JP5334803B2 - Motor simulator - Google Patents

Description

  The present invention relates to an apparatus for testing an inverter that drives a motor, and more particularly to a motor simulation apparatus that is connected instead of a motor as a load of the inverter and simulates the motor.

  In order to test an inverter having a motor as a load, a motor simulation device connected in place of the motor as a load of the inverter has been developed (see, for example, Patent Document 1). This motor simulation device can simulate a motor with any characteristics in any state by simply setting the parameters of the motor to be simulated, so testing in various operating states of the inverter is possible with simple operation It becomes.

An example of a prior art of a motor simulation device that simulates a permanent magnet synchronous motor is shown in FIG. 4, and the prior art will be described based on this figure.
The output of the motor simulation device 9 is connected to the output of the inverter under test 2 via the terminal block 7. In the motor simulation device 9, the output of the inverter 1 is connected to the terminal block 7 through the filter 81, the transformer 82, and the reactor 3 and output. The output of the current detector 51 that detects the current of the reactor 3 is input to the voltage command generator 621. The motor parameter setter 623 includes R, Ld, Lq, φ (R: winding resistance of the simulated motor, Ld, Lq: inductance of each axis of the simulated motor, φ: permanent magnet of the simulated motor, in advance. The parameters of the motor to be simulated such as the armature flux linkage) are set.
The voltage command generator 621 uses the motor parameter output from the motor parameter setter 623 and the inductance L2 of the reactor 3, and the rotation that is the voltage component of the d axis and the q axis orthogonal to the d axis by the following expressions 1 and 2. The voltage commands vcdr and vcqr on the coordinates are obtained and output. In addition, the following formulas 1 and 2 are formulas derived from formula 3 to formula 6 as will be described later.

vcdr = R · id−ω · iq · (Lq−L2) Equation 1
vcqr = R · iq + ω · id · (Ld−L2) + ω · φ Equation 2

Here, R is the winding resistance of the simulated motor, Ld and Lq are the inductances of each axis of the simulated motor, φ is the armature linkage magnetic flux by the permanent magnet of the simulated motor, and these are This is the output of the motor parameter setting unit 623.
Also, ω is the motor electrical angular frequency that is the output of the motor rotational speed calculator 616, id and iq are ia and ib that are obtained by converting the current of the output of the current detector 51 into two axes, and rotational coordinates are converted by θ, d This is the current component of the axis and the q axis orthogonal to the axis.
Θ is the output of the d-axis phase calculator 611 that integrates the output ω of the motor rotation speed calculator 616 with time.
The above θ and the voltage commands vcdr and vcqr output from the voltage command generator 621 are given to the voltage controller 620. Further, the voltage at the connection point between the reactor 3 and the transformer 82 detected by the voltage detector 53 is converted into two axes, and the voltages vca and vcb converted into the two axes are given to the voltage controller 620, and the voltage controller 620 Is controlled so that the voltage at the connection point between the reactor 3 and the transformer 82 becomes the voltage commands vcdr and vcqr expressed by Equations 1 and 2.

The above formulas 1 and 2 are obtained as follows.
Equations 3 and 4 which are characteristic equations of the motor on the rotational coordinates are shown below.

vd = R · id + Ld · p (id) −ω · Lq · iq Equation 3
vq = R · iq + Lq · p (iq) + ω · Ld · id + ω · φ Equation 4

Here, R, Ld, and Lq are the winding resistance of the simulated motor and the inductance of each axis of the simulated motor, φ is the armature flux linkage by the permanent magnet of the simulated motor, and ω is the motor electrical The angular frequency, id, iq is a current obtained by rotating the currents ia, ib converted into the two axes and rotating coordinates with θ. Further, P () means time differentiation within (), and vd and vq are values obtained by rotating the voltage of the terminal block 7 with θ.
Further, Formulas 5 and 6 which are characteristic formulas of the reactor 3 are shown below.

vd = R2 · id−ω · L2 · iq + L2 · p (id) + vcd Equation 5
vq = R2 · iq + ω · L2 · id + L2 · p (iq) + vcq Equation 6

  Here, R2 is the resistance of the reactor 3, and vcd and vcq are rotation coordinates of the voltage on the transformer 82 side of the reactor 3 by θ.

