JP2008253093A - Electric motor controller and control method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an electric motor controller for eliminating a necessity of an expensive microcomputer, and having a current control system for improving a response to a current. <P>SOLUTION: The electric motor controller comprises: a first sample-hold device for sampling and detecting an output current at timing in synchronization with a carrier signal; a current controller for implementing a control for matching an instruction current with the output current; a PWM pulse generator for comparing a voltage instruction calculated by using an output from the current controller with the carrier signal, and converting a comparison result into a PWM pulse; a second sample-hold device for sampling the instruction current at timing in synchronization with the carrier signal; a voltage compensator for calculating a voltage compensation based on an output from the second sample-hold device; and an adder for adding the voltage instruction to an output from the voltage compensator, and generating a new voltage instruction. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to a motor control device and a control method including an inverter device that supplies power to a motor by PWM pulses.

  The conventional motor control device takes into account the periodicity of the pulsation component included in the current detection value when sampling the current command value and the current detection value and calculates the manipulated variable, and thus the current command value is sampled more than the cycle of sampling the current command value. The current detection value is sampled at a long period, while the operation amount is calculated at a short period in accordance with the sampling period of the current command value (see, for example, Patent Document 1). In addition, compensation is made so that the current value obtained by current sampling and holding at a time position a predetermined time before the positive and negative vertex time positions of the triangular wave is close to the current value at the triangular wave vertex time position. A voltage command value is generated by executing a current control calculation for the added current value, and the voltage command value is updated in synchronization with the apex time position of the triangular wave to provide a PWM pulse pattern (for example, patent document) 2).

  In FIG. 7, 101 is a control device that controls the power converter 102 based on the command value and the current detection value, 102 is a power converter that drives the load device 103, 103 is a load device to be controlled, and 104 detects current. And a command value generator 105 for outputting a current command value. The control device 101 includes a sample / hold device (1) 112 for sampling a current detection value, a sample / hold device (2) 114 for sampling a command value, a sample signal 111 for sampling the current detection value, and a command value A sample signal generator 115 for generating a sample signal 113 for performing a voltage command, a voltage command calculator 116 for calculating a voltage command, a PWM controller 117 for comparing the output of the voltage command calculator with a triangular wave carrier, and creating a PWM pulse, a voltage It comprises a comparator 271 that compares the command value with the triangular wave carrier, a triangular wave generator 272 that generates a triangular wave carrier, and a synchronizing signal 118 for synchronizing the output of the triangular wave carrier and the sample signal generator.

  When the current command value of the load device 103 is generated from the command value generator 105, the control device 101 converts the output of the current detector 104 and the output of the command value generator 105 into the sample / hold device (1) 112 and the sample / hold device, respectively. The voltage command value is read by the voltage command calculator 116. In this case, the sample period of the sample signal 111 of the sample and hold unit (1) is different from that of the sample signal 113 of the sample and hold unit (2). The command value and the detected value are sampled at different periods, and the respective values are read. . These sample periods are determined by the arithmetic processing capability of the control device 101. The PWM controller 117 compares the output of the voltage command calculator 116 with the triangular wave carrier output from the triangular wave generator 272 by the comparator 271 and generates a PWM pulse. At this time, the triangular wave carrier and the sample signal are synchronized by the synchronization signal 118. The PWM pulse output from the PWM controller 117 drives the power converter 102 and controls the load device 103.

As described above, the conventional motor control device detects the current at the timing of the peak of the triangular wave carrier and samples the command value in a short cycle, thereby eliminating the high-frequency pulsation component in the current detection and controlling the current value. It improves the response characteristics of the system.
JP-A-9-154283 (FIG. 1) JP 2005-31274 A (FIG. 1)

  In the conventional motor current control device, the cycle for sampling the command value and the detection value and the cycle for calculating the voltage command are determined by the calculation processing capability of the control device, and in order to achieve high response, the cycle is as short as possible. Therefore, in order to make the current control respond at high speed, there is a problem that an expensive microcomputer with high processing capacity is required. In addition, when the current value is sampled and held at a time position a predetermined time before the positive and negative vertex time positions of the triangular wave, the current detection is shifted from the vertex of the carrier, so that it is also affected by carrier noise. It becomes easy. In addition, it is necessary to predict the values of the sampled and held current signals at the positive and negative vertices of the triangular wave, and the calculation load increases due to this prediction, and there is no margin for the load distribution of the microcomputer. The system still has the problem of requiring an expensive microcomputer.

