WO1998042067A1

WO1998042067A1 - Power converter, ac motor controller and their control method

Info

Publication number: WO1998042067A1
Application number: PCT/JP1997/000909
Authority: WO
Inventors: Hironori Ohashi; Makoto Takase; Hiroyuki Tomita; Seiji Ishida; Masaki Sugiura
Original assignee: Hitachi, Ltd.
Priority date: 1997-03-19
Filing date: 1997-03-19
Publication date: 1998-09-24
Also published as: JP3329831B2

Abstract

An automatic on-delay compensation value regulator, and a low cost and high precision controller are provided. An on-delay compensation value calculator (35) is provided in a control circuit (3). The current of an AC motor (1) and the voltage of a power converter (2) are measured, and the carrier frequency is varied to calculate an on-delay compensation value. A Fourier converter is built in the on-delay compensation value calculator (35). The on-delay compensation value is varied so as to minimize the harmonics and ripples in the current to obtain a proper on-delay compensation value. As the deviation of the on-delay compensation value which is caused by the variation of the power converter itself can be controlled automatically, a torque ripple caused by the variation of the on-delay compensation value is prevented and a high precision controller is realized. Further, as the allowance of the variation of the hardware is increased, a low cost controller is realized.

Description

Details

TECHNICAL FIELD The present invention relates to a power conversion device, an AC motor control device, and a control method thereof.

The present invention relates to an AC motor control device that drives an AC motor using a power converter using a switching element.

In addition, the present invention is applicable to all control devices using a power converter using a switching element, and can be used, for example, in a power converter such as a PWM converter. Background art

For convenience of explanation, the following description uses a motor as an example of the load of the power converter.

A three-phase power converter 2 shown in FIG. 12 is generally used as a control device for converting the power to a variable frequency power supply using a switching element and controlling the speed of the AC motor 1. In FIG. 12, reference numeral 3 denotes a control circuit, and CT denotes a current detector for detecting an output current. This power converter is characterized in that the upper and lower arms of the switching element are connected in series to a so-called three-phase bridge for each output phase, and are exclusively switched. Since a semiconductor switching element such as an IGBT is used as the switching element and the ON / OFF operation has a delay, the ON signal of the other switching signal is delayed with respect to the OFF signal of one of the upper and lower arms of each phase. If switching is not performed with an on-delay period, the switching elements in the upper and lower arms will cause an arm short, and the switching elements will be destroyed. For this reason, the control circuit 3 receives the voltage command V * from the control arithmetic unit 31 such as the motor current and outputs the PWM pattern. An on-delay generator 34, which outputs the signal to the generator 3 and delays the on-signal only while the switching element is off, is required.

When viewed from a control device such as a motor, the on-delay is non-linear with respect to the direction of the output current and the like, and as shown in FIG. 10, the output current (an example of the line current iu is shown. (The same applies to iv and iw), which degrades control characteristics and causes torque ripple and other factors. (Fig. 10 shows the output current fundamental wave Y1 and the fifth harmonic wave Y5 at the top. The middle stage shows the distorted output current iu, and the lower stage shows the id obtained by d-q conversion of the current and DC display as described later). For this reason, recently, in addition to the on-delay generator 34, an on-delay compensator 33 shown in FIG. 12 is provided to eliminate the influence of the on-delay. The on-delay compensator 33 considers the direction (polarity sgn (i)) of the output current i (iu, iv, iw) during the on-time T on of the signal input from the PWM pattern generator 32. The ray compensation value Td is added to compensate for the on-delay component as follows.

T 'on—T on + sgru i)

However, this on-delay compensation value T d is the time from when an ON signal is input to the switching element to when it is actually turned on, t on, and the time from when an off signal is input to when it is actually turned off is t off. The time during which the signals input from the PWM pattern generator 32 to the switching elements of the upper and lower arms are simultaneously off is defined as the on-delay time T dead

T d = T dead + t on-t off (1)

Becomes The times T dead, t on, and t off vary depending on the individual characteristics of hardware such as switching elements and control circuit components, so that T d also varies. Therefore, even if the on-delay compensation value T d is set to a specific value and the on-delay compensation is performed, compensation can be performed by the amount that T d varies. I can't.

