, a combination (one point) that minimizes the motor administration power is selected from various combinations of the id value and iq value that generate torque of the torque command Tref. For each value of the torque command Tref, the field angle at the high-efficiency torque point changes for each output torque value, as shown by a thick curve rising to the right in FIG. It is assumed that this changes the phase α in response to the torque command Tref.

As shown in FIG. 13, the torque ripple is small in the low torque region and large in the high torque region, but the ratio of the amplitude of the torque ripple to the torque command Tref in the low torque region is much larger than a similar ratio in the high torque region. Therefore, the torque ripple is easily felt by the passenger in the low torque region. The low torque region is also a torque region that maintains a speed region in which the mechanical resonance caused by the torque ripple in the driven system continues.
Therefore, in this embodiment, in order to suppress the torque ripple of the sixth harmonic in the low torque region where the torque command Tref is −T0 to + T0 Nm or slightly wider than that, the ripple amplitude Th value corresponding to the torque command Tref (FIG. 13) is set. In the range of 0 to T1 Nm of the torque command Tref,
Th = k1 · Tref + k0,
k1, k0 constants,
Similarly, the ripple phase α value corresponding to the torque command Tref (FIG. 12) is set in the range of −T1 to + T1 Nm of the torque command Tref.
α = α1 · Tref,
α1: constant,
And a linear approximation. Since the error of the linear approximation increases outside the above range, this is suppressed, and in the region of the high torque command where torque ripple suppression is unnecessary, the ripple suppression amount is set to 0 in order to avoid motor efficiency reduction. A limiting ratio Rt corresponding to the torque command shown in FIG. 4A is added to the calculation factor of the torque ripple suppression amount Tsup. As a result, in the range of -T1 to + T1 Nm of the torque command Tref, the ripple suppression amount Tsup using Th and α as parameters.
Tsup = Th · sin (nθ−α),
n = 6,
Is calculated, but in the regions within −T1 Nm and within + T1 Nm outside −T0 to + T0 Nm of the torque command Tref, the approximate calculation value is gradually suppressed by Rt and finally becomes 0, and −T1 to + T1 Nm Outside of, the ripple suppression amount Tsup is zero.

  On the other hand, according to the motor control of the present embodiment, the motor 10 may resonate with the torque ripple in a low speed region of about N0 rpm or less, but the possibility of resonating at high speed rotation disappears. Therefore, in the present invention, the limiting ratio Rn corresponding to the rotational speed shown in FIG. 4B is added to the calculation factor of the torque ripple suppression amount Tsup. Thereby, the ripple suppression amount Tsup is calculated in the low speed region where the rotational speed is N0 rpm or less, but in the outer speed region within N1 rpm, the approximate calculation value Tsup is gradually suppressed by Rn and finally becomes zero. In the high speed region of N1 rpm or more, the ripple suppression amount Tsup is zero.

  FIG. 3 shows a functional configuration of “torque ripple suppression value calculation” 25 shown in FIG. Amplification (multiplication) 41 multiplies torque command Tref by α1, which is the gradient of the phase approximation line, and outputs a product, that is, torque ripple phase α. Amplification (multiplication) 42 is subject to suppression at rotation angle θ. Is multiplied by the order n of the torque ripple (n = 6 in this embodiment), and the product, that is, the phase angle nθ is output. The subtraction 43 calculates the instantaneous phase angle (nθ−α) of the torque ripple, and the sin function calculation 44 calculates the sin value sin (nθ−α) of the phase angle (nθ−α).

On the other hand, the amplification (multiplication) 45 multiplies the torque command Tref by k1 which is the gradient of the above-mentioned amplitude approximation line, and the addition 47 adds the constant k0 in the register 46 to output the torque ripple amplitude value Th. To do. The torque command corresponding limit ratio table 48, which is the torque command corresponding limit ratio Rt group shown in FIG. 4A, stored in the memory outputs the limit ratio Rt corresponding to the torque command Tref and stored in the same memory. The rotation speed corresponding limit ratio table 49, which is the rotation speed corresponding limit ratio Rn group shown in FIG. 4B, outputs the limit ratio Rn corresponding to the rotation speed ω of the motor, and the multiplication 50 is the both limit ratio Rt. , Rn, Rtn = Rt · Rn is calculated, Multiply 51 calculates Th · Rtn, Multiply 52 calculates the product of sin (nθ−α) and Th · Rtn, The ripple suppression value Tsup is output to the subtraction 26 in FIG.
Tsup = Rt.Rn.Th.sin (n.theta .-. Alpha.)
Therefore, Rt and Rn are factors of Tsup.