  The present invention has been made in view of such problems, and an object of the present invention is to provide an electric motor control device having a current control system with improved current response without requiring an expensive microcomputer. .

In order to solve the above problem, the present invention is configured as follows.
According to the first aspect of the present invention, there is provided a first sample-and-hold device that samples and detects an output current flowing through an electric motor at a timing synchronized with a carrier signal, and a current that is controlled so that the command current matches the output current. A controller, a PWM pulse generator that compares a voltage command calculated using the output of the current controller with the carrier signal and converts the voltage command into a PWM pulse, and supplies electric power to the motor using the PWM pulse In the electric motor control device including a power converter, the second sample and hold device that samples the command current at a timing synchronized with the carrier signal, and the second sample and hold device are synchronized with the carrier signal. The command current is sampled even after a predetermined time Δt from the timing when the second sample ho And a voltage compensator for calculating a voltage compensation amount based on the output of the voltage compensator, and an adder for adding the output of the voltage compensator to the voltage command to obtain a new voltage command. It is.

According to a second aspect of the present invention, in the first aspect of the present invention, the current controller and the voltage compensator are configured by proportional / integral control, and the ratio between the two proportional gains and the integral gain is equal. It is a feature.
According to a third aspect of the present invention, in the first aspect of the present invention, the ratio of the proportional gain of the current controller and the proportional gain of the voltage compensator is a relationship between the period of the carrier signal and the predetermined time Δt. From the above, it is obtained by calculation.
According to a fourth aspect of the present invention, in the first aspect of the present invention, the timing for sampling the output current is both or one of peak values (peaks or valleys) of the carrier signal. It is a feature.

The invention according to claim 5 is characterized in that the timing at which the PWM pulse reflecting the new voltage command is supplied to the electric motor is immediately after the completion of the calculation of the new voltage command. is there.
According to a sixth aspect of the present invention, the voltage compensator includes a delay circuit that holds the command current detected in the previous sampling, the command current detected in the sampling after a predetermined time Δt, and the output of the delay circuit. A subtractor that calculates the difference between the subtractor, a multiplier that multiplies the output of the subtractor by a predetermined gain determined by a motor constant without using proportional / integral control, and an output of the multiplier that An adder for adding to the input value is provided.
According to a seventh aspect of the present invention, the voltage compensator includes a delay circuit that holds the command current detected in the previous sampling, and a difference between the command current detected in the current sampling and the output of the delay circuit. A multiplier for multiplying the output of the subtracter by a predetermined gain, and an adder for which the output of the multiplier is proportionally / integratedly controlled and added to the input value of the current controller. It is characterized by this.

  The invention according to claim 8 is the first sample-and-hold device that detects the output current by sampling the output current flowing through the motor at a timing synchronized with the carrier signal, and the command current and the output current match. A current controller that controls the output of the current controller, a PWM pulse generator that compares a voltage command calculated using the output of the current controller with the carrier signal and converts it into a PWM pulse, and the electric motor that uses the PWM pulse. In the electric motor control device including a power converter for supplying electric power to the second sample-and-hold device, a second sample-and-hold device that samples the command current at a timing synchronized with the carrier signal, and the first and second sample-and-hold devices So that the command current and the output current are sampled even after a predetermined time Δt from the timing synchronized with the carrier signal. A first voltage compensator for calculating a compensation amount based on the output of the first sample and hold unit at the predetermined time Δt, and the second sample and hold unit at the predetermined time Δt. And a second voltage compensator that calculates a compensation amount based on the output of the first voltage adder, and an adder that adds the outputs of the first and second voltage compensators to the voltage command to obtain a new voltage command. It is characterized by this.