As described above, the Td varies for each power converter due to the hardware, so the current is distorted when viewed as a motor control device, and the above-mentioned on-delay generator 34 and on-delay compensator 33 are still insufficient. Generates torque ripple. In order to prevent this as much as possible, conventionally, it was necessary to use a selected product for the hardware (such as a photo bra) for each term in equation (1) or manually adjust the power converter individually.

An object of the present invention is to provide an inexpensive control device in which a control device automatically adjusts an on-delay compensation value Td. The second object is to provide a highly accurate control device by suppressing torque ripple and the like of the control device by this automatic adjustment. Disclosure of the invention

For the first and second purposes, an on-delay compensation value calculator 35 that automatically inputs the current and voltage and adjusts the on-delay compensation value Td is provided. On-delay compensation value calculation is started by the calculation start signal.

The on-delay compensation value calculator 35 detects the current and the voltage, extracts the characteristic amount such as the current distortion by the on-delay compensation, and calculates the on-delay compensation value. BRIEF DESCRIPTION OF THE FIGURES

FIG. 1 is a control block diagram according to a first embodiment of the present invention.

FIG. 2 is a control flowchart of the first embodiment of the present invention.

FIG. 3 shows the relationship between the current controller and the carrier frequency for explaining the operation principle of the first embodiment of the present invention. FIG. 4 is a control block diagram according to a second embodiment of the present invention. Fig. 5 shows the current waveform when the on-delay is not compensated.

FIG. 6 shows a relationship between harmonics and an on-delay compensation value for explaining the operation principle of the second embodiment of the present invention.

FIG. 7 is an embodiment of a control port according to the second embodiment of the present invention.

FIG. 8 shows another embodiment of the control port according to the second embodiment of the present invention.

FIG. 9 is a control block diagram of the third embodiment of the present invention.

FIG. 10 is an example of a line current waveform when on-delay is not compensated.

FIG. 11 is a control flowchart of a third embodiment of the present invention. FIG. 12 is a control block diagram of a conventional control device.

Hereinafter, a first embodiment of the present invention will be described with reference to FIG. FIG. 1 shows a control block diagram of a device in which an AC motor 1 is driven by a power converter 2 and controlled by a control circuit 3. The control circuit 3 controls speed control, current control, ratio control between output voltage and output frequency (hereinafter referred to as VZf control), and so-called vector control in which the excitation component and torque component are separated by vector. Calculator 31 1, PWM pattern generator 32 for generating gate signals for power converter 2, on-delay compensator 33, on-delay generator 34, and on-delay compensation value calculator 3 according to the present invention 5a etc. CT is a current detector that detects an output current.

The control calculator 31 gives a voltage command V * to the PWM pattern generator 32. The PWM pattern generator 32 uses a well-known triangular wave comparison PWM or the like. The switching element of the power converter 2 (semiconductor such as IGBT) Switching The on time T on of the element is output. Thereby, DC power V dc is converted into AC power, and AC motor 1 is rotationally driven. Of course, the DC power supply V dc may be obtained by rectifying the AC.

As described above with reference to FIG. 12, in the present embodiment, as shown in FIG. 1, the power converter 2 connects the U-phase, V-phase, and W-phase switching elements in series with the upper and lower arms. And switch exclusively. Also, the on-delay generator 34 is provided to prevent a short circuit of the switching element. Furthermore, an on-delay compensator 33 is provided for suppressing current distortion.

In this embodiment, the variation in the on-delay compensation value Td, which cannot be compensated by the on-delay compensator 33, due to the hardware is automatically measured by the on-delay compensation value calculator 35a, and the variation is calculated by the hardware. The purpose is to provide a low-cost, high-precision control device that eliminates variations.

First, the operation of the on-delay compensation value calculator 35a of this embodiment will be described, and then the principle will be described. The on-delay compensation value calculator 35a of this embodiment starts operation in a flow chart as shown in FIG. 2 when an on-delay compensation value calculation start signal Std is given from outside the control device (STEP 100). ~ STEP103). In order to prevent the AC motor 1 from rotating, first, the on-delay compensation value calculator 35 a is supplied to the current controller 3 1 1 in the control calculator 31 so that a DC current flows between the u and V phases. The command I * is output, and the carrier frequency f 1 that determines the switching frequency of the switching element of the power converter 2 is output to the PWM pattern generator 32. The current controller 311 is, for example, a well-known PI (proportional-integral) controller, which is sufficient (STEP OOa).