Formula 1 is derived by substituting Formula 5 for vd in Formula 3, ignoring the term of P (), which is a time derivative term, R2 = 0, and rewriting vcd as vcdr. 2 is derived in the same manner by substituting Equation 6 into vq of Equation 4.
That is, the voltages vcdr and vcqr calculated by the equations 1 and 2 indicate the voltage at the connection point between the reactor 3 and the transformer 82, which is derived from the motor characteristic equation and the reactor 3 characteristic equation. By controlling the voltage at the connection point of the reactor 3 and the transformer 82 to be the values shown in Equations 1 and 2 by 620, the characteristics of the motor simulator 9 viewed from the inverter under test 2 should be simulated. The characteristics can be the same as when the motor is connected.

In the voltage controller 620, as shown in FIG. 5, in the rotation coordinate converter 620a, the voltages vca and vcb are subjected to rotation coordinate conversion by θ to obtain voltages vcd and vcq. The deviations of the voltages vca and vcb and the voltage commands vcdr and vcqr are amplified by, for example, PID calculation so that the voltages vcd and vcq follow the voltage commands vcdr and vcqr, respectively. Find vidr and viqr.
The voltage commands vidr and viqr are reversely rotated and converted into stationary coordinates by the reverse rotation coordinate converter 620b, and are output to the inverter 1 as voltage commands viar and vibr.
The inverter 1 outputs a voltage corresponding to the voltage commands via and vibr output from the voltage controller 620 to the filter 81, and the output of the filter 81 is output from the terminal block 7 via the transformer 82 and the reactor 3.
As described above, when the terminal block 7 is viewed from the inverter 2 to be tested, it is regarded as equivalent to a simulated motor connected to the terminal block 7.

JP 2003-153547 A

In the prior art shown in FIG. 4, considering the case where, for example, vd which is the voltage of the terminal block 7 is suddenly changed by ΔV by the inverter under test 2, the current flowing in the simulated motor is ΔV / Ld (Ld: simulated motor). However, the current flowing through the reactor 3 of the simulation apparatus changes only with the inclination of ΔV / L2 (L2: inductance of the reactor 3).
Therefore, if the values of L2 and Ld are different, the simulation apparatus cannot simulate the simulated motor in a transient state. For this reason, the inductance L2 of the reactor 3 of the prior art must be a value substantially equal to the inductance Ld or Lq of the motor to be simulated, and if the value of Ld or Lq set in the motor parameter setting unit 623 is changed Reactor 3 needs to be replaced.
Further, since the values of Ld and Lq may have values that are greatly different depending on the motor to be simulated, it may not be possible to select an inductance L2 that is substantially equal to both.

The inductance of the reactor 3 changes according to the magnitude of the current that flows due to magnetic saturation, but if only the representative value is used in the calculation of Equation 1 and Equation 2, the actual inductance of the reactor 3 cannot be reflected. Therefore, the simulation apparatus of the prior art cannot accurately simulate the motor to be simulated even in a steady state.
The present invention has been made in view of the above circumstances, can accurately simulate a motor, and can quickly change the voltage fluctuation even in a transient state such as when the output voltage of the inverter under test is suddenly changed. It is an object of the present invention to provide a motor simulation device that can detect and reflect it in a voltage command.