In order to solve the above problem, the present invention is as follows.
The invention according to claim 9 is a sample-and-hold device that samples the command current at a timing synchronized with the carrier signal, a current controller that controls the command current and the output current to coincide with each other, and A motor control comprising a PWM pulse generator that compares a voltage command calculated using an output with the carrier signal and converts the voltage command into a PWM pulse, and a power converter that supplies power to the motor using the PWM pulse. In the apparatus control method, the command current is sampled at a timing synchronized with the carrier signal, the command current is sampled after a predetermined time Δt, and based on the two command currents sampled during the predetermined time Δt. The voltage compensation amount is calculated, and the voltage compensation amount is added to the voltage command to obtain a new voltage command. It was.

  According to the present invention, it is possible to reduce the dead time in reading the command amount or detection amount used for the current control calculation and output the current control calculation result to the motor, and to compensate for the voltage command in consideration of the effect of the dead time. This can be done without the need for a computer, and the current control response can be improved.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings.

  FIG. 1 is a block diagram of a control device for an electric motor according to the present invention. In the figure, 1 is an electric motor, 2 is an inverter that outputs a voltage for driving the electric motor, 3 is a PWM pulse that compares a voltage command to the electric motor 1 with a carrier signal, and converts a voltage pattern output by the inverter 2 into a PWM pulse. Generator 4 is a triangular wave carrier generator that determines the PWM period of the PWM pulse generator, 5 is a d-axis, q-axis voltage command (Vd *, Vq *) U, V, W command voltage (Vu *, Vv *) , Vw *), a two-phase three-phase converter 6, a current sampling timing generator 6 for determining a current sampling timing based on a triangular wave carrier, and 7 A and 7 B current detectors for detecting the output current of the motor, 8 Is a sample-and-hold device (1) that samples and holds the output current detected by 7A and 7B, and outputs Iu_fb and Iv_fb, and 9 is the phase current Iu_fb and Iv_ A three-phase two-phase converter that converts b into d-axis and q-axis output currents (Id_fb, Iq_fb), and 10 is a q-axis current controller that controls the q-axis command current Iq * and the q-axis output current Iq_fb to match. , 11 is a d-axis current controller that controls the d-axis command current Id * and the d-axis output current Iq_fb of the motor to coincide with each other, 12 is a q-axis voltage compensator, 13 is a d-axis voltage compensator, and 14A and 14B are The sample-and-hold devices (2) and (3), 15A, 15B that output the q-axis command current Iq * and the d-axis command current Id *, respectively, are the difference between the q-axis command current Iq * and the q-axis output current Iq_fb, A subtractor that calculates the difference between the d-axis command current Id * and the d-axis output current Id_fb. 16A adds the output of the q-axis current controller 10 and the output of the q-axis voltage compensator 12, and the q-axis voltage command Vq. Adder for calculating *, 16 Denotes an adder which adds the outputs of the d-axis voltage compensator 13 of d-axis current controller 11, calculates a d-axis voltage command Vd *.

The q-axis voltage compensator 12 includes a delay circuit 12A, a subtractor 12B, and a compensator 12C, calculates a q-axis voltage compensation amount using the difference amount of the q-axis command current Iq *, and inputs the q-axis voltage compensation amount to the adder 16A. Similarly, the d-axis voltage compensator 13 calculates the d-axis voltage compensation amount and inputs it to the adder 16B.
The main part of the present invention that differs from the prior art is that the q-axis command current Iq *, the d-axis command current Id * and the phase current (for example, Iu_fb, Iv_fb) are sampled, and the q-axis command current Iq *, d-axis The voltage compensation amount calculated based on each difference amount of the command current Id * is added to the output of each current controller. With such a configuration, the change amount of the read command current is used. Thus, the dead time (time from the current command read timing to the timing at which the voltage command is output to the motor) due to the command current read is compensated.

Next, referring to FIGS. 1 and 2, the timing and operation of command current and output current sampling, and output of a voltage command to the motor will be described.
The current sampling timing generator 6 knows the peak timing of the triangular wave carrier from the synchronization signal 20 from the triangular wave carrier generator 4, and the sample signal 21A is sampled at the peak of the triangular wave carrier (both the peak and valley of the triangular wave). In addition to the timing of the sample signal 21A, the signal 21B is also output after a predetermined time Δt from the output of the sample signal 21A.
The sample and hold unit (1) 8 samples the phase currents Iu_fb and Iv_fb at the timing of the sample signal 21A, and the sample and hold units (2) 14A and (3) 14B are q-axis command currents at the timing of the sample signal 21B. Iq * and d-axis command current Id * are sampled. After sampling Iq * and Id *, q-axis and d-axis current control and then voltage compensation calculation are performed, and their outputs are input to adders 16A and 16B. The adder 16A adds the q-axis current control 10 output and the q-axis voltage compensation amount 12, and the adder 16B adds the d-axis current control 11 output and the d-axis voltage compensation amount 13 to obtain the q-axis voltage command Vq * and the d-axis voltage command. Vd * is calculated.