Next, the on-delay compensation value calculator 35a observes that the current control output V * of the current controller 311 1 has become stable, and sets the current control output V * as a voltage command V between u and the V phase. (STEP OOb). Similarly, the carrier frequency The current is controlled with a frequency f 2 different from Equation 1 and a DC current command I * (STEP100c), and when the current control output V * is stabilized, the current control output V * is set to the u-V phase voltage command V 2 * _uv (STEP100d).

A series of such operations V - w phase-to-phase (STEP101), repeated wu phase-to-phase _{(STEP102), V uv, v} 2 * uv, V i * vw, v 2 * vw, vi * wu, v 2 * _{Get wu} . Then, the on-delay compensation value calculation is performed as shown in equations (2) to (4) (STEP 103).

= ^ν 1 κ ν- ^v 2 uv (2)

^ 2 _VW

¹ d vw (3

^V dci \

T _j = ^y i n- »One ^V 2 _WU (4)

d ^wu _ v _dc .

Here, V dc is the DC voltage of the power converter 2. These T duv, T dvw, and T dwu are used as the on-delay compensation values for each phase. In addition, it is expected that the processing will be complicated if each phase is individually set. In that case, it is clear that processing such as averaging may be performed as in Eq. (5) and compensation may be performed using T duvw for all three phases. It is.

One ^ duv * dvw + ^ dwu · · · · ^ ^

¹ duvw one ^ no

Next, the operation principle will be described. The on-delay compensation value T d is independent of the switching frequency of the switching element as shown in Eq. (1). However, if the operating cycle of the switching element (the reciprocal of the carrier frequency) becomes longer, the on-delay compensation value T d becomes a percentage And the effect of the on-delay compensation value Td is reduced, and the current waveform distortion is also reduced. Conversely, if the operation cycle of the switching element is shortened, the ratio of the switching element to the cycle is increased, and the effect is also increased. Therefore, the difference between the current control outputs V * in these two operation cycles can be used as the on-delay compensation value T d. Fig. 3 illustrates this relationship.

Fig. 3 shows the carrier frequency fc on the horizontal axis and the current control output V * on the vertical axis. Is taking. In the current control, the DC current command is set to the DC current command I * so that the output current becomes DC, so if the carrier f2 is selected at a low frequency, only the voltage drop RI * of the resistance R of the AC motor 1 is reduced. It is possible to extract the frequency current control output V * that appears as an effect of on-delay. On the other hand, if the carrier frequency is gradually increased to f1, the current control output V * is the sum of the voltage drop RI * and the on-delay voltage drop. Therefore, if this difference is taken, the voltage drop RI * cancels out and becomes the voltage of the on-delay voltage drop. The on-delay compensation value Td can be obtained by converting this to time at the frequency f1 as in Equations (2) to (4).

Therefore, in order to accurately obtain the on-delay compensation value T d, it is important to select f2 as the carrier frequency with a small on-delay effect and set f1 as the carrier frequency with a large on-delay effect. . If the switching element of power converter 2 is an IGBT, set f1 to 10 kHz or more and f2 to 5 kHz or less.In the case of bipolar drainage, set f1 to 2 kHz or more and f2 to 1 k. It is desirable to set it to Hz or less. In addition, in the present invention, since the on-delay compensation value Td is obtained by using a DC current, there is a possibility that the on-delay compensation value Td may be slightly deviated from the on-delay compensation value Td obtained by using an alternating current. It goes without saying that the obtained on-delay compensation value T d may be multiplied by a weighting factor.

In addition, as described above, as the DC current I *, t on and t off have different values depending on the current flowing through the switching element, as shown in equations (2) to (4), the DC current command I By changing * and performing the on-delay compensation value calculation as described above, it is possible to obtain a more accurate on-delay compensation value Td.