In the present invention, as shown in FIG. 1, a filter voltage generator 622 is provided in place of the voltage command generator 620, and the motor simulation device is used in a transient state such as when the voltage output from the inverter under test 2 is suddenly changed. The output of the motor input voltage detector 52 that detects the voltage at the input terminal 7 is input to the filter voltage command generator 620. Thereby, the filter voltage command generator 620 can quickly detect the voltage fluctuation and reflect it in the voltage command.
For example, consider a case where vd changes suddenly by ΔV.
In that case, the current flowing through the simulated motor changes with a slope of ΔV / Ld. In order to change the current flowing through the reactor 3 of the simulator with the same inclination, the filter voltage command may be changed abruptly by ΔVc in response to the change in ΔV. Then, the slope of the current flowing through the reactor 3 becomes (ΔV−ΔVc) / L2, and in order to coincide with the slope ΔV / Ld of the current flowing through the simulated motor, ΔVc = ΔV · (1−L2 / Ld) It will be good.
Therefore, even if the inductance L2 of the reactor 3 and the Ld and Lq, which are parameters of the motor to be simulated, are greatly different values, the motor can be accurately simulated in a transient state.
Even if the following formulas A and B derived from the formulas 3 to 6 without ignoring the current differential terms are used instead of the formulas 1 and 2 for obtaining the voltage command of the prior art, the current detection is performed. Simulations reveal that the simulation accuracy of the transient state is improved due to the detection delay of the detector 51 and the voltage control delay of the voltage controller 620, but the improvement effect is low.

vcdr = (R−R2) · id−ω · (Lq−L2) · iq + (Ld−L2) · p (id) Expression A
vcqr = (R-R2) .iq + .omega. (Ld-L2) .id + (Lq-L2) .p (iq) +. omega..phi.

For example, when p (id)> 0 and L2> Ld, vcd needs to change in a negative direction stepwise, but the change is delayed due to the control delay.
Then, p (id) becomes smaller due to L2> Ld, the change of vcdr in the negative direction becomes smaller, and the change of vcd in the negative direction becomes slower and p (id) becomes increasingly smaller. Thus, the effect of improving the simulation accuracy in the transient state is reduced.
In the present invention, by using the output of the motor input voltage detector instead of the current differentiation, this vicious circle can be interrupted, and the simulation accuracy of the transient state depends only on the control delay, which is greatly improved.

Based on the above, the present invention solves the above problems as follows.
(1) An inverter that outputs a voltage according to the input voltage command, a filter that smoothes the output voltage of the inverter, and a reactor that is connected between the filter and a motor simulator input terminal to which the inverter under test is connected A filter voltage command generator that outputs a filter voltage command that is a voltage command smoothed by the filter; and a voltage command that causes the smoothed voltage of the filter to follow the filter voltage command. Current detector that detects the current of the reactor in a motor simulator that is configured to be equivalent to a motor that simulates the characteristics of the inverter viewed from the motor simulator input terminal. a vessel, a motor input voltage detector for detecting a voltage of said motor simulator input terminal, smoothing the filter A voltage detector for detecting a voltage, provided the inductance storage unit for storing the inductance of the reactor.
The filter voltage command generator receives the output of the current detector and the output of the motor input voltage detector , and in accordance with the output of the current detector, the inductance of the reactor stored in the inductance storage device And the filter voltage command is obtained based on the electric characteristic equation of the simulated motor using the inductance and resistance value of the reactor, the output of the current detector, and the output of the motor input voltage detector.
The voltage controller controls the inverter so that a voltage detected by a voltage detector that detects a smoothed voltage of the filter becomes the filter voltage command.
( 2 ) In the above ( 1 ), an inductance calculator that measures the inductance of the reactor according to the magnitude of the current flowing through the reactor is provided, and the inductance calculator output is stored in the inductance memory.

In the present invention, the following effects can be obtained.
(1) In a transient state such as when the voltage output from the inverter under test 2 is suddenly changed, the voltage fluctuation is detected quickly and reflected in the voltage command in the filter voltage command generator. Even if the inductance L2 of the reactor connected between the filter for smoothing the output voltage of the motor and the input terminal of the motor simulator and the Ld and Lq which are the parameters of the motor to be simulated are greatly different from each other, It becomes possible to simulate a motor.
(2) An inductance storage device that stores the inductance of the reactor according to the current value is provided, and the inductance value stored in the inductance storage device is selected and output according to the current value. The inductance value can be reflected in the voltage command calculation, and the motor can be accurately simulated even if the inductance of the reactor changes due to magnetic saturation or the like.
(3) In order to store the inductance value according to the current value in the inductance memory, it is necessary to measure and store the inductance according to the current in the inductance memory. In the present invention, since the function of measuring the inductance is added to the simulation device, the inductance of the reactor can be easily measured and stored.