  In addition to the CPU, the microcomputer MPU shown in FIG. 2 includes RAM, ROM, and flash memory for recording data and various programs, and programs stored in the ROM or flash memory. , The reference data and the lookup table are written in the RAM, and input processing, calculation and output processing shown in FIG. 2 surrounded by a two-dot chain line block are performed based on the program.

  FIG. 5 shows an outline of the motor drive control MDC executed by the microcomputer MPU (or its CPU) based on the program. When the operating voltage is applied, the microcomputer MPU initializes itself, the PWM pulse generators 33 and 34, the inverter 20 and the converter 19, and sets the inverter 20 that drives the motor 10 to a stop standby state. Then, it waits for a motor drive start instruction from a main controller of a vehicle travel control system (not shown). When the motor drive start instruction is given, the microcomputer MPU sets the initial value of the motor control in the internal register by the “start process” (step S1), and the input signal or data by the “input read” (step S2). Is read. That is, the first command torque TM * provided by the main controller, the phase current values iU, iV, iW detected by the phase current sensors, and the rotation angle signal SGθ of the resolver 17 are read by digital conversion.

  In the following, the word “step” is omitted, and only the step number is written in parentheses.

  Next, the microcomputer MPU calculates the rotation angle θ and the rotation speed ω based on the read rotation angle signal SGθ (rotation angle data SGθ) (S3). This function is shown as an angle / speed calculation 23 in FIG. Next, the microcomputer MPU converts the read three-phase current detection signals iU, IV, iW into a two-phase d-axis current value id and a q-axis current value by three-phase / two-phase conversion (S4). This function is shown as current feedback 22 in FIG. Next, the microcomputer MPU calculates a d-axis field weakening current Δid for performing d-axis field weakening control (S5). This function is shown as field weakening current calculation 28 in FIG. Next, the microcomputer MPU reads the read motor command torque TM *, the secondary voltage Vuc and the limit torque TM * max corresponding to the calculated rotation speed ω from the limit torque table, and the read motor command torque TM * is TM *. If it exceeds max, TM * max is set in the torque command Tref. When it is equal to or less than TM * max, the read motor command torque TM * is determined as the torque command Tref (S6). This function is shown as a torque command limit 24 in FIG.

  Next, in the “secondary target voltage calculation” (S7), the microcomputer MPU determines whether the electric motor 10 is in “power running” operation or “regenerative” operation, selects a group corresponding to the determination result, The secondary target voltage Vuc * assigned to the current rotational speed ω is read from the secondary target voltage table associated with the command torque Tref. The content of the “secondary target voltage calculation” (S7) is the same as the content of the secondary target voltage calculation 31 shown in FIG. In the next “secondary voltage control calculation” (S 8), a control output Pvc for setting the secondary voltage Vuc of the converter 19 to the secondary target voltage Vuc * is generated and supplied to the PWM pulse generator 34. This content is the same as the content of the feedback control calculation 23 shown in FIG.