Next, a second embodiment of the present invention will be described. The difference from the first embodiment is that as shown in FIG. 1 is provided with an AC voltage generator 312, and the on-delay compensation value calculator 35b is provided with a Fourier transformer (high-speed FFT) or a Waltz converter for obtaining harmonics. The major difference is that the embodiment obtains the on-delay compensation value Td with direct current instead of the direct current. In order to keep the AC motor 1 from rotating, two-phase sinusoidal AC excitation is performed, and if on-delay compensation is removed, a current such as Y13 in Fig. 5 flows as the output current. This is due to the fact that the voltage drops near the zero current, but the current is distorted near the zero cross, even though a sinusoidal AC voltage is applied due to on-delay. By changing the on-delay compensation value Td so as to minimize this current distortion, the on-delay compensation value Td can be obtained.

Since the current waveform distorted by the on-delay (Y13 in Fig. 5) contains the third harmonic Y3 as shown in Fig. 5, this is calculated by the on-delay compensation value calculator 35b Find the third-order harmonic output A3 with a Fourier transformer (Fast FFT) or a Waltz converter inside, and find the on-delay compensation value Td so as to minimize A3 by the least square method. . Figure 6 illustrates this situation, where the horizontal axis is the on-delay compensation value T d and the vertical axis is the peak value A 3. From the relationship in Fig. 5, it is clear that A3 has a local minimum as shown in Fig. 6. For example, at first, starting from T d = 0 (point A) and gradually increasing T d (point → 8 → 点), at point D, A 3 increases. Here, we can reduce Td a little, and finally find the optimal on-delay compensation value at point E. These runs are exactly numerical analysis methods such as the least squares method, and can be easily realized by using these methods. FIG. 7 shows a flow chart of the second embodiment (STEP110 to STEP112). _C Excitation is first performed between u and v in the same manner as in the previous embodiment (STEP11 Oa). When the current waveform is stable, a Fourier transformer (high-speed FFT) A3 uv is taken out by means of an Orsh converter or the like (STEPl l Ob), and the on-delay compensation value T d uv that minimizes the A3 uv is determined by the least square method or the like (STEPl l Oc) . Similarly, between the V-w phases and between the w-u phases (STEP111, STEP112), the on-delay compensation values Tduv, Tdvw, and Tdwu are obtained.

In the above-described second embodiment, single-phase AC excitation is performed so as not to rotate the motor. However, if the AC motor 1 may be rotated, the on-delay compensation value may be adjusted using a flowchart as shown in FIG. Can be obtained (STEP120-STEP122). Here, what is different from the above is that the AC motor 1 is driven by V / f operation (STEP120), and the current waveform at this time is a waveform containing the fifth and seventh harmonics as shown in Fig. 10. That is. For this reason, at step 120a, at least one of A5 or A7 is extracted by a Fourier transformer (high-speed FFT) or a ゥ orsh converter, and driven by the least-squares method. Others are the same, and the description is omitted.

As described above, in the second embodiment, since the on-delay compensation T d can be obtained for each phase, the method of averaging and multiplying the weighting factor can be similarly performed as shown in the first embodiment. Needless to say. In addition, since the current and the like differ depending on the frequency and voltage value for exciting the AC motor 1, when determining the on-delay compensation T d more precisely, as shown in the first embodiment, the individual parameters ( It is clear that the voltage and frequency can be determined and obtained.

The third embodiment is a method in which the motor may be rotated as in the second method of the second embodiment described above.Since the AC motor 1 is actually rotated, more accurate on-delay compensation is performed. T d can be determined. The difference from the second embodiment in the configuration is that the Fourier transformer (fast FFT) or Walsh transform is included in the on-delay compensation value calculator 35c as shown in Fig. 9. A converter and the like become unnecessary, and i-o- becomes unnecessary. Conversely, a dq converter 314 is required in the control arithmetic unit 31. Here, the d-q converter 3 1 4 is an AC voltage generator 3 1 3 generated by the signal VZ f (output signal from the on-delay compensation value calculator 35 c to the AC voltage generator 3 13). This is a converter that converts to a rectangular coordinate system rotating at a frequency of. Necessary when vector control is performed on the AC motor 1, especially the induction motor, and is usually provided in the control calculator 31. The currents id and iq on the d--q axes can be obtained by performing coordinate conversion on the three-phase line currents using the d-q converter 314. The conversion equation is, for example, as shown in equation (6).