Next, a current controller for controlling the command current and the output current to coincide with each other and a voltage compensator for calculating a compensation amount for dead time caused by reading the command current will be described in detail.
Hereinafter, the q-axis current controller 10 and the q-axis voltage compensator 12 will be described, and the descriptions of the d-axis current controller 11 and the d-axis voltage compensator 13 that are different in the amount of control but have the same arithmetic processing will be described. Omitted.
Q-axis having Iq_ref indicating q-axis command current Iq * sampled by sample signal 21B created by current sample timing generator 6 and q-axis output current Iq_fb obtained by three-phase to two-phase conversion of phase currents Iu_fb and Iv_fb In the current controller 10, proportional / integral control (hereinafter abbreviated as PI control) is performed. Assuming that the output of the q-axis current controller 10 is V1, the proportional gain at that time is Kp1, and the integral gain is Ki1, the equation is expressed by the following equation (1).

In the q-axis voltage compensator 12 which receives Iq_ref ′ indicating the q-axis command current Iq * sampled by the sample signal 21B and Iq_ref indicating the previously sampled q-axis command current Iq * after the predetermined time Δt, PI Control is performed. Assuming that the output of the q-axis voltage compensator 12 is V2, the proportional gain at that time is Kp2, and the integral gain is Ki2, the calculation formula is given by formula (2).

The output V1 of the q-axis current controller 10 and the output V2 are added to the q-axis voltage compensator 12, and a new q-axis voltage command Vq * is created. In this way, the voltage compensation amount is calculated using the change amount of the command current, and the compensation voltage is added to the voltage command of the current controller output.
In the calculation of the d-axis voltage compensator 13, the calculation of the d-axis voltage compensator 13 can be omitted in a region or condition where the d-axis current command value does not change.
Also, if the proportional gain and integral gain of each of the current controller and voltage compensator are determined so as to satisfy the relationship of equation (3), the dead time caused by reading the command current using the change amount of the read command current However, the reason for this will be described later.
k = Kp2 / Kp1 = Ki2 / Ki1 (3)
Since the processing is performed in this way, the voltage compensation amount can be calculated using the change amount of the command current, and the current control response can be improved by adding compensation to the voltage command which is the output of the current controller.

Next, compensation for the gain ratio k shown in the equation (3) and the above-described dead time will be described.
The q-axis voltage compensator 12 attempts to compensate for the dead time from sampling of the q-axis command current Iq * to the time when the command voltage is supplied to the electric motor 1 with the voltage compensation amount. That is, the amount of change between Δt in the current command is to compensate for the timing from when the voltage is actually supplied to the motor after a predetermined time Δt. Therefore, the amount of change in the current command during the predetermined time Δt may be compensated by a ratio between the predetermined time Δt and the time until the voltage is actually supplied to the electric motor 1 after the predetermined time Δt. .
Therefore, since the relationship between the predetermined time Δt and the carrier cycle T is obtained as described later, the time from when the voltage is actually supplied to the electric motor 1 after the predetermined time Δt, the gain ratio k is the q-axis command current Iq *. The amount of change, the predetermined time Δt, and the carrier period T can be obtained.

Next, the relationship between the time after the predetermined time Δt is actually supplied to the electric motor 1 and the predetermined time Δt and the carrier cycle T will be described with reference to FIG.
FIG. 3 shows the timing at which a voltage is actually supplied to the motor 1 with respect to the relationship between the carrier period T, the predetermined time Δt, and the peak of the triangular wave carrier (both peaks and valleys of the triangular wave). FIG. 3 also shows the timings of the sampling signals 21A and 21B, the current control calculation, and the voltage compensation calculation.
The PWM pulse generator 3 that generates a gate signal to be supplied to the inverter 2 generates a gate signal by comparing the U, V, and W command voltages (Vu *, Vv *, Vw *) with a triangular wave carrier. The timing at which the voltage is actually supplied is the midpoint between the peaks and valleys of the triangular wave carrier.