  In “torque ripple suppression” (S9), the target torque Tref * is calculated by calculating the ripple suppression value Tsup in the torque ripple suppression calculation 25 shown in FIG. 3 and the subtraction 26 shown in FIG. The contents of the “output calculation” (S10) are the same as the contents of the output calculation 27 shown in FIG. The dq-axis voltage target values Vd * and Vq * calculated in the “output calculation” (S10) are converted into the phase target voltages VU *, VV * and VW * in the three-phase modulation mode (S11). At this time, the motor target voltage Vm * is also calculated. In the next “modulation control” (S12), the modulation ratio Mi is calculated (S13), and the modulation mode is determined based on the modulation ratio Mi, the command torque Tref and the rotational speed ω (S14). Parameters referred to for determining the modulation mode include the torque command Tref, the rotational speed ω, and the modulation ratio Mi. The microcomputer MPU has a modulation threshold table (look-up table) associated with a modulation mode (three-phase modulation, two-phase modulation, 1 pulse) and a modulation ratio, and each modulation threshold table has a threshold (target) at the modulation mode boundary. Torque value and rotation speed value) are stored. In the “modulation area determination” (S14), the microcomputer MPU selects a modulation threshold table corresponding to the current modulation mode (three-phase modulation, two-phase modulation, or 1 pulse) and the modulation ratio, and then reads the threshold value to determine the torque. The command Tref and the rotation speed are compared with a threshold value to determine a modulation mode to be adopted next.

  In the next “output update” (S 15), each phase target voltage in the modulation mode determined in the modulation control (S 12) is output to the PWM pulse generator 33. Next, after waiting for the next repetitive processing timing (S16), the process proceeds to "input reading" (S2) again. Then, the above-described “input reading” (S2) and subsequent processes are executed. If there is a stop instruction from the system controller while waiting for the next repetitive processing timing, the microcomputer MPU stops the output for energizing the motor rotation (S17, S18).

  FIG. 6 shows the torque ripple reduction effect when the first embodiment (embodiment 1) is applied. According to the first embodiment, torque ripple is largely suppressed in the torque region of -T1 to + T1 Nm, particularly in the low torque region -T0 to + T0 Nm. Outside of -T1 to + T1 Nm, Rt = 0 ((a) of FIG. 4) has no ripple suppression effect, but since the torque command is large in this outside region, the wheel does not resonate with the torque ripple. In other words, the first embodiment suppresses torque ripple in the low torque region where there is a high possibility that wheel resonance will continue.

  In the first embodiment, the limiting ratio Rn corresponding to the rotational speed is a factor of the ripple suppression value Tsup, and Rn is 1 in the low speed region where the rotational speed is N0 rpm or less as shown in FIG. (100%), the speed region within N1 rpm on the outer side thereof becomes smaller in the order of less than 1 and finally becomes 0 at N1 rpm, and becomes 0 in the high speed region above N1 rpm. What is added to the torque command value Tref is only a resonance speed region (within about N0 rpm) in which the torque ripple causes mechanical resonance. Outside the resonance speed region, the target torque Tref * is the torque command Tref itself and there is no reduction in motor efficiency. That is, the torque ripple that causes mechanical resonance is effectively reduced, and there is no unnecessary reduction in motor efficiency.

  Further, the limit ratio Rt corresponding to the torque command is a factor of the ripple suppression value Tsup, and Rt is 1 (100%) when the torque command Tref is equal to or less than T0 Nm, as shown in FIG. In the torque region within T1 Nm, the value gradually decreases below 1 and finally becomes 0 at T1 Nm, and becomes 0 in the torque region above T1 Nm. Therefore, the effective ripple suppression value Tsup is changed to the torque command value Tref. What is added is only a low torque region (within about T0 Nm) that maintains a speed region in which the mechanical resonance brought about by the torque ripple in the driven system may continue. Outside the low torque region, the target torque Tref * is the torque command Tref itself and there is no reduction in motor efficiency. That is, mechanical vibration or resonance due to torque ripple is effectively reduced, and unnecessary motor efficiency reduction is eliminated.

  Since the above-described limiting ratios Rn and Rt are factors of the ripple suppression value Tsup, the motor operation is likely to cause the torque ripple to be felt by the driver, and the mechanical resonance caused by the torque ripple in the driven system may continue. An effective ripple suppression value is a torque command so as to cancel the torque ripple when maintaining a certain speed region, in a low torque region (-T0 to + T0 Nm), or in the resonance speed region (0 to N0 rpm). When the target torque Tref * added to the value is generated and is outside the low torque region and the resonance speed region, the torque command value Tref becomes the target torque Tref *.

