JP2002223600A - Motor controller - Google Patents

Abstract

PROBLEM TO BE SOLVED: To reduce higher harmonic current flowing to an AC motor. SOLUTION: This motor controller is equipped with fundamental wave current control circuits 1-5 and 8, which control the fundamental wave components of motor currents iu, iv, and iw with a dq-coordinate system consisting of a d axis, corresponding to the excitation current components of the currents iu, iv, and iw flowing to a three-phase AC motor M and a q-axis, corresponding to torque current components and rotating synchronously with motor's rotation, and higher harmonic current control circuits 8-12 which control the higher harmonic components contained in the motor currents iu, iv, and iw with an orthogonal coordinate system (higher harmonic coordinate system) rotating at a frequency which is integral times that of the frequency of the fundamental wave components of the motor currents iu, iv, and iw; and this generates the voltage command value vu, vv, and vw of each phase of a three-phase AC coordinate system, by adding up the outputs of the fundamental wave current control circuits 1-5 and 8 and the outputs of the higher harmonic current control circuits 8-12, and controls the drive of the three-phase motor M.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a motor control device, and more particularly to a motor control device for reducing a harmonic current flowing in a three-phase AC motor.

[0002]

2. Description of the Related Art In general, in a current control circuit of a three-phase AC motor, a control operation is performed by converting a three-phase AC into a DC in order to facilitate the calculation (for example, Japanese Patent Application Laid-Open No. Hei 08-3).
No. 31885). FIG. 25 shows a configuration of a conventional control device for a three-phase AC motor. In the control operation performed by the conventional motor control device, the direction of the exciting current component among the currents flowing through the three-phase AC motor was set to the d-axis, and the direction of the torque current component was set to the q-axis orthogonal to the d-axis. A rotating rectangular coordinate system (dq coordinate system) is used. In a rotating rectangular coordinate system, a current control operation is performed using a DC current value obtained by converting a three-phase AC current value to reduce a control deviation of the current.

[0003] The AC motor is provided with a rotor having an internally embedded magnet structure and a stator having a concentrated winding structure as shown in FIG. 7 for miniaturization and high efficiency. The rotor can effectively use magnet torque and reluctance torque. The motor having such a rotor is an IPM (Inte
rior Permanent-magnet Motor). The stator can greatly reduce the coil end. The motor with the rotor and stator having the above-described structure
It is called a concentrated winding IPM motor and is attracting attention as a small-sized motor capable of realizing high efficiency.

[0004]

However, the above-described concentrated winding IPM motor has a characteristic that a spatial harmonic is large. This is because a motor having a concentrated winding structure, such as a concentrated winding IPM motor, has a small number of slots per pole, and therefore has a non-uniform magnetic flux distribution as compared with a motor having a distributed winding structure. The reason why the magnetic flux distribution is not uniform will be described.

FIG. 8 shows an SPM motor having a surface magnet structure in which the rotor surface is covered with a magnet. Unlike the SPM motor shown in FIG. 8, in the IPM motor having the internal embedded magnet structure shown in FIG. 7, there are a portion where the magnet is embedded and a portion where the magnet is not present along the circumference of the rotor. Therefore, the distribution of the magnetic flux is uniform in the SPM motor in which the rotor surface is covered with the magnet,
In an IPM motor, a change in magnetic flux is large, and a spatial harmonic component is large.

When the spatial harmonic of the motor increases, the harmonic component of the current flowing through the motor increases, so that there is a problem that the effect of improving the efficiency of the motor decreases and the torque ripple increases. In addition, since the harmonic component is superimposed on the fundamental component of the current, there is a problem that the peak value of the current increases.

An object of the present invention is to provide a motor control device for reducing a harmonic current flowing in an AC motor.

[0008]

