JP2007124722A - Synchronous motor controller - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a synchronous motor controller which can efficiently perform weakish field control, by deciding the need for weakish field control and suppressing the vibration in velocity of a rotor, in a synchronous motor control which drives a synchronous motor by the vector control of a d-q axis, performing weakish field control. <P>SOLUTION: This synchronous motor controller is equipped with a weakish field deciding unit 8 which outputs a weakish field command signal F<SB>s</SB>, based on the difference signal between a weakish field reference signal r<SB>Vref</SB><SP>*</SP>and a voltage vector amplitude command signal r<SB>V</SB><SP>*</SP>; a voltage vector amplitude limiter 9, which inputs the above voltage vector amplitude command signal r<SB>V</SB><SP>*</SP>and outputs a new voltage vector amplitude command signal r<SB>V1</SB><SP>*</SP>; a d-axis current controller 4 which outputs a d-axis voltage command signal V<SB>d</SB><SP>*</SP>, based on the above weakish field command signal F<SB>s</SB>; and a d-axis voltage compensator 7 which outputs a d-axis voltage compensation signal V<SB>dc</SB>, based on the above weakish field command signal F<SB>s</SB>. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a synchronous motor control device that performs field weakening control and drives a synchronous motor by dq axis vector control.

In general, in the control of a synchronous motor, the d-axis current is set to 0 in order to improve the efficiency during low-speed operation. However, in order to overcome the problem of voltage shortage due to the induced voltage during high-speed operation, a weak magnetic flux control for flowing a negative d-axis current is performed. This is done (for example, see Non-Patent Document 1).
FIG. 4 is a block diagram illustrating a configuration of a current control unit of a conventional synchronous motor control device. In the figure, reference numeral 15 denotes a synchronous motor. Reference numeral 14 denotes a current sensor which detects three-phase currents i _u , i _v and i _w flowing through the armature of the synchronous motor 15. 16 is a position sensor, for detecting the magnetic pole position theta _m of the synchronous motor 15. Reference numeral 12 denotes a three-phase AC / dq coordinate converter, which converts the three-phase currents i _u , i _v , i _w into detection currents I _d , I _q in the dq coordinate format based on the magnetic pole position θ _m. . Reference numeral 19 denotes a d-axis PI controller, which calculates a d-axis voltage command V _d ^* based on a deviation E _Id between the d-axis current command signal I _d ^* and the d-axis current detection signal I _d . A q-axis PI controller 5 calculates a q-axis voltage command V _q ^* based on a deviation E _Iq between the q-axis current command signal I _q ^* and the q-axis current detection signal I _q . Reference numeral 6 denotes a dq / polar coordinate converter. The d and q axis voltage commands V _d ^* and V _q ^* are converted into polar vector voltage vector amplitude command values r _V ^{* as} shown in equations (1) and (2) ^. And a voltage vector phase command value θ _V ^* .
^{_{r V * = √ (V d}} * 2 + V q * 2) (1)
θ _V ^* = tan ⁻¹ (−V _d ^* / V _q ^* ) (2)

Reference numeral 11 denotes a pole / three-phase AC coordinate converter, which converts the voltage vector amplitude command value r _V ^* and the voltage vector phase command value θ _V ^* based on the magnetic pole position θ _m into the three-phase voltage command values v _u ^* and v _v ^*. , V _w ^* . A PWM inverter 13 outputs three-phase voltages v _u , v _v , v _w based on the three-phase voltage commands v _u ^* , v _v ^* , v _w ^* , and drives the motor 15. 17 is an integral compensator for integrating the value obtained by subtracting the voltage vector amplitude command r _V ^* from a predetermined voltage vector amplitude command field weakening reference signal r _Vref ^*. Reference numeral 18 denotes a d-axis current command limiter. The d-axis current command signal I _d ^* is limited to 0 or less.