  Furthermore, in the present embodiment, the first polynomial for calculating the torque ripple amplitude value Th is a linear function that represents the torque ripple amplitude value in the low torque region (FIG. 13) as an approximate straight line. Similarly, the torque ripple phase α is calculated. Since the second polynomial is a linear function that represents the torque ripple phase (FIG. 12) in the low torque region by an approximate line, that is, a linear approximation of a narrow range, the calculation process is simple. Therefore, the required resources of the motor control device can be reduced. Since the range of linear approximation is narrow, the amplitude value Th and the phase α can be calculated with high accuracy.

  The torque command Tref is given to the “torque ripple suppression value calculation” 25, but the output torque of the electric motor 10 or the estimated output torque value may be given instead of the torque command Tref. Moreover, although the electric motor 10 is a permanent magnet synchronous motor, the present invention can be similarly applied to a reluctance synchronous motor.

The hardware of the second embodiment is the same as that of the first embodiment described above, and the functions are the same. However, “torque ripple suppression value calculation” of the second embodiment is changed to “torque ripple suppression value calculation” 25a shown in FIG. The ripple phase table 61 of this “torque ripple suppression value calculation” 25a has the above approximate calculation formula of the ripple phase α α = α1 · Tref,
α1: constant,
The ripple phase value α corresponding to the torque command Tref in the region of −T1 to + T1 Nm calculated in step S1 and stored in the memory, and the ripple phase value α associated with the given torque command Tref is output. The ripple amplitude table 62 is an approximation formula for the ripple amplitude Th described above Th = k1 · Tref + k0,
k1, k0: constants,
The ripple amplitude value Th corresponding to the torque command Tref in the range of 0 to T1 Nm calculated in step S1 and stored in the memory is output, and the ripple amplitude value Th associated with the given torque command Tref is output. Other functions of the “torque ripple suppression value calculation” 25a are the same as the “torque ripple suppression value calculation” 25 of the first embodiment, and output the ripple suppression value Tsup substantially the same as that of the first embodiment. Other configurations and functions of the second embodiment are the same as those of the first embodiment.

  The hardware of the third embodiment is the same as that of the first embodiment, and the outline of the function is the same. However, the “torque ripple suppression” of the third embodiment is changed to “torque ripple suppression” S9a shown in FIG. 8 in which the ripple amplitude Th and the phase α are calculated in the entire region of the torque command Tref using a sixth-order ripple approximation function. The torque command corresponding limit ratio table 48 is omitted. “Torque ripple suppression” S9a of the third embodiment is replaced with “torque ripple suppression” (S9) shown in FIG. That is, the motor drive control MDC of the third embodiment is obtained by changing “torque ripple suppression” S9 in the motor drive control MDC of the first embodiment shown in FIG. 5 to “torque ripple suppression” S9a shown in FIG. .

  Please refer to FIG. When the process proceeds to "torque ripple suppression" S9a, the microcomputer MPU of the motor control device of the second embodiment reads the limit ratio Rn (FIG. 4B) corresponding to the torque command Tref from the rotation speed corresponding limit ratio table 49 (S21). . If the read Rn is 0 or less, the target torque Tref * is set as the torque command Tref (S22, S28).