From the above description, it can be seen that the time from when the predetermined time Δt is reached until the voltage is actually supplied to the electric motor 1 is (T / 4−Δt), and the gain ratio k is obtained by the equation (4).

When the carrier period T is 100 μs and the predetermined time Δt is 5 μs, k = 4.

However, since the value of k may be determined by factors such as the operation delay of the power elements used in the current detectors 7A and 7B and the inverter 2, it may not be determined uniformly by the calculation of the above equation (4). May be adjusted by looking at the actual current waveform or current response.
Since processing is performed in this manner, it is possible to compensate for a delay from the sampling of the command current until the command voltage is actually supplied to the electric motor.

FIG. 4 is a block diagram showing a configuration of a q-axis voltage compensator 12 ′ and a d-axis voltage compensator 13 ′ showing another embodiment of the present invention. The q-axis voltage compensator 12 and the d-axis voltage compensator 13 in FIG. 1 are replaced with a q-axis voltage compensator 12 ′ and a d-axis voltage compensator 13 ′.
The q-axis voltage compensator 12 ′ and the d-axis voltage compensator 13 ′ are the coefficients of the compensators 12 C and 13 C that are configured by the PI controller in the q-axis voltage compensator 12 and the d-axis voltage compensator 13. 12D, 12E, 12F, 13D, 13E, 13F, adders 12H, 12I, 13H, a subtractor 13I and multipliers 12G, 13G, or a speed detector attached to the motor 1 (not shown) An output frequency ω obtained based on the electric angular velocity of the electric motor obtained from the position detector is inputted.

Next, the setting values of each coefficient unit will be described.
When the electric motor 1 to be driven is, for example, a synchronous motor (especially an SPM motor), the voltage equation of the electric motor is expressed by the equation (5).

Here, p is the differential operator, R and L are the resistance and inductance of the armature winding, Ke is the induced voltage constant, and ω is the output frequency.

Assuming that the amount of change during the predetermined time Δt is ΔIq for the q-axis command current, ΔId for the d-axis command current, and ΔVq and ΔVd, respectively, the voltage compensation amounts to be compensated due to this are The relationship (6) is derived.

Accordingly, ΔVd is calculated by setting the set values of the coefficient multipliers 12D, 12E, and 12F to L / Δt, k × R, and k × L, respectively, and ΔVq is set to the coefficient units 13D, 13E, and 13F with the same set values. Therefore, the command current delay can be compensated.

When ΔIq and ΔId are large, Equation (6) can be approximated to Equation (7), so that the set values of the coefficient multipliers 12E, 12F, 13E, and 13F become 0, and as a result, the adders 12H, 12I, and 13H The subtractor 13I and the multipliers 12G and 13G may be omitted.

In the above description, the motor 1 is described as an SPM motor among the synchronous motors. However, even a synchronous motor such as an IPM motor or another motor such as an induction motor may be calculated using a voltage equation suitable for the motor. .
Since the processing is performed in this way, the present invention can be implemented even if the processing in the q-axis voltage compensator 12 ′ and the d-axis voltage compensator 13 ′ is not PI calculation.

FIG. 5 is a timing chart showing another embodiment of the present invention. FIG. 5 omits the sampling of the command current after a predetermined time Δt from the timing chart of FIG. The command current sampling timing is the same as the output current sampling timing, and both the command current and the output current are sampled only at the peak of the triangular wave carrier (both peaks and valleys of the triangular wave).
The amount of change in the command current at a predetermined time is obtained as the amount of change in the current control cycle, or in other words, the half of the carrier cycle T, and the voltage command to the motor after the command current is sampled. The gain ratio k of the voltage compensator is determined so that the voltage compensator compensates for the difference in the output current command current. Considering this, since the output timing of the voltage command to the electric motor is 1/2 of the period of current control, that is, 1/4 of the carrier period T, the gain ratio k is obtained as 1/2. = 1/2 is processed.
Since processing is performed in this manner, the present invention can be implemented even if sampling of the command current after a predetermined time Δt from the peak of the triangular wave carrier is omitted.