(1) The first to third aspects of the present invention will be described with reference to FIG. 1 showing the configuration of the first embodiment of the present invention. AC motor M
The motor current i is composed of a d-axis corresponding to the exciting current components of the currents iu, iv, and iw and a q-axis corresponding to the torque current component.
fundamental current control circuits 1 to 5 and 8 for controlling fundamental wave components of u, iv and iw, and a rectangular coordinate system (high harmonics) rotating at an integral multiple of the frequency of the fundamental wave components of motor currents iu, iv and iw. And harmonic current control circuits 8 to 12 for controlling harmonic components included in the motor currents iu, iv and iw in a wave coordinate system. The outputs of the fundamental current control circuits 1 to 5 and 8 and the harmonic current control are provided. The above object is achieved by adding the outputs of the circuits 8 to 12 to generate the voltage command values vu, vv, vw of each phase of the three-phase AC coordinate system and controlling the driving of the three-phase AC motor M. (2) In the motor control device according to the second aspect, the motor currents iu, i
A rectangular coordinate system that rotates at the frequency of a harmonic component of a predetermined order generated when v and iw are controlled is set, and the harmonic current control circuits 8 to 12 control the harmonic components included in the motor currents iu, iv, and iw. The harmonic current is controlled so that the harmonic component of a predetermined order becomes zero. (3) In the motor control device according to the third aspect, the motor currents iu, iv, and iw are converted into dq
The currents are converted into currents id and iq in the coordinate system, and the harmonic components of the currents id and iq in the dq coordinate system are detected and converted into harmonic currents in the harmonic coordinate system. (4) The invention according to claim 4 will be described with reference to FIG. 2 showing the configuration of the second embodiment of the invention. The motor control device according to claim 4 provides harmonic current control circuits 8, 9, 11,. 21,
22, a harmonic component of the motor currents iu, iv, iw is input and converted to a harmonic current in a harmonic coordinate system. (5) The invention according to claim 5 will be described with reference to FIG. 3 showing the configuration of the third embodiment of the invention. The motor control device according to claim 5 includes harmonic current control circuits 9, 11, 33, 3
5, 36, the motor currents iu, iv, iw are set to the currents i in the αβ rectangular coordinate system fixed to the stator side of the motor M.
are converted into α and iβ, and the harmonic components of the currents iα and iβ in the αβ coordinate system are input and converted into harmonic currents in the harmonic coordinate system. (6) According to a sixth aspect of the present invention, the harmonic order to be controlled in the harmonic current control circuit is switched according to the driving state of the motor. (7) Referring to FIG. 9 showing the configuration of the fifth embodiment of the present invention, the present invention of claim 7 is the motor control device of claim 3, wherein the harmonic current control circuits 8, 10, 1
1, 12, 50 are current command values id *, iq * in the dq coordinate system.
Current response value prediction circuit 50 for predicting current response values id_i, iq_i for the current, and current response values id_i, iq predicted by current response value prediction circuit 50 from current values id, iq of the dq coordinate system.
_i is subtracted to detect harmonic currents id_h and iq_h. (8) Referring to FIG. 18 showing the configuration of the sixth embodiment of the invention, the invention of claim 8 is the motor control device according to claim 4, wherein the harmonic current control circuits 8, 11,.
21, 22, 50B and 54 are motor current command values iu *,
a current response value prediction circuit 50B for predicting the current response values iu_i, iv_i for iv *, and a current response value iu_i, predicted by the current response value prediction circuit 50B from the motor current values iu, iv.
A harmonic current detection circuit 50B is provided for detecting harmonic currents iu_h and iv_h by subtracting iv_i. (9) Referring to FIG. 21 showing the configuration of the seventh embodiment of the present invention, the ninth aspect of the present invention is the motor control device according to the fifth aspect, wherein the harmonic current control circuits 11, 3
3, 34, 35, 36, 50D, and 55 are current response values iα_i, i for current command values iα *, iβ * in the αβ coordinate system.
A current response value prediction circuit 50D for predicting β_i, and a current response value iα_i, iβ_i predicted by the current response value prediction circuit 50D from the current values iα, iβ in the αβ coordinate system to detect harmonic currents iα_h, iβ_h Harmonic current detection circuit 50
D. (10) According to a tenth aspect, in the motor control device according to any one of the seventh to ninth aspects, the current response value prediction circuit is a low-pass filter. (11) The invention according to claim 11 is the motor control device according to claim 10, wherein the time constant of the low-pass filter changes as the state of the motor changes. (12) According to a twelfth aspect of the present invention, in the motor control device of the first to eleventh aspects, a plurality of sets of harmonic current control circuits corresponding to a plurality of harmonic currents of a plurality of orders are provided. (13) According to a thirteenth aspect of the present invention, in the motor control device according to the twelfth aspect, the harmonic order to be controlled in the harmonic current control circuit is determined in descending order of harmonic components included in the motor current. It is.

In the section of the means for solving the above-described problems, a diagram of one embodiment is used to explain the present invention in an easy-to-understand manner, but the present invention is not limited to the embodiment. is not.