(i _u

(6)

As in this case, V Zf driving is performed in three phases, and if on-delay compensation is not performed, the waveform will be as shown by the line current i u in FIG. In single-phase, as shown in Fig. 5, the third harmonic has a three-phase waveform with a phase shift of 120 ° and a sixth harmonic, as shown in Fig. 5. Since they cannot be generated, the corresponding harmonics appear in the 5th and 7th order as a distorted waveform (Y157) as shown in the figure. When the current waveform in which the fifth and seventh harmonics are mixed is subjected to dq conversion, for example, a DC current pulsating in the sixth order as shown in id in FIG. 10 is obtained. Therefore, an on-delay compensation value that minimizes the sixth-order component may be obtained.

Here, it is apparent that the on-delay compensation value can be obtained by using a Fourier transformer (fast FFT) or a Walsh transformer in the on-delay compensation value calculator 35c as in the second embodiment. . However, the following shows that the on-delay compensation value can be obtained without using such a Fourier transformer (fast FFT) or a Walsh transformer.

As described above, it is only necessary to reduce the pulsation of id. For example, as shown in (7) To find the Δid from the minimum and maximum values, take the average value as shown in equation (8) or (9), and extract the difference between the minimum and maximum values, to obtain the Fourier transformer (high-speed FFT) or Walsh transformer Such complicated processing becomes unnecessary, and the on-delay compensation value may be obtained so as to minimize these as shown in the flowchart of FIG. FIG. 11 shows the mouthpiece of the third embodiment described above (STEP130 to STEP132).

― ^L d max― ^l d mm (7)

7 = W

Δ, ¹ dm in (8)

N

^A imean = ~ ∑ ^l d (j) ~ ^l dm in where i dmax: the maximum value of id and i dmin: the minimum value of id.

Although id is used for the sake of explanation, the same can be done using iq, and the method of taking an average and multiplying by a weighting factor as described in the second embodiment is the same as that of the first embodiment. It goes without saying that the same can be done as shown. In addition, since the current and the like differ depending on the frequency and voltage value for exciting the AC motor 1, when obtaining the on-delay compensation Td more precisely, the parameters (voltage, It is clear that it is only necessary to determine the frequency.

In the embodiment described above, the on-delay compensation value is automatically calculated. At this time, the on-delay compensation value calculated value may be an abnormal value due to a failure of the power converter or the like. At that time, it is clear that a mechanism to prevent abnormal operation should be provided by adding a limiter with the value of equation (1) as a typ. Value. I can judge.

The on-delay compensation value calculation start signal Std can be given at an arbitrary timing by providing a switch or the like from outside the control circuit 3. In this case, for example, it can be performed at the time of product shipment or at the time of maintenance after installation, if necessary. Or if you want to do it at power on The Std signal should be automatically generated when the power is turned on. In this case, the Std signal can be generated inside the control circuit 3. In addition, all of the embodiments described above can coexist in the on-delay compensation value calculator 35, and if it is possible to select which method to obtain the on-delay compensation value from outside the control circuit 3, the application will be expanded and the AC motor The on-delay compensation value can be obtained irrespective of the load condition. Furthermore, it goes without saying that the on-delay compensation value calculator described in the present invention can be used for a PWM converter and other power converters. Industrial applicability

According to the present invention, since the deviation of the on-delay compensation value due to the variation of the individual power converters is automatically adjusted, torque ripple due to the deviation of the on-delay compensation value can be prevented, and a highly accurate control device can be realized. In addition, the automatic adjustment increases the allowable range of hardware variation, which has the effect of realizing an inexpensive control device.