If the read Rn is greater than 0, the sixth-order function Th = k6 · Tref6 + k5 · Tref5 + k4 · Tref4 + k3 · Tref3 + k2 · Tref2 + k1 · Tref1 + k0 approximating the ripple amplitude (reference example 1 in FIG. 6)
k6 to k0: A ripple amplitude value Th corresponding to the torque command Tref is calculated using a constant (S22, S23), and similarly, a sixth-order function α = α6 · Tref6 + α5 · Tref5 + α4 approximating the ripple phase (curve in FIG. 12)・ Tref4 + α3 ・ Tref3 + α2 ・ Tref2 + α1 ・ Tref1 + α0
α6 to α0: A ripple phase value α corresponding to the torque command Tref is calculated using a constant (S24). Using the calculated ripple phase value α, sin (nθ−α) is calculated (S25). n is the order of the torque ripple to be suppressed. In this embodiment, n = 6. Then, the ripple suppression value Tsup is calculated as follows (S26), and the target torque Tref * is calculated as follows (S27):
Tsup = Rn, Th, sin (nθ-α)
Tref * = Tref−Tsup
In the present embodiment, the ripple suppression value Tsup is calculated in the entire range of the torque command Tref, but the limiting ratio Rn corresponding to the rotational speed is a factor of the ripple suppression value Tsup, and Rn is as shown in FIG. In addition, 1 (100%) in the low speed region where the rotational speed is N0 rpm or less, and in the outer speed region within 100 rpm, it gradually decreases below 1 and finally becomes 0 at N1 rpm, and in the high speed region above N1 rpm. Therefore, the effective ripple suppression value Tsup is added to the torque command value Tref only in the resonance speed region (within about N0 rpm) where the torque ripple causes mechanical resonance. Outside the resonance speed region, the target torque Tref * is the torque command Tref itself and there is no reduction in motor efficiency. That is, the torque ripple that causes mechanical resonance is effectively reduced, and there is no unnecessary reduction in motor efficiency. Further, at the rotational speed of N1 rpm or higher where Rn is 0, Th and α are not calculated using the sixth-order function, so the calculation processing load in the high speed region is low.

  FIG. 9 shows the torque ripple reduction effect of the third embodiment. According to the inventor's simulation (desktop calculation), even if a quadratic approximate function is used, the ripple suppression effect is slightly inferior to that of the third embodiment, but in the low torque region, particularly in −T0 to + T0Nm. As in the third embodiment, a sufficient ripple suppressing effect can be obtained. That is, if a second-order or higher approximation function is used, a ripple suppression effect sufficient to prevent the resonance of the wheel can be obtained.

The hardware of the fourth embodiment is the same as that of the third embodiment described above, and the functions are the same. However, “torque ripple suppression” in the fourth embodiment is changed to “torque ripple suppression value calculation” 25b shown in FIG. The ripple phase table 61a of the “torque ripple suppression value calculation” 25b has a sixth-order approximation formula α = α6 · Tref6 + α5 · Tref5 + α4 · Tref4 + α3 · Tref3 + α2 · Tref2 + α1 · Tref1 + α0
The ripple phase value α corresponding to the torque command Tref of the entire torque command region calculated and stored in the memory and outputting the ripple phase value α associated with the given torque command Tref is output. The ripple amplitude table 62a is a sixth-order approximation formula Th = k6 · Tref6 + k5 · Tref5 + k4 · Tref3 + k3 · Tref3 + k2 · Tref2 + k1 · Tref1 + k0.
The ripple amplitude value Th corresponding to the torque command Tref of the entire torque command region calculated in step S1 and stored in the memory is output and the ripple amplitude value Th associated with the given torque command Tref is output. Other functions of the “torque ripple suppression value calculation” 25b are the same as those of the “torque ripple suppression” S9a of the third embodiment, and output substantially the same ripple suppression value Tsup as that of the third embodiment. Other configurations and functions of the fourth embodiment are the same as those of the first embodiment.

It is a block diagram which shows the outline of a structure of 1st Example of this invention. It is a block diagram which shows the outline | summary of a function structure of the motor control apparatus 21 shown in FIG. It is a block diagram which shows the function structure of the torque ripple suppression value calculation 25 shown in FIG. (A) And (b) is a graph which shows the limiting ratios Rt and Rn stored in the limiting ratio table 48 for torque and the limiting ratio table for rotational speed shown in FIG. It is a flowchart which shows the outline | summary of the motor control of the microcomputer MPU shown in FIG. It is a graph which shows the torque suppression effect of 1st Example (Example 1). It is a block diagram which shows the function structure of the torque ripple suppression value calculation 25a of 2nd Example. It is a flowchart which shows the outline | summary of "torque ripple suppression" (S9a) of 3rd Example. It is a graph which shows the torque suppression effect of 3rd Example (Example 3). It is a block diagram which shows the function structure of the torque ripple suppression value calculation 25b of 4th Example. It is a graph which shows a torque ripple when there is no torque ripple suppression of the electric motor 10 shown in FIG. It is a graph which shows a ripple phase and an approximate line when there is no torque ripple suppression of the electric motor 10 shown in FIG. It is a graph which shows a ripple amplitude and an approximate line when there is no torque ripple suppression of the electric motor 10 shown in FIG. It is a graph which shows the relationship between the high efficiency torque curve (thick solid line which goes up to the right) used in vector control which microcomputer MPU shown in FIG. In