[0010]

(1) According to the first aspect of the present invention, it is possible to convert a harmonic component included in a motor current into a DC amount for an AC motor such as a concentrated winding IPM motor and control the same. Harmonic components can be efficiently and sufficiently reduced. In particular, for a concentrated winding IPM motor, harmonic components can be reduced from the motor current to achieve downsizing and high efficiency, and further reduce the torque ripple and the peak value of the current. (2) According to the second aspect of the invention, in addition to the effect of the first aspect, it is possible to greatly reduce a harmonic component centered on a predetermined order. (3) According to the third aspect of the present invention, when the motor current is converted into a dq coordinate system current, the fundamental wave component becomes a DC amount, and the harmonic component becomes an AC amount. Therefore, the harmonic component can be easily separated from the motor current, and the harmonic component can be reliably reduced. (4) According to the invention of claim 4, the fundamental wave current control circuit converts the motor current into the dq-axis current to extract a fundamental wave component, so that the fundamental wave component matches the fundamental wave current command value. Feedback control, while the harmonic current control circuit
Since the harmonic component of the motor current is extracted and the feedback control is performed so that the harmonic component matches the harmonic current command value (= 0), the interference between the fundamental current control and the harmonic current control is small, and a good Current control characteristics are obtained. (5) According to the fifth aspect of the present invention, the amount of calculation is reduced as compared with the case where the current control calculation is performed in the three-phase AC coordinate system. (6) According to the invention of claim 6, it is possible to effectively reduce the harmonic current generated according to the driving state of the motor. (7) According to the seventh to ninth aspects, even when the fundamental current changes, the change in the fundamental current is not detected as the harmonic current, and the harmonic current is reliably detected. Can be. Thereby, the accuracy of motor control can be improved. (8) According to the eleventh aspect of the invention, even when the control response value of the fundamental wave current changes depending on the state of the motor, the time constant of the low-pass filter is set to a value corresponding to the state of the motor. Can be improved in the accuracy of the predicted response value. (9) According to the twelfth and thirteenth aspects, it is possible to further reduce harmonic components contained in the motor current.

[0011]

DESCRIPTION OF THE PREFERRED EMBODIMENTS << First Embodiment >> FIG. 1 is a control block diagram showing the configuration of a first embodiment of a motor control device according to the present invention. The motor control device performs vector control using a three-phase AC motor to realize torque control equivalent to that of a DC motor. That is, the torque current component is proportional to the output torque of the motor by decoupling the excitation current component and the torque current component of the motor current.
That is, when the amplitude of the magnetic flux vector of the rotating magnetic field generated by the rotation driving of the AC motor is controlled to be constant, the torque current vector orthogonal to the magnetic flux vector is proportional to the motor torque.

In order to perform the above control, the motor control device of the first embodiment includes a fundamental current control circuit and a harmonic current control circuit. The fundamental current control circuit
This is a circuit for controlling the fundamental wave components of the motor currents iu, iv, iw using the dq coordinate system. The dq coordinate system includes a d-axis corresponding to the exciting current component of the three-phase current iu, iv, iw flowing through the three-phase AC motor M, and a q-axis corresponding to the torque current component, and rotates in synchronization with the rotation of the motor. Coordinate system.
The harmonic current control circuit is a circuit that controls a harmonic component included in the motor currents iu, iv, and iw using a harmonic coordinate system. The harmonic coordinate system is a rectangular coordinate system that rotates at a frequency of a harmonic component of a predetermined order generated when the motor currents iu, iv, and iw are controlled using only the fundamental current control circuit. This is a coordinate system that rotates at a frequency that is an integral multiple of the frequency of the fundamental wave components of iv and iw.

The fundamental wave current control circuit includes a torque control unit 1,
It includes a fundamental wave current controller 2, a dq / 3-phase converter 3, a power converter 4, a phase speed calculator 5, and a three-phase / dq converter 8. The configuration of this fundamental current control circuit is shown in FIG.
This is the same as the configuration of the conventional motor control device shown in FIG. The torque control unit 1 calculates the torque command value Te * and the motor rotation speed ω
Based on e, a d-axis current command value id * as an exciting current component and a q-axis current command value iq * as a torque current component are calculated using a current command value table. The calculated current command values id * and iq * are sent to the fundamental current control unit 2.