Claims

An AC motor control device comprising: an AC motor; a power converter that generates AC power to be supplied to the AC motor by a switching element; and an on-delay compensator that compensates for on-delay of the switching element. A constant DC current is passed through the switching element at at least two switching frequencies, the first switching frequency having a large influence of on-delay and the second switching frequency having little influence of on-delay. Motor control means for calculating the on-delay compensation value based on the difference between the voltage control outputs at least at the two frequencies. The control device (2. In the AC motor control device according to claim 1, wherein the switching element is an IGBT, The AC motor control device according to claim 1, wherein the frequency of (1) is 10 kHz or more and the second frequency is 5 kHz or less. (3.The AC motor control device of claim 1, wherein the switching element 2. An AC motor control device according to claim 1, wherein the first frequency is 2 kHz or more and the second frequency is 1 kHz or less. In an AC motor control device including a power converter that generates AC power to be supplied to the AC motor by a switching element and an on-delay compensator that compensates for the on-delay of the switching element, the AC motor has a sine wave. Means for exciting with a wavy single-phase alternating current, means for changing the on-delay compensation value of the on-delay compensator while exciting with the single-phase alternating current exciting means, and the on-delay compensation value An AC motor control device characterized by comprising means for obtaining an on-delay compensation value by which the distortion of the zero-cross portion of the current flowing in the AC motor is substantially minimized by changing the AC motor. In an AC motor control device including a power converter that generates AC power to be supplied to an AC motor by a switching element and an on-delay compensator that compensates for the on-delay of the switching element, the AC motor has a sine wave. Means for performing a Fourier transform or a Waltz transform on a current excited by a wavy single-phase alternating current, and an on-delay compensator for minimizing a harmonic component obtained by the Fourier transform or the Waltz transform. Means for determining an on-delay compensation value by changing the on-delay compensation value, and based on the determined on-delay compensation value. AC motor control apparatus characterized by operating the can the Ondi ray compensator. An AC motor control apparatus including an AC motor, a power converter that generates AC power supplied to the AC motor by a switching element, and an on-delay compensator that compensates for on-delay of the switching element. Means for converting a current flowing by exciting the motor with a sine-wave AC voltage into a current of a two-axis orthogonal coordinate system rotating at the frequency of the AC voltage; and at least one of the currents converted to the orthogonal coordinate system. And means for obtaining an on-delay compensation value by changing an on-delay compensation value of the on-delay compensator so as to minimize pulsation of one axis. Based on the obtained on-delay compensation value, the on-delay compensator is provided. An AC motor control device characterized by operating. An AC motor control apparatus comprising: an AC motor; a power converter that generates AC power supplied to the AC motor by a switching element; and an on-delay compensator that compensates for an on-delay of the switching element. Means for Fourier-transforming or Walsh-transforming the current flowing by exciting the motor with a sine-wave AC voltage; and the on-delay compensator so as to minimize the harmonic component obtained by the Fourier-transforming or Waltz-transforming. An AC motor control device comprising means for obtaining an on-delay compensation value by changing an on-delay compensation value, and operating the on-delay compensator based on the obtained on-delay compensation value. The AC motor control device according to any one of claims 1 to 7, wherein an instruction to start a function of calculating the on-delay compensation value can be given. An AC motor control device including an AC motor, a power converter that generates AC power to be supplied to the AC motor by a switching element, and an on-delay compensator that compensates for on-delay of the switching element. The on-delay compensator controls the switching element to generate a constant DC current at at least two switching frequencies, a first switching frequency having a large influence of an on-delay and a second switching frequency having a small influence of an on-delay. A first on-delay compensator having means for controlling the flow so as to flow, and means for obtaining the on-delay compensation value based on a difference between the voltage control outputs at least at the two frequencies; and a sinusoidal single-phase AC exciting means and the on-delay compensator while energizing by the single-phase AC exciting means. A second means for changing an on-delay compensation value and a means for obtaining an on-delay compensation value by which the distortion of the zero-cross portion of the current flowing through the AC motor is substantially minimized by changing the on-delay compensation value. An on-delay compensator, a means for performing a Fourier transform or a Walsh transform on a current flowing by exciting the AC motor with a sinusoidal single-phase AC, and the Fourier transform or a Walsh transform. A third on-delay compensator having a means for obtaining an on-delay compensation value by changing an on-delay compensation value of the on-delay compensator so as to minimize a harmonic component; Means for converting the current excited and flowing into the two-axis orthogonal coordinate system rotating at the frequency of the AC voltage, and the current converted to the orthogonal coordinate system A fourth on-delay compensator having means for obtaining an on-delay compensation value by changing an on-delay compensation value of the on-delay compensator so as to minimize at least one-axis pulsation; and Means for Fourier-transform or Waltz-transform the current excited by the AC voltage, and the on-lay compensator for minimizing the harmonic component obtained by the Fourier transform or the Walsh transform. An AC motor control device, comprising: a fifth on-delay compensator having means for obtaining an on-delay compensation value by changing an on-delay compensation value, wherein the first to fifth on-delay compensators can be selected. 0. A power conversion device comprising: power conversion means for converting power using a switching element to supply power to a load; and control means for controlling switching of the power converter, wherein the control means includes the switching element. A power conversion device, comprising: an on-delay compensating means for obtaining an on-delay compensation value of the above, wherein the on-delay compensating means performs on-delay compensation of the switching element.