FIG. 6 is a block diagram showing another embodiment of the present invention. FIG. 6 differs from FIG. 1 in that adders 17A and 17B, a second q-axis voltage compensator 18, and a second d-axis voltage compensator 19 are added, and the current sampling timing generator is changed from 6 to 6 ′. In addition, the sample and hold device (1) is changed from 8 to 8 '.
The current sampling timing generator 6 ′ outputs the sample signal 21A ′ as a sample signal 21A ′ so that the sample signal 21A is output after a predetermined time Δt in addition to the peak of the triangular wave carrier (both peaks and valleys of the triangle wave) of the sample signal 21A. Therefore, the sample signals 21A ′ and 21B are output at the same timing.
The sample-and-hold device (1) 8 ′ uses this sample signal 21A ′ to give calculation timings to the three-phase to two-phase converter 9, the second q-axis voltage compensator 18, and the second d-axis voltage compensator 19. The amount of change in the q-axis output current Iq_fb and the d-axis output current Id_fb, which are the outputs of the three-phase to two-phase converter 9, is used, and the dead time caused by reading the output current (the voltage command is (Time until timing of output to the motor) is compensated.

The second q-axis voltage compensator 18 and the second d-axis voltage compensator 19 calculate the voltage compensation value, send the compensation amount to the adders 17A and 17B, and the q-axis voltage command Vq *, d-axis. Add to voltage command Vd *. The calculation method in the second q-axis voltage compensator 18 and the second d-axis voltage compensator 19 is only the difference between the command current and the detection current, and the q-axis voltage compensator 10 and the d-axis voltage compensator. Since the processing is the same as 11, the description is omitted here.
If necessary, a filter is added to the input or output of the second q-axis voltage compensator 18 and the second d-axis voltage compensator 19 so as to remove ripples and the like depending on the carrier on the output current waveform. It may be. In this case, it is desirable to add a filter having a response frequency that attenuates the carrier frequency component but does not deteriorate the current response.
Since processing is performed in this manner, a delay from when the output current is sampled until the command voltage is actually supplied to the motor can be compensated.

In the above description, the sample signals 21A or 21A ′ and 21B are output at the peak of the triangular wave carrier (both the peak and the valley of the triangular wave), but the operation of the current controller and the output of the voltage command to the motor. However, even if the configuration is performed at the timing of one of the peak and valley of the triangular wave, the equation for calculating the proportional gain k differs, but it goes without saying that the present invention can be implemented.
In the above description, the carrier signal is a triangular wave carrier. However, any carrier signal having periodicity such as a sawtooth wave may be used.
Further, some of the configurations shown in FIGS. 1, 4 and 6 described above may be used in combination.

1 is a block diagram showing the configuration of an electric motor control device according to an embodiment of the present invention. The timing chart which shows the processing timing of the motor control apparatus by this invention Timing chart explaining gain ratio k of the present invention Block diagram of q-axis voltage compensator 12 ′ and d-axis voltage compensator 13 ′ showing the configuration of an electric motor control device showing another embodiment of the present invention. Timing chart showing another embodiment of the present invention Configuration block diagram of an electric motor control device showing another embodiment of the present invention Block diagram showing the configuration of current control of a conventional motor

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Electric motor 2 Inverter 3 PWM pulse generator 4 Triangular wave carrier generator 5 Two-phase three-phase converter 6, 6 'Current sampling timing generator 7A, 7B Current detector 8, 8' Sample hold device (1)
9 3-phase 2-phase converter 10 q-axis current controller 11 d-axis current controller 12, 12 ′ q-axis voltage compensator 12A delay circuit 12B subtractor 12C compensator 12D, 12E, 12F coefficient multiplier 12G multiplier 12H, 12I Adder 13, 13 'd-axis voltage compensator 13A delay circuit 13B, 13I subtractor 13C compensator 13D, 13E, 13F coefficient multiplier 13G multiplier 13H adder 14A sample and hold device (2)
14B Sample-and-hold device (3)
15A, 15B Subtractors 16A, 16B, 17A, 17B Adder 18 Second q-axis voltage compensator 19 Second d-axis voltage compensator 20 Synchronization signal
21A, 21A ′, 21B Sample signal 101 Control device 102 Power converter 103 Load device 104 Current detector 105 Command value generator 111 Sample signal 112 for sampling current detection value Sample / hold device for sampling current detection value ( 1)
113 Sample signal for sampling current command value 114 Sample and hold device for sampling current command value (2)
115 Sample signal generator 116 Voltage command calculator 117 PWM controller 118 Synchronization signal 271 Comparator 272 Triangular wave generator