Since the induced voltage during low-speed operation is small and the voltage vector amplitude command value r _V ^* is smaller than the field weakening reference signal r _Vref ^{* of the} voltage vector amplitude command, the output of the integral compensator 17 becomes a positive value. The command becomes 0. On the other hand, the induced voltage during high-speed operation increases, and the voltage vector amplitude command value r _V ^* becomes larger than the field weakening reference signal r _Vref ^{* of the} voltage vector amplitude command, so that the output of the integral compensator 17 becomes a negative value. Therefore, the d-axis current command is also a negative value.
As described above, the synchronous motor control device according to the prior art makes the d-axis current command negative only when the voltage vector amplitude command value r _V ^* becomes larger than the field weakening reference signal r _Vref ^{* of the} voltage vector amplitude command. By setting the value, the flux-weakening control is performed.
Yoshiki Ito et al., “High Torque Control Method for Permanent Magnet Synchronous Motor in Voltage Saturation Region”, 2004 Annual Conference of the Institute of Electrical Engineers of Japan, August 14, 2004, p. I175-I178

The conventional synchronous motor control device is weakened when the field weakening reference signal of the voltage vector amplitude command is set lower than the voltage vector amplitude saturation value (the maximum value of the voltage vector amplitude for rotating the synchronous motor at a constant speed). Even when the magnetic flux control is not necessary yet, a current is passed through the d-axis, resulting in poor efficiency. Also, when the field weakening reference signal of the voltage vector amplitude command is the voltage vector amplitude saturation value, if the voltage vector amplitude command does not exceed the voltage vector amplitude saturation value, the flux weakening control does not operate and the voltage vector amplitude command When the voltage vector amplitude saturation value is exceeded, the flux-weakening control operates. However, even if the voltage vector amplitude command is constant, the armature voltage vector becomes variable, so the q-axis current becomes oscillating and rotating. There was also a problem that the rotation speed of the child became vibrational.
SUMMARY OF THE INVENTION The present invention has been made in view of such problems, and a synchronous motor control capable of performing field-weakening control efficiently by judging the necessity of field-weakening control and suppressing vibration of the rotor speed. An object is to provide an apparatus.

In order to solve the above problem, the present invention is configured as follows.
According to the first aspect of the present invention, in a synchronous motor control device that performs field weakening control and drives a synchronous motor by dq axis vector control, based on a deviation signal between the field weakening reference signal and the voltage vector amplitude command signal. A field weakening determination device for outputting a field weakening command signal; a voltage vector amplitude limiter for inputting the voltage vector amplitude command signal and outputting a new voltage vector amplitude command signal; and the new voltage vector amplitude The synchronous motor is driven based on a command signal.
According to a second aspect of the present invention, the field weakening determination device according to the first aspect outputs the field weakening command signal for invalidating the field weakening when the deviation is positive, When the deviation is negative, the field weakening command signal for enabling the field weakening is output.
According to a third aspect of the present invention, there is provided a d-axis current controller that outputs a d-axis voltage command signal based on the field weakening command signal according to the first aspect of the invention, and a field weakening command signal. And a d-axis voltage compensator that outputs a d-axis voltage compensation signal.
According to a fourth aspect of the present invention, the d-axis current controller according to the third aspect of the invention includes a current control changeover switch and a current integration buffer, and the current control is performed based on the field weakening command signal. In the case of the field weakening command signal that disables the field weakening by switching the changeover switch, the current control integral gain is multiplied by the d axis current deviation signal that is the deviation between the d axis current command signal and the d axis current detection signal. The field weakening command signal for enabling the field weakening is calculated by adding the multiplication value to the d-axis voltage command integral value that is the output of the current integration buffer and inputting the product to the current integration buffer. In this case, the d-axis voltage command integrated value is input to the current integration buffer, a value obtained by multiplying the d-axis current deviation signal by a current control proportional gain, and the d-axis voltage command integrated value are added, and And it outputs an axis voltage command signal.
According to a fifth aspect of the invention, the current integration buffer according to the fourth aspect of the invention outputs the input value as the d-axis voltage command integration value with a delay of one sample period.
According to a sixth aspect of the invention, the d-axis voltage compensator according to the third aspect of the invention includes a voltage compensation changeover switch, a voltage compensation integration buffer, and a voltage compensation PI controller, and the field weakening command signal In the case of the field weakening command signal for switching the voltage compensation changeover switch to invalidate the field weakening based on the voltage compensation PI controller, the voltage compensation PI controller is set in a standby state, and the d-axis voltage compensation signal is set to 0 (zero). In the case of the field weakening command signal for enabling the field weakening, after resetting the voltage compensation integration buffer once, the voltage compensation PI controller is started and the output of the voltage compensation PI controller is This is a d-axis voltage compensation signal.
According to a seventh aspect of the invention, the voltage compensation PI controller according to the sixth aspect of the invention multiplies a deviation signal between the field weakening reference signal and the voltage vector amplitude command signal by a voltage compensation integral gain. A multiplication value is calculated, the multiplication value is added to the d-axis voltage compensation integration value that is an output of the voltage compensation integration buffer, and the multiplication value is input to the current integration buffer. The field weakening reference signal and the voltage vector amplitude command signal And a value obtained by multiplying the deviation signal by a voltage compensation proportional gain and the d-axis voltage compensation integral value are added to output the d-axis voltage compensation signal.
According to an eighth aspect of the present invention, the voltage compensation buffer according to the sixth aspect of the invention outputs the input value as the d-axis voltage compensated integral value delayed by one sample period.
According to a ninth aspect of the present invention, the field weakening reference signal according to the first aspect of the invention is a voltage vector amplitude saturation value, and the voltage vector amplitude limiter is the voltage vector amplitude saturation value and the voltage. The vector amplitude command signal is limited.