A fundamental wave current controller (dq axis current controller) 2
Calculates the d-axis and q-axis fundamental wave voltage command values vd * and vq * in order to match the d-axis and q-axis actual currents id and iq with the current command values id * and iq *, respectively. dq / 3-phase converter 3
Are based on the phase θe of the dq coordinate system viewed from the three-phase AC coordinate system, and the d-axis and q-axis voltage command values (vd * + vd ′), (v
q * + vq ′) are converted into three-phase AC voltage command values vu *, vv *, vw *. d-axis and q-axis voltage command values (vd * + vd '), (v
q * + vq ') will be described later. The converted three-phase AC voltage command values vu *, vv *, vw * are sent to the power conversion unit 4.
The power conversion unit 4 includes a power conversion element such as an IGBT,
The DC voltage of a DC power source (not shown) such as a battery is switched based on the three-phase AC voltage command values vu *, vv *, vw *, and the three-phase AC voltages U, V, W are applied to the three-phase AC motor M. I do.

The encoder PS is connected to a three-phase AC motor M and detects the rotational position θm of the motor M. The detected rotational position θm is sent to the phase velocity calculating section 5. The phase speed calculation unit 5 calculates the rotation speed ωe of the motor M and the phase θe of the dq coordinate system viewed from the three-phase AC coordinate system based on the rotation position signal θm sent from the encoder PS. The current sensors 6 and 7 are provided with the actual current i of the U-phase and V-phase
u and iv are respectively detected. The detected U-phase current iu and V-phase current iv are sent to the three-phase / dq converter 8. 3 phase / dq
The converter 8 converts the actual currents iu, iv, iw of the three-phase AC motor M based on the phase θe of the dq coordinate system viewed from the three-phase AC coordinate system.
(= −iu−iv) is converted to the actual current id on the d-axis and the actual current iq on the q-axis.
Convert to

The harmonic current control circuit includes a three-phase / dq converter 8, a high-pass filter 9, a dq / dhqh converter 10,
A harmonic current controller 11 and a dhqh / dq converter 12 are provided. The high-pass filter 9 has a d-axis real current i
A filter process is performed on the real current iq on the d and q axes to extract a harmonic component. The dq / dhqh conversion unit 10 is a rectangular coordinate system (a harmonic coordinate system) that rotates at a frequency of a harmonic component of a predetermined order generated when the motor currents iu, iv, and iw are controlled only by the above-described fundamental wave current control circuit. ) Has dhqh, and converts the harmonic components of the real current id on the d-axis and the real current iq on the q-axis into the real currents idh, iqh of the harmonic coordinate system dhqh. Assuming that the phase of the dhqh coordinate system viewed from the dq coordinate system is θeh, the actual currents idh and iqh of the dhqh coordinate system can be obtained by the following equation (1).

(Equation 1)

The harmonic current controller 11 controls the motor current i
The harmonic current is controlled so that the harmonic component of the predetermined order among the harmonic components included in u, iv, and iw becomes zero.
Therefore, the harmonic current control unit (dhqh-axis current control unit) 1
1 is the dh-axis and qh-axis harmonic voltage command values vdh * and vqh * for matching the actual currents idh and iqh of the dh-axis and qh-axis with the current command values idh * = 0 and iqh * = 0, respectively. Calculate.
The dhdq / dq converter 12 converts the dh-axis and qh-axis harmonic voltage command values vdh * and vqh * into d-axis and q-axis harmonic voltage command values vd 'and vq', respectively. This conversion is given by equation (1)
What is necessary is just to perform the reverse conversion. The converted voltage command value vd ',
vq 'is sent to adders 13 and 14. Adder 13,
Numeral 14 adds the fundamental voltage command values vd *, vq * generated by the fundamental current control unit 2 and the harmonic voltage command values vd ′, vq ′ generated by the harmonic current control circuit. D-axis voltage command value (vd * + vd ') and q-axis voltage command value (vq * + vq')
Get.

A high-pass filter 9, a dq / dhqh converter 10, a harmonic current controller 11, a dhqh / dq converter 12 shown in FIG.
Excluding the adders 13 and 14, the current control circuit of the conventional motor control device shown in FIG. 25, that is, a current control circuit that controls the motor current in a dq coordinate system that rotates in synchronization with the rotation of the motor. In the current control calculation using only the dq coordinate system, it is difficult to ensure the followability of the actual current to the current command value up to the frequency band of the harmonic current caused by the spatial harmonic of the motor. Therefore, as described above, there are problems that the effect of improving the efficiency of the concentrated winding IPM motor is reduced, the torque ripple is increased, or the peak value of the current is increased.