Claims (9)

A first sample-and-hold device that samples and detects an output current flowing through the motor at a timing synchronized with a carrier signal, a current controller that controls the command current and the output current to match, and a current controller A motor control comprising a PWM pulse generator that compares a voltage command calculated using an output with the carrier signal and converts the voltage command into a PWM pulse, and a power converter that supplies power to the motor using the PWM pulse. In the device
A second sample and hold device that samples the command current at a timing synchronized with the carrier signal;
The second sample and hold unit is configured to sample the command current after a predetermined time Δt from the timing synchronized with the carrier signal,
A voltage compensator for calculating a voltage compensation amount based on an output of the second sample and hold unit;
An electric motor control device comprising: an adder that adds the output of the voltage compensator to the voltage command to obtain a new voltage command.   The motor controller according to claim 1, wherein the current controller and the voltage compensator are configured by proportional / integral control, and a ratio between two proportional gains and an integral gain is equal.   3. The motor control device according to claim 2, wherein a ratio between the proportional gain of the current controller and the proportional gain of the voltage compensator is obtained by calculation from a relationship between a cycle of the carrier signal and the predetermined time Δt.   The motor control device according to claim 1, wherein the timing of sampling the output current is both or one of peak values (peaks or valleys) of the carrier signal.   The motor control device according to claim 1, wherein a timing at which the PWM pulse reflecting the new voltage command is supplied to the motor is immediately after the calculation of the new voltage command. The voltage compensator includes a delay circuit that holds the command current detected in the previous sampling, a subtractor that calculates a difference between the command current detected by sampling after a predetermined time Δt and the output of the delay circuit, and the subtraction A multiplier that multiplies the output of the generator by a predetermined gain determined by a motor constant without using proportional / integral control;
The motor control device according to claim 1, further comprising an adder that adds an output of the multiplier to an input value of the current controller. The voltage compensator includes a delay circuit that holds the command current detected in the previous sampling;
A subtractor for calculating a difference between the command current detected in the current sampling and the output of the delay circuit;
A multiplier for multiplying the output of the subtractor by a predetermined gain;
The motor control device according to claim 1, further comprising an adder that is proportionally / integrally controlled to add the output of the multiplier to an input value of the current controller. A first sample-and-hold device that samples an output current flowing through the motor at a timing synchronized with a carrier signal and detects the output current; a current controller that controls the command current and the output current to match; and the current A PWM pulse generator that compares a voltage command calculated using the output of the controller with the carrier signal and converts the voltage command into a PWM pulse, and a power converter that supplies power to the motor using the PWM pulse. In the motor control device
A second sample and hold device that samples the command current at a timing synchronized with the carrier signal;
The first and second sample and hold devices are configured to sample the command current and the output current even after a predetermined time Δt from the timing synchronized with the carrier signal,
A first voltage compensator for calculating a compensation amount based on the output of the first sample and hold unit at the predetermined time Δt;
A second voltage compensator for calculating a compensation amount based on the output of the second sample and hold unit at the predetermined time Δt;
An electric motor control device comprising: an adder that adds the outputs of the first and second voltage compensators to the voltage command to obtain a new voltage command. A sample-and-hold device that samples the command current at a timing synchronized with the carrier signal, a current controller that controls the command current and the output current to match, and a voltage command calculated using the output of the current controller In a control method of an electric motor control device comprising: a PWM pulse generator that converts a PWM pulse by comparing with a carrier signal; and a power converter that supplies electric power to the electric motor using the PWM pulse.
Sampling the command current at a timing synchronized with the carrier signal,
Further, the command current is sampled after a predetermined time Δt,
A voltage compensation amount is calculated based on the two command currents sampled during a predetermined time Δt,
A control method for an electric motor control device, wherein the voltage compensation amount is added to the voltage command to make a new voltage command.