According to the invention described in any one of claims 1, 2, and 9, the necessity of field weakening control can be determined, and the voltage vector amplitude command signal is limited to the voltage vector amplitude saturation value, which is stable and necessary minimum. A limited d-axis current can be supplied, and field weakening control can be performed efficiently and by suppressing vibration of the rotor speed.
In addition, according to the invention of any one of claims 3 to 8, when the voltage vector amplitude command signal is within the voltage vector amplitude saturation value, the d-axis current command is set to 0 to perform normal current control efficiently. The synchronous motor can be rotated. If the voltage vector amplitude command signal exceeds the voltage vector amplitude saturation value, the output of the integrator of the d-axis current controller is held, the d-axis voltage compensator is started, and the d-axis voltage compensation signal is transferred to the d-axis voltage command. In addition to the new d-axis voltage command, the voltage vector amplitude command signal is limited to the voltage vector amplitude saturation value, and a stable and necessary d-axis current can be flowed to smoothly weaken and control the magnetic flux. Therefore, the synchronous motor can be rotated at a high speed by suppressing the vibration of the rotor speed.

Hereinafter, embodiments of the present invention will be described with reference to the drawings.
FIG. 1 is a block diagram of a current control unit of a synchronous motor control apparatus showing an embodiment of the present invention. In the figure, reference numeral 15 denotes a synchronous motor. Reference numeral 14 denotes a current sensor which detects three-phase currents i _u , i _v and i _w flowing through the armature of the synchronous motor 15. Although an example of detecting a three-phase current is shown here, two-phase current detection may be detected, and the remaining one-phase current may be calculated by calculation. 16 is a position sensor, for detecting the magnetic pole position theta _m of the synchronous motor 15. Reference numeral 12 denotes a three-phase AC / dq coordinate converter, which converts the three-phase currents i _u , i _v , i _w into detection currents I _d , I _q in the dq coordinate format based on the magnetic pole position θ _m. .

Reference numeral 4 denotes a d-axis current controller, which calculates a d-axis voltage command V _d ^* based on a deviation E _Id between the d-axis current command signal I _d ^* and the d-axis current detection signal I _d and a field weakening command signal F _s. To do. 3 is an adder, by adding the d-axis voltage compensation signal _{V dc} and outputs the new d-axis voltage command _{V d1} ^* in the d-axis voltage command _V ^{d *.} A q-axis PI controller 5 calculates a q-axis voltage command V _q ^* based on a deviation E _Iq between the q-axis current command signal I _q ^* and the q-axis current detection signal I _q . Reference numeral 6 denotes a dq / polar coordinate converter, where V _d1 ^* and V _q ^* are the voltage vector amplitude command value r _V ^* and the voltage vector phase command value in the polar coordinate format as shown in the equations (1) and (2). Convert to θ _V ^* . 9 the voltage is the vector amplitude limiter, and outputs the voltage vector amplitude command r _V ^* to the voltage vector magnitude saturation value r is limited within _m new voltage vector amplitude command value r _V1 ^*. Reference numeral 11 denotes a pole / three-phase AC coordinate converter, which converts a new voltage vector amplitude command value r _V1 ^* and a voltage vector phase command value θ _V ^* based on the magnetic pole position θ _m into a three-phase voltage command value v _u ^* , v. _v ^*, _v is converted to ^{w *.}