This problem will be described in detail. Since the dq coordinate system is a coordinate system that rotates in synchronization with the rotation of the motor, the fundamental wave current of the motor is a DC amount in the dq coordinate system. On the other hand, the angular frequency ω of the harmonic current in the dq coordinate system
eh_dq is represented by the following equation (2), where ωeh is the angular frequency of the harmonic current and ωe is the fundamental angular frequency of the motor current.

Ωeh_dq = ωeh−ωe (2) As is apparent from equation (2), the harmonic component of the motor current does not become a DC amount even in the dq coordinate system. For this reason, when the rotation speed of the motor increases and the frequency of the motor current increases, the followability of the fundamental component of the motor current is good,
The frequency of the harmonic component of the motor current increases according to the rotation speed of the motor, and the actual current cannot follow the current command value.

In order to solve the above-mentioned problem, the motor control device of the first embodiment uses the harmonic current control circuits 8 to 12 and the adders 13 and 14 shown in FIG. The current followability of the harmonic component is improved, and the harmonic component of a predetermined order is reduced. For the sake of simplicity, it is assumed in this embodiment that the k-th harmonic component is reduced.

The fundamental wave components of the d-axis and q-axis actual currents id and iq output from the three-phase / dq converter 8 are DC quantities.
The harmonic component is an AC amount. The high-pass filter 9 is
Only harmonic components are extracted from the actual currents id and iq. The extracted harmonic components are sent to the dq / dhqh converter 10.
The dq / dhqh conversion unit 10 converts the k-th harmonic component included in the actual currents id and iq into a phase dh that rotates by a phase (θe_h−θe).
It is converted to the actual currents idh and iqh in the qh harmonic coordinate system. Here, θe_h is the phase of the k-th harmonic current. Since the k-th harmonic component can be set in advance, the phase θe_h
−θe can be obtained by calculation. The converted actual currents idh and iqh are DC quantities. Therefore, when the current control operation is performed in the dhqh coordinate system, the ability to follow the current command value (= 0) of the k-th harmonic current is greatly improved. As a result, harmonic currents included in the motor currents iu, iv, iw can be reduced. In particular, the k-th and higher harmonic currents can be significantly reduced.

When a conventional motor control device is used to drive a concentrated winding IPM motor having a large spatial harmonic component,
FIG. 5 shows a waveform of the U-phase current with respect to the U-phase current command value.
FIG. 6 shows a waveform of the U-phase current with respect to the U-phase current command value when the same IPM motor is driven using the motor control device of the first embodiment. When a conventional motor control device is used, a large harmonic component is included in the motor current as is apparent from FIG. On the other hand, when the motor control device according to the first embodiment is used, harmonic components are greatly reduced as is clear from FIG.

As described above, according to the motor control device of the first embodiment, it is possible to reduce harmonic components centered on a predetermined order included in the motor current.

In the motor control device of the first embodiment described above, an example in which the harmonic current of an arbitrary predetermined order k is reduced has been described. Alternatively, the order k of the harmonic current to be reduced may be switched. That is, the harmonic current component generated when the driving state of the motor changes also changes. Therefore, it is necessary to reduce the highest harmonic current component according to the driving state of the motor.

In the above-described first embodiment, an example has been described in which the fundamental component and the harmonic component are extracted from the actual currents id and iq on the dq axes. On the dq axes, the fundamental wave component is a DC amount,
Since the harmonic component is an alternating current, it is easier to separate the fundamental component and the harmonic component as compared with the methods performed in the second and third embodiments described later.

In the above-described first embodiment, the harmonic coordinate system is changed to the motor current i by only the fundamental current control circuits 1 to 8.
An example is shown in which a rectangular coordinate system dhqh is rotated at the frequency of a harmonic component of a predetermined order generated when u, iv, and iw are controlled. A similar harmonic component reduction effect can be obtained even when an orthogonal coordinate system that rotates at a frequency that is an integral multiple of the frequency of the fundamental component of the motor current is used as the harmonic coordinate system.