1. In a power converter including a power converter that obtains AC power by a switching element and supplies the AC power to an AC motor, and a control unit that controls switching of the power converter, a signal from the outside of the control unit is used. Respond An on-delay compensation means for obtaining an on-delay compensation value of the switching element, and performing on-delay compensation based on the on-delay compensation value obtained by the on-delay compensation means.

2. An AC motor, a power converter that receives the AC power, converts it into AC power of an arbitrary frequency by a switching element, and supplies the AC power to the AC motor, and an on-delay compensator that compensates for the on-delay of the switching element. An AC motor control device provided with a control circuit having an on-delay compensation value calculating means for calculating an on-delay compensation value based on an on-delay detected by operating the switching element, and an on-delay compensation value calculating means. An AC motor control device comprising: means for starting a calculation; and means for compensating for the on-delay of the switching element based on the calculation result of the on-delay compensation value calculation means.

3. An AC motor, a power converter that receives DC power, converts the DC power into AC power by a switching element, and supplies the AC power to the AC motor, and a control circuit including an on-delay compensator that compensates for the on-delay of the switching element. In an AC motor control device, an on-delay compensation value adjusting means for automatically adjusting an on-delay compensation value based on at least one of a voltage, a current, and a frequency; and an on-delay from outside the control circuit. Means for inputting a signal to start adjustment of the compensation value, and means for starting adjustment of the on-delay compensation value in response to the input of the on-delay compensation value adjustment start signal.

4. A control method for a power conversion device, comprising: power conversion means for converting power using a switching element to supply power to a load; and control means for controlling switching of the power converter. An on-delay compensation value is obtained by operating the switching element, and the on-delay compensation value is used to calculate the on-delay compensation value of the switching element. A control method for a power converter that performs on-delay compensation.

5. A method of controlling a power converter, comprising: a power converter that obtains AC power by a switching element and supplies the AC power to an AC motor; and a control unit that controls switching of the power converter. Operating the switching element in response to a signal from the switching element, then obtaining an on-delay compensation value based on the operation of the switching element, and performing on-delay compensation based on the obtained on-delay compensation value. A control method for an electric power conversion device characterized by the following.

6. An AC motor, a power converter that receives the AC power, converts the AC power into an AC power of an arbitrary frequency by a switching element, and supplies the AC power to the AC motor, and an on-delay compensation unit that compensates for the on-delay of the switching element. In the control method of the AC motor control device provided with the control circuit having the control circuit, the on-delay compensation value calculation means is started at a predetermined timing to obtain the on-delay compensation value, and the obtained on-delay compensation value is calculated based on the obtained on-delay compensation value. A control method of an AC motor control device for compensating on-delay of the switching element.

7. An AC motor, a power converter that receives DC power, converts it into AC power by a switching element and supplies the AC power to the AC motor, and a control circuit having an on-delay compensator that compensates for the on-delay of the switching element. An on-delay compensation value calculator for automatically calculating an on-delay compensation value based on values corresponding to at least one of voltage, current, and frequency; and the control circuit. Means for inputting a signal for starting an on-delay compensation value calculation from outside the AC motor control means for starting the on-delay compensation value calculation in response to the input of the on-delay compensation value calculation start signal How to control the device.