A PWM inverter 13 outputs three-phase voltages v _u , v _v , v _w based on the three-phase voltage commands v _u ^* , v _v ^* , v _w ^* , and drives the motor 15. Reference numeral 8 denotes a field weakening determination unit that outputs a field weakening command signal F _s based on the difference E _r between the field weakening reference signal r _Vref ^* of the voltage vector amplitude command and the voltage vector amplitude command value r _V ^*. . Reference numeral 7 denotes a d-axis voltage compensator, which calculates a d-axis voltage compensation signal V _dc based on E _r and F _s .
The present invention is different from Non-Patent Document 1 in that a field weakening determination unit that outputs a field weakening command signal based on a deviation signal between the field weakening reference signal and the voltage vector amplitude command signal, and the voltage vector amplitude A voltage vector amplitude limiter that inputs a command signal and outputs a new voltage vector amplitude command signal, a d-axis current controller that outputs a d-axis voltage command signal based on the field weakening command signal, and the field weakening A d-axis voltage compensator that outputs a d-axis voltage compensation signal based on the command signal is provided.
Thus, instead of changing the d-axis current command I _d ^* as in the prior art, the I _d ^* always zero, if the voltage vector amplitude command r _V ^* has exceeded the voltage vector magnitude saturation value r _m changing the d-axis voltage command, also is to produce a voltage vector amplitude command r _V ^* a new voltage vector amplitude command value is limited within the voltage vector magnitude saturation value r _m through a limiter r _V1 ^*.

The field weakening determination unit 8 determines the field weakening command signal F _s if the difference E _r between the field weakening reference signal r _Vref ^* of the voltage vector amplitude command and the voltage vector amplitude command value r _V ^* is a positive value. It is invalidated, and enable the field weakening command signal F _s if E _r is a negative value.
Although FIG. 1 only describes the current control unit which is the main part of the present invention, the synchronous motor control device is originally configured by the presence of a speed control unit (not shown), a position control unit (not shown), and the like. is doing. Since the well-known structure can be used for the structure not shown, description is abbreviate | omitted.

FIG. 2 is a block diagram showing the configuration of the d-axis current controller of the synchronous motor control apparatus according to the embodiment of the present invention. In the figure, 41 is a current control proportional gain, which outputs a proportional term V _pd ^* of a d-axis voltage command obtained by multiplying E _Id by K _pd . _{Reference numeral} 42 denotes a current control integral gain, which outputs a value obtained by multiplying E _Id by _Kid . Reference numeral 43 denotes an adder that adds the integral term V _id ^* of the d-axis voltage command to the output of the current control integral gain 42. 46 is a current control changeover switch that outputs the output of the adder 43 when the field weakening command signal F _s is invalid, and outputs the integral term V _id ^* of the d-axis voltage command when F _s is valid. . Reference numeral 45 denotes a current control integration buffer, which outputs the output of the current control switch 46 as an integral term V _id ^* of the d-axis voltage command with a delay of one sample period. An adder 44 adds the integral term V _id ^* of the d-axis voltage command and the proportional term V _pd ^* of the d-axis voltage command and outputs the result as a d-axis voltage command signal V _d ^* .

FIG. 3 is a block diagram showing the configuration of the d-axis voltage compensator of the synchronous motor control device according to the embodiment of the present invention. In the figure, reference numeral 77 denotes a zero signal, which outputs 0 (zero). Reference numeral 78 denotes a voltage compensation PI controller, which enters a standby state when the field weakening command signal F _s is invalid, and is activated when F _s is valid and starts calculation. A voltage compensation changeover switch 76 outputs 0 when F _s is invalid, and outputs the output of the voltage compensation PI controller 78 as a d-axis voltage compensation signal V _dc when F _s is valid. A voltage compensation proportional gain 71 multiplies _Er by K _pc and outputs a proportional term V _pc of the d-axis voltage compensation signal. Reference numeral 72 denotes a voltage compensation integral gain, which outputs a value obtained by multiplying _Er by _Kic . An adder 73 adds the integral term V _ic of the d-axis voltage compensation signal to the output of the voltage compensation integral gain 72. Reference numeral 75 denotes a voltage compensation integration buffer, which is reset when the field weakening command signal F _s is switched from invalid to valid, and the output of the adder 73 is delayed by one sample period and the integral term V _ic of the d-axis voltage compensation signal. Output as. An adder 74 adds the integral term V _ic of the d-axis voltage compensation signal and the proportional term V _pc of the d-axis voltage compensation signal and outputs the result as a d-axis voltage compensation signal V _dc . Note that the reset in the voltage compensation integration buffer 75 means that the value in the voltage compensation integration buffer 75 is cleared to 0 (zero).