It is a figure which shows the motor simulation apparatus of the Example of this invention. It is a figure which shows the calculation block of a filter voltage command generator. It is explanatory drawing which shows the function which measures and memorize | stores an inductance. It is a figure which shows the conventional motor simulation apparatus. It is a figure which shows the control block of a voltage controller.

Embodiments of the present invention will be described below.
FIG. 1 is a diagram in which an inverter under test is connected to the motor simulation device of one embodiment of the present invention, and the following will be described with reference to this figure.
In the motor simulation device 9 shown in FIG. 1, the output of the inverter 1 is connected to the motor simulation device input terminal 7 via the filter 81 and the reactor 3, and the output of the inverter under test 2 is connected to the motor simulation device input terminal 7. It is connected. The motor simulation device 9 operates so that the characteristics of the motor simulation device 9 viewed from the motor simulation device input terminal 7 are equivalent to those of the simulation motor.

The operation principle of the motor simulation device according to the embodiment of the present invention will be described below.
The filter 81 includes a filter reactor L1 and a filter capacitor C, and the voltage detector 53 detects the voltage of the filter capacitor C, converts it into biaxial vca and vcb, and outputs it.
The motor rotation speed calculator 616 calculates the motor electrical angular angular frequency ω, and the d-axis phase calculator 611 integrates ω with time to determine the d-axis phase θ.
The motor parameter setter 623 includes R, Ld, Lq, and φ (R: winding resistance of the simulated motor, Ld, Lq: inductance of each axis of the simulated motor, φ: simulated) Armature interlinkage magnetic flux by a permanent magnet of the motor to be set in advance by the user.
The current detector 51 detects the current of the reactor 3, converts it into biaxial ia and ib, and outputs it. The inductance storage device 630 stores the inductance L2 of the reactor 3 according to the magnitude of the current flowing through the reactor 3, and outputs L2 according to the current value of the output of the current detector 51.
The motor input voltage detector 52 detects the voltage of the input terminal block 7 of the motor simulator 9 that is the output voltage of the inverter 2 to be tested, converts it into two-axis va and vb, and outputs the result.

The filter voltage command generator 622 outputs the motor rotation speed calculator 616 output ω, the d-axis phase calculator 611 output θ, the motor parameter setter 623 output R, Ld, Lq, φ, and the inductance storage 630 output. L2 of the current detector 51, ia and ib of the output of the current detector 51, and va and vb of the output of the motor input voltage detector 52, etc. are input to obtain the voltage commands vcdr and vcqr of the filter capacitor as will be described later, and the voltage controller 620 Output to.
The voltage controller 620 receives vca and vcb output from the voltage detector 53, the phase θ output from the d-axis phase calculator 611, and the filter capacitor voltage commands vcdr and vcqr output from the filter voltage command generator 622. Then, the voltage controller 620 controls the inverter 1 so that the voltage of the filter capacitor C of the filter 81 becomes the voltage commands vcdr and vcqr.

That is, as shown in FIG. 5, the voltage controller obtains voltages vcd and vcq by rotating the voltages vca and vcb with θ in the rotation coordinate converter 620a to obtain the voltages vcd and vcq. The deviation of the voltage commands vcdr and vcqr is amplified by, for example, PID calculation, voltage commands vidr and viqr on the rotation coordinates are obtained, and the voltage commands vidr and viqr are subjected to reverse rotation coordinate conversion by the reverse rotation coordinate converter 620b to obtain a voltage. It outputs to the inverter 1 as commands via and vibr.
As described above, the inverter 1 outputs a voltage corresponding to the voltage commands via and vibr output from the voltage controller 620 to the filter 81, and the output of the filter 81 is output from the terminal block 7 through the reactor 3.