<< Second Embodiment >> In the above-described first embodiment, the dq-axis voltage command values vd *, vq * for the fundamental wave and the dq-axis voltage command values vd ', vq' for the harmonic wave. And the final dq-axis voltage command value (vd * + vd '), (vq * + v
q ′) is obtained, and the three-phase voltage command value vu is obtained by dq / 3-phase conversion.
An example of conversion into *, vv *, vw * has been shown. In the second embodiment, the three-phase AC voltage command values vu *, vv *, v
w * and the three-phase AC voltage command values vu ', vv', and vw 'for the harmonics are obtained, and they are added to obtain the final three-phase AC voltage command values (vu * + vu'), (vv * + vv). '), (Vw * + vw').

FIG. 2 is a diagram showing the configuration of the motor control device according to the second embodiment. The same reference numerals are given to the same devices as those shown in FIG. 1, the description is omitted, and the devices are represented by a single line diagram. The fundamental wave current control circuit is the same as that of the first embodiment shown in FIG. 1, and a description thereof will be omitted.

In the harmonic current control circuit, a high-pass
The filter 9 filters the actual currents iu and iv of the three-phase AC motor M to extract harmonic components. 3 phase / dhqh
The conversion unit 21 has a harmonic coordinate system dhqh, and converts the harmonic number components of the motor currents iu and iv into actual currents idh and iqh of the harmonic coordinate system dhqh. As described above, the harmonic coordinate system refers to the motor currents iu, iv,
This is an orthogonal coordinate system that rotates at the frequency of a harmonic component of a predetermined order generated when iw is controlled. Assuming that the phase of the dhqh coordinate system viewed from the three-phase coordinate system is θehs, the actual currents idh and iqh of the dhqh coordinate system can be obtained by the following equation (3).

[Equation 3]

The dhqh / 3-phase converter 22 converts the dh-axis voltage command values vdh *, q sent from the harmonic current controller 11
The h-axis voltage command value vqh * is converted into three-phase AC voltage command values vu ', vv', vw 'for harmonics. This conversion may be performed by performing the conversion reverse to the expression (3). Adders 13 and 14 provide three-phase AC voltage command values vu for the fundamental wave calculated by the fundamental wave current control circuit.
*, Vv *, vw * and the three-phase AC voltage command values vu ', vv', vw 'for the harmonics calculated by the harmonic current control circuit, and the final three-phase AC voltage command value ( vu * + vu '), (v
v * + vv ') and (vw * + vw').

When the motor control device according to the second embodiment is used, a motor current waveform substantially similar to the waveform shown in FIG. 6 is obtained. That is, similarly to the motor control device of the first embodiment, it is possible to reduce harmonic components centered on the predetermined order included in the motor current. In the motor control device according to the second embodiment, the command values for the fundamental wave and the harmonic are calculated in the three-phase AC coordinate system.
The amount of calculation processing is larger than in the first embodiment in which calculation is performed in the dq coordinate system.

<< Third Embodiment >> In the first embodiment described above, an example in which the voltage command value calculation is performed in the dq coordinate system is described. In the second embodiment, the voltage is calculated in the three-phase AC coordinate system. Each example in which the command value calculation is performed has been described. In the third embodiment, a voltage command value calculation is performed in the αβ coordinate system.

The above-described three-phase AC coordinate system is a stationary coordinate system fixed to the stator of the motor, and has a U-phase, V-phase, and W-phase axes shifted by 120 degrees. On the other hand, the αβ coordinate system is an orthogonal coordinate system fixed to the stator. Generally, an αβ coordinate system is set with the α axis having the same phase as the U axis of a three-phase AC coordinate system. In this αβ coordinate system, the three physical quantities of the three-phase AC coordinate system can be handled by two orthogonal physical quantities, so that the processing amount of the command value calculation is almost the same as that of the dq coordinate system of the above-described first embodiment. become.

FIG. 3 is a diagram showing the configuration of the motor control device according to the third embodiment. The same reference numerals are given to the same devices as those shown in FIG. 1, the description is omitted, and the devices are represented by a single line diagram. The fundamental wave current control circuit according to the third embodiment differs from the fundamental wave current control circuit shown in FIG.
A q / αβ conversion unit 31 and an αβ / 3 phase conversion unit 32 are newly added, and a three phase / αβ conversion unit 33 and an αβ / dq conversion unit 34 are used instead of the three phase / dq conversion unit 8.