Hereinafter, the operation principle of the current control unit of the synchronous motor control device according to the embodiment of the present invention will be described.
Since the field weakening command signal F _s is invalid when the voltage vector amplitude command value r _V ^* is equal to or less than the field weakening reference signal r _Vref ^{* of the} voltage vector amplitude command, d is the output of the d-axis voltage compensator. Since the shaft voltage compensation signal V _dc becomes 0 and the d-axis current controller operates in the same manner as an ordinary PI controller, the entire control system is the same as the control system that does not perform the flux-weakening control.
On the other hand, when the voltage vector amplitude command value r _V ^* is equal to or greater than the field weakening reference signal r _Vref ^{* of the} voltage vector amplitude command, the field weakening command signal F _s becomes effective. At this time, since the integral term of the d-axis voltage command is unchanged, the d-axis feedback current I _d does not follow the d-axis current command I _d ^* = 0 without a steady deviation. In this case, the d-axis voltage compensator 7 determines that the negative d-axis voltage compensation signal V _dc is based on the difference E _r between the field weakening reference signal r _Vref ^* of the voltage vector amplitude command and the voltage vector amplitude command value r _V ^*. , And a negative d-axis armature current can be passed to rotate the rotor at a high speed.
Moreover, even given a field weakening reference signal r _Vref of the voltage vector amplitude command ^* as voltage vector amplitude saturation value r _m, ^{when *} the voltage vector amplitude command r _V exceeds the voltage vector magnitude saturation value r _m, since is provided a voltage vector magnitude limiter 9, so ^* new new voltage vector amplitude command value input to the pole / three-phase AC coordinate converter 11 r _V1 is the voltage vector magnitude saturation value r _m, the rotor It can be rotated at a constant speed.

As described above, when the voltage vector amplitude command signal is within the voltage vector amplitude saturation value, the d-axis current command is set to 0 and normal current control is performed, whereby the synchronous motor can be efficiently rotated.
On the other hand, when the voltage vector amplitude command signal exceeds the voltage vector amplitude saturation value, the output of the integrator of the d-axis current controller is held, the d-axis voltage compensator is started, and the d-axis voltage compensation signal is transferred to the d-axis voltage command. In addition to the new d-axis voltage command, the voltage vector amplitude command signal is limited to the voltage vector amplitude saturation value, and a stable and necessary d-axis current can be flowed to smoothly weaken and control the magnetic flux. The synchronous motor can be rotated at high speed with high efficiency and no vibration.

Next, the effect of the present invention will be described using simulation results.
FIG. 5 is a diagram showing a simulation result of speed control when field-weakening control is not performed in the conventional synchronous motor control device, and FIG. 6 is an enlarged view of a part of FIG. FIG. 7 is a diagram showing a simulation result of speed control in the conventional synchronous motor control device, and FIG. 8 is an enlarged view of a part of FIG. FIG. 9 is a diagram showing a simulation result of speed control in the synchronous motor control device of the present invention, and FIG. 10 is a partially enlarged view of FIG.
In each figure, it is a waveform diagram when a certain speed command is input. The lower stage is the speed command and the rotor speed, the middle stage is the d-axis armature current and the q-axis armature current, and the upper stage is the armature voltage vector amplitude and voltage. A vector amplitude saturation value is shown.

In FIG. 6, it can be seen that there is a steady deviation between the speed command and the rotor speed. Also, in FIG. 8, it can be seen that the rotor speed is oscillatory although no steady deviation remains between the speed command and the rotor speed. On the other hand, in FIG. 10, it can be seen that there is no stationary deviation between the speed command and the rotor speed, and that the rotor speed hardly oscillates. Thus, it can be said that there is a great effect of driving the synchronous motor in the synchronous motor control device of the present invention.

The block diagram of the current control part of the synchronous motor control apparatus which shows the Example of this invention The block diagram which shows the structure of the d-axis current controller of the synchronous motor control apparatus of this invention The block diagram which shows the structure of the d-axis voltage compensator of the synchronous motor control apparatus of this invention The block diagram which shows the structure of the current control part of the synchronous motor control apparatus of a prior art The figure which shows the simulation result of the speed control when not performing field-weakening control in the synchronous motor control device of the prior art 5 is an enlarged view of a part of FIG. The figure which shows the simulation result of the speed control in the synchronous motor control device of the prior art 7 is an enlarged view of a part of FIG. The figure which shows the simulation result of the speed control in the synchronous motor control apparatus of this invention 9 is an enlarged view of a part of FIG.