Hereinafter, the process in the filter voltage generator 622 will be described.
As described above, the filter voltage command generator 622 outputs ω of the motor rotational speed calculator 616, θ of the d-axis phase calculator 611, and R, Ld, Lq, φ (R of the motor parameter setter 623 output. : Winding resistance of simulated motor, Ld, Lq: inductance of each axis of simulated motor, φ: armature interlinkage magnetic flux by permanent magnet of simulated motor, and L2 (reactor 3 output) of inductance storage 630 Inductance), ia and ib of the current detector 51 output, va and vb of the motor input voltage detector 52 output, and R2 (the resistance of the reactor 3), The filter capacitor voltage commands vcdr and vcqr are obtained. Here, id, iq and vd, vq are rotation coordinates of ia, ib, va, vb, respectively, with d-axis phase θ.

vcdr = vd−L2 / Ld · vd + (R · L2 / Ld−R2) · id−ω · (Lq · L2 / Ld−L2) · iq Equation 7
vcqr = vq−L2 / Lq · vq + (R · L2 / Lq−R2) · iq + ω · (Ld · L2 / Lq−L2) · id + ω · φ · L2 / Lq Equation 8

  Equation 7 is obtained by solving Equation 3 with p (id), substituting it into Equation 5, solving it with vcd, and rewriting vcd as vcdr. Equation 8 is derived similarly from Equation 4 and Equation 6. That is, when the equations 3 and 4 are solved with p (id), the following equations C and D are obtained.

pid = (vd−R · id + ω · Lq · iq) / Ld Formula C
piq = (vq−R · iq−ω · Ld · id−ω · φ) / Lq Equation D

  By substituting the pid of the formula C and the piq of the formula D into the formulas 5 and 6 and solving with vcd and vcq, and replacing the vcd and vcq with vcdr and vcqr, respectively, the formulas 7 and 8 Is obtained.

FIG. 2 is a block diagram showing a configuration example when the processing in the filter voltage generator 622 is realized by hardware.
In the figure, M1 to M14 are multipliers, D1 to D2 are dividers, A1 to A7 are adders / subtractors, 622a is a rotary coordinate converter that obtains voltages vd and vq by rotating the voltages va and vb with θ. A rotational coordinate converter 622b obtains currents id and iq by performing rotational coordinate conversion of the currents ia and ib with θ.
In this figure, L2 and Ld are input to a divider D1, L2 / Ld is calculated, and Id output from L2 / Ld, R, R2, and the rotating coordinate converter 622b is multiplied by multipliers M1 and M2 and an adder / subtractor A1. The term (R · L2 / Ld−R2) · id of Equation 7 is obtained, and the above L2 / Ld and vd output from the rotary coordinate converter 622a are computed by the multiplier M5 and the adder / subtractor A4. The term vd−L2 / Ld · vd in Equation 7 is obtained.
Further, L2 / Ld and Lq, ω, and L2 are calculated by the multiplier M7 and the adder / subtractor A5, and the result is multiplied by iq and ω output from the rotary coordinate converter 622b by the multipliers M8 and M9. 7 of ω · (Lq · L2 / Ld−L2) · iq is obtained, and these are added / subtracted by the adder / subtractor A3 to output the voltage command vcdr.

Further, L2 / Lq is input to the divider D2 to calculate L2 / Lq, L2 / Lq and vq output from the rotating coordinate converter 622a are calculated by the multiplier M6, and L2 / Lq · vq in Equation 8 is calculated. Is obtained,
The above L2 / Lq, Ld and L2 are calculated by the multiplier M10 and the adder / subtractor A6, and the result and id and ω output from the rotary coordinate converter 622b are calculated by the multipliers M11 and M12 to obtain ω · The term of (Ld · L2 / Lq−L2) · id is calculated, and further, ω, φ, and L2 / Lq are calculated by the multipliers M13 and M14, and the term of ω · φ · L2 / Lq in Equation 8 is calculated. These are obtained, and vq output from the rotary coordinate converter 622a is added / subtracted by the adder / subtractor A7, and the voltage command vcqr is output.
As described above, in this embodiment, the va and vb of the motor input voltage detector 52 are input to the filter voltage command generator 622, and the voltages va and vb are rotationally coordinate-transformed by θ to obtain the voltages vd and vq. As a result, fluctuations in vd and vq are reflected in the voltage commands vcdr and vcqr as vd (1-L2 / Ld) and vq (1-L2 / Lq), respectively, so that the slope of the current flowing through the reactor 3 is simulated. The slope of the current flowing through the motor can be matched.
For this reason, as described above, even if the inductance L2 of the reactor 3 and the parameters Ld and Lq of the motor to be simulated are greatly different values, the motor can be accurately simulated in the transient state.