The dq / αβ converter 31 converts the dq-axis fundamental voltage command values vd * and vq * calculated by the fundamental current controller 2 into αβ-axis fundamental voltage command values vα * and vβ *. αβ
The / 3-phase conversion unit 32 converts the final αβ axis voltage command values (vα * + vα ′) and (vβ * + vβ ′) described later into three-phase voltage command values vu *, vv *, and vw *. 3 phase / αβ conversion unit 33
Converts the actual currents iu, iv, iw (= -iu-iv) of the three-phase AC motor M into actual currents iα, iβ on the αβ axis based on the fundamental current phase θe. The αβ / dq conversion unit 34 calculates α
The real currents iα and iβ on the β axis are converted to the real currents id and iq on the dq axis.

In the harmonic current control circuit according to the third embodiment, instead of the dq / dhqh conversion unit 10 and the dhqh / dq conversion unit 12 of the harmonic current control circuit shown in FIG.
An hqh converter 35 and a dhqh / αβ converter 36 are used, respectively.

The high-pass filter 9 filters out the actual currents iα and iβ on the αβ axis to extract harmonic components. The extracted harmonic components are sent to the αβ / dhqh converter 35. The αβ / dhqh conversion unit 35 calculates the harmonic coordinate system d
hqh, and converts the harmonic components of the αβ-axis currents iα and iβ into the actual currents idh and iqh of the harmonic coordinate system dhqh. As described above, the harmonic coordinate system is an orthogonal coordinate system that rotates at the frequency of a harmonic component of a predetermined order generated when the motor currents iu, iv, and iw are controlled only by the fundamental wave current control circuit. The dhqh / αβ conversion unit 36 controls the harmonic current control unit 11
Dh and qh axis harmonic voltage command values vdh sent from
*, Vqh * are converted into αβ axis harmonic voltage command values vα ′, vβ ′, respectively.

The adders 13 and 14 are composed of the αβ axis fundamental voltage command values vα * and vβ * calculated by the fundamental current control circuit and the αβ axis harmonic voltage command value v calculated by the harmonic current control circuit.
α ′ and vβ ′ are added, and the final αβ axis voltage command value (v
α * + vα ′) and (vβ * + vβ ′).

The final αβ axis voltage command value (vα * + v
α ′) and (vβ * + vβ ′) are converted into three-phase AC voltage command values vu *, vv *, and vw * by the αβ / 3-phase converter 32. The power converter 4 includes three-phase AC voltage command values vu *, vv *,
The three-phase AC voltages U, V, and W are applied to the three-phase AC motor M based on vw *.

When the motor control device according to the third embodiment is used, a motor current waveform substantially similar to the waveform shown in FIG. 6 is obtained. That is, similarly to the motor control device of the first embodiment, it is possible to reduce harmonic components centered on a predetermined order included in the motor current.

<< Fourth Embodiment >> The above-described first to third embodiments
In each of the embodiments, an example has been shown in which harmonic components centered on a single order included in the motor current are reduced. In the fourth embodiment, an example is shown in which harmonic components centered on two orders, here the fifth and seventh orders, whose components are generally large, are reduced.

FIG. 4 is a diagram showing a configuration of a motor control device according to the fourth embodiment. The same reference numerals are given to the same devices as those shown in FIG. 1, the description is omitted, and the devices are represented by a single line diagram. The configuration of the fundamental current control circuit of the fourth embodiment is the same as the configuration of the fundamental current control circuit of the first embodiment shown in FIG.

The difference from the motor control device of the first embodiment is a harmonic current control circuit. That is, the motor control device according to the fourth embodiment includes two sets of the harmonic current control circuits according to the first embodiment shown in FIG. One of the two harmonic current control circuits includes a three-phase / dq converter 8, a high-pass filter 9, and a dq / dh1qh1 converter 1.
0A, a harmonic current controller 11 and a dh1qh1 / dq converter 12A. Another harmonic current control circuit includes a three-phase / dq converter 8, a high-pass filter 9, d
It comprises a q / dh2qh2 converter 10B, a harmonic current controller 11, and a dh1qh1 / dq converter 12B.

Dq / dh1qh1 converter 10A and dq / dh2
The qh2 conversion unit 10B is a dq / dhqh conversion unit 1 shown in FIG.
It is the same as 0. However, the dq / dh1qh1 converter 10A converts the harmonic components of the real currents id and iq on the dq axes into a rectangular coordinate system (rotating in synchronization with the phase (θeh1−θe) of the fifth harmonic component of the motor current). (Harmonic coordinate system) dh1qh1 is converted into actual currents idh1, iqh1. Also, dq
The / dh2qh