Explanation of symbols

1, 2, 10 Subtractor 3, 43, 44, 73, 74 Adder 4 d-axis current controller 5 q-axis PI controller 6 dq / polar coordinate converter 7 d-axis voltage compensator 8 field weakening determination device 9 Voltage vector amplitude limiter 11 Pole / 3-phase AC coordinate converter 12 3-phase AC / dq coordinate converter 13 PWM inverter 14 Current sensor 15 Synchronous motor 16 Position sensor 17 Integral compensator 18 d-axis current command limiter 19 d-axis PI controller 41 Current control proportional gain 42 Current control integral gain 45 Current control integral buffer 46 Current control changeover switch 71 Voltage compensation proportional gain 72 Voltage compensation integral gain 75 Voltage compensation integral buffer 76 Voltage compensation integral buffer 77 Zero signal 78 Voltage compensation PI Controller

Claims (9)

In a synchronous motor control device that performs field weakening control and drives a synchronous motor by dq axis vector control,
A field weakening determiner that outputs a field weakening command signal based on a deviation signal between the field weakening reference signal and the voltage vector amplitude command signal;
A voltage vector amplitude limiter that inputs the voltage vector amplitude command signal and outputs a new voltage vector amplitude command signal;
A synchronous motor control device that drives the synchronous motor based on the new voltage vector amplitude command signal. The field weakening determination device, when the deviation is positive, outputs the field weakening command signal to invalidate the field weakening,
2. The synchronous motor control device according to claim 1, wherein when the deviation is negative, the field weakening command signal for enabling the field weakening is output. A d-axis current controller that outputs a d-axis voltage command signal based on the field weakening command signal;
The synchronous motor control device according to claim 1, further comprising a d-axis voltage compensator that outputs a d-axis voltage compensation signal based on the field weakening command signal. The d-axis current controller includes a current control changeover switch and a current integration buffer;
Based on the field weakening command signal, switching the current control changeover switch,
In the case of the field weakening command signal invalidating the field weakening, the multiplication value is calculated by multiplying the d-axis current deviation signal, which is the deviation between the d-axis current command signal and the d-axis current detection signal, by the current control integral gain. And adding the multiplication value to the d-axis voltage command integration value, which is the output of the current integration buffer, and inputting it to the current integration buffer,
In the case of the field weakening command signal that activates the field weakening, the d-axis voltage command integrated value is input to the current integration buffer,
4. The synchronization according to claim 3, wherein the d-axis voltage command signal is output by adding a value obtained by multiplying the d-axis current deviation signal by a current control proportional gain and the d-axis voltage command integrated value. Electric motor control device. 5. The synchronous motor control device according to claim 4, wherein the current integration buffer outputs the input value as the d-axis voltage command integrated value with a delay of one sample period. The d-axis voltage compensator includes a voltage compensation changeover switch, a voltage compensation integration buffer, and a voltage compensation PI controller.
Based on the field weakening command signal, switch the voltage compensation switch,
In the case of the field weakening command signal for invalidating the field weakening, the voltage compensation PI controller is set in a standby state, the d-axis voltage compensation signal is set to 0 (zero),
In the case of the field weakening command signal for enabling the field weakening, the voltage compensation integration buffer is reset once, then the voltage compensation PI controller is started, and the output of the voltage compensation PI controller is set to the d-axis. 4. The synchronous motor control device according to claim 3, wherein the synchronous motor control device is a voltage compensation signal. The voltage compensation PI controller calculates a multiplication value by multiplying a deviation signal between the field weakening reference signal and the voltage vector amplitude command signal by a voltage compensation integral gain, and outputs a d-axis voltage which is an output of the voltage compensation integral buffer. Add the multiplication value to the compensation integral value and input to the current integration buffer,
A value obtained by multiplying a deviation signal between the field-weakening reference signal and the voltage vector amplitude command signal by a voltage compensation proportional gain and the d-axis voltage compensation integral value are added to output the d-axis voltage compensation signal. The synchronous motor control device according to claim 6.   The synchronous motor control device according to claim 6, wherein the voltage compensation buffer outputs the input value as the d-axis voltage compensation integral value with a delay of one sample period. The field weakening reference signal is a voltage vector amplitude saturation value;
The synchronous motor control device according to claim 1, wherein the voltage vector amplitude limiter limits the voltage vector amplitude command signal with the voltage vector amplitude saturation value.

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