In order to perform the above calculation in the filter voltage generator 622, the inductance L2 of the reactor 3 corresponding to the magnitude of the current flowing through the reactor 3 needs to be stored in the inductance memory 630.
Therefore, the motor simulation device may be provided with a function of measuring the inductance of the reactor 3 and storing the inductance measured thereby in the inductance memory 630.

FIG. 3 is a diagram illustrating the function of measuring the inductance described above.
In FIG. 3, when measuring the inductance, all terminals of the motor simulation device input terminal 7 are short-circuited. Further, an L2 current controller 631 is used instead of the voltage controller 620, and the inverter 1 is controlled by voltage commands via and vibr output from the L2 current controller 631.
The L2 current controller 631 outputs voltage commands via and vibr that are input to the inverter 1 so that ia and ib of the current detector 51 output are alternating current with a predetermined angular frequency ω0 and a predetermined amplitude. The predetermined amplitude is a plurality of various amplitudes.
The inductance calculator 632 receives the current detector 51 output ia and ib and the voltage detector 53 output vca and vcb, converts them into γδ coordinates that rotate at a predetermined angular frequency ω0, and converts them to iγ and iδ. vcγ and vcδ are obtained, and the following equations 9 and 10 are calculated to obtain and output the inductance L2 at the current square value I2 of the reactor 3.

I2 = ia · ia + ib · ib Equation 9
L2 = (vcγ · iδ−vcδ · iγ) / (ω0 · I2) Equation 10

  The inductance storage device 630 obtains the current square value I2 of the reactor 3 from Expression ia and ib of the current detector 51 output according to Expression 9, and the inductance L2 obtained by the inductance calculator 632 is stored in a storage location corresponding to I2. Remember.

  According to the present invention, a motor simulation device capable of accurately simulating a motor is obtained even in a transient state where the voltage of the output of the inverter under test changes suddenly, or even when the inductance of the reactor changes according to the current flowing through it due to magnetic saturation or the like. be able to.

DESCRIPTION OF SYMBOLS 1 Inverter 2 Inverter under test 3 Reactor 51 Current detector 52 Motor input voltage detector 53 Voltage detector 611 d-axis phase calculator 616 Motor rotation speed calculator 621 Voltage command generator 622 Filter voltage command generator 620 Voltage controller 623 Motor parameter memory 630 Inductance memory 631 L2 current controller 632 Inductance calculator 7 Motor simulator input terminal 81 Filter 82 Transformer 9 Motor simulator

Claims (2)

An inverter that outputs a voltage in accordance with the input voltage command; a filter that smoothes the output voltage of the inverter; the filter; a reactor connected between motor simulation device input terminals to which the inverter under test is connected ; A filter voltage command generator that outputs a filter voltage command that is a voltage command smoothed by the filter, and a voltage command that causes the smoothed voltage of the filter to follow the filter voltage command is output to the inverter. A motor simulator that is configured with a voltage controller and operates so as to be equivalent to a motor that simulates the characteristics of the inverter viewed from the motor simulator input terminal,
A current detector for detecting the current of the reactor; a motor input voltage detector for detecting a voltage of the motor simulation device input terminal; a voltage detector for detecting a smoothed voltage of the filter; and an inductance of the reactor An inductance storage device for storing
The filter voltage command generator receives the output of the current detector and the output of the motor input voltage detector , and in accordance with the output of the current detector, the inductance of the reactor stored in the inductance storage device Using the inductance and resistance value of the reactor and the output of the current detector and the output of the motor input voltage detector, the filter voltage command is obtained based on the electric characteristic equation of the simulated motor ,
The motor, wherein the voltage controller controls the inverter so that a voltage detected by a voltage detector that detects a smoothed voltage of the filter becomes the filter voltage command. Simulating device. An inductance calculator that measures the inductance of the reactor according to the magnitude of the current flowing through the reactor;
The motor simulation device according to claim 1 , wherein the inductance calculator output is stored in the inductance storage device.

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