Explanation of symbols

10: Electric motors 11-13: Three-phase stator coil 17: Resolver 18: Battery Vdc on vehicle: Primary voltage (battery voltage)
Vuc: secondary voltage (boost voltage)

Claims (12)

A DC power supply; an inverter that controls the exchange of electric power between the DC power supply and the motor; and the inverter so that the output torque of the motor becomes the target torque based on the target torque and rotation speed of the motor. A motor control means for controlling the motor;
Means for deriving a ripple suppression value corresponding to an amplitude value and a phase value of the torque ripple of the motor corresponding to the motor torque, and a rotation angle of the motor; and
In the resonance speed region where the torque ripple causes mechanical resonance in the driven system, the target torque is generated by adding the ripple suppression value to the torque command value so as to cancel the torque ripple, and outside the resonance speed region. Target torque correction means using the torque command value as the target torque;
An electric motor control device comprising: The means for deriving the ripple suppression value is
An amplitude value calculating means for calculating the amplitude value based on a first polynomial that approximates an amplitude value corresponding to the torque of the torque ripple of the electric motor;
The phase value of the torque ripple of the motor is calculated based on a second polynomial that approximates the phase value corresponding to the torque, and the vibration value of the torque ripple having the calculated phase value at the electrical angle of rotation of the motor is calculated. Vibration value calculating means for calculating; and
Suppression value calculation means for calculating a ripple suppression value whose factor is the product of the vibration value and the amplitude value;
An electric motor control device according to claim 1. The means for deriving the ripple suppression value is
An amplitude table on the memory means, comprising amplitude value groups calculated based on a first polynomial that approximates an amplitude value corresponding to torque of the torque ripple of the motor;
A phase table on a memory means comprising a phase value group calculated based on a second polynomial that approximates a phase value corresponding to torque of the torque ripple of the motor;
A vibration value calculation means for reading a phase value and an amplitude value corresponding to the torque of the motor from the phase table and the amplitude table, and calculating a vibration value of the torque ripple having the calculated phase value at an electrical angle of rotation of the motor. ;and,
Suppression value calculation means for calculating a ripple suppression value with the vibration value and the amplitude value as factors;
An electric motor control device according to claim 1.   The motor control device according to any one of claims 1 to 3, wherein the means for deriving the ripple suppression value does not execute the calculation of the ripple suppression value when the motor operation is outside the resonance speed region.   The target torque correction means is configured to cancel the torque ripple when the motor operation is in a predetermined torque region in which the torque ripple is maintained in a mechanical resonance speed region in the driven system or in the resonance speed region. 4. The target torque is generated by adding a ripple suppression value to a torque command value. When the target torque is outside the predetermined torque region and outside the resonance speed region, the torque command value is set as the target torque. The electric motor control device according to any one of the above.   The motor control device according to claim 5, wherein the first polynomial is a linear function that represents the amplitude value of the predetermined torque region by an approximate line.   The motor control device according to claim 5, wherein the second polynomial is a linear function that represents the phase value of the predetermined torque region by an approximate line.   The motor control device according to claim 2 or 3, wherein the first polynomial is a second or higher order polynomial that approximates an amplitude value corresponding to torque.   The motor control device according to claim 2 or 3, wherein the second polynomial is a second or higher order polynomial that approximates a phase value corresponding to torque.   The electric motor control device according to claim 5, 6 or 7, wherein the predetermined torque region is a low torque region.   The motor control device according to claim 1 or 4, wherein the resonance speed region is a predetermined low speed region.   The motor control device according to claim 1, wherein the torque ripple is a sixth harmonic frequency of an output frequency of the inverter with respect to the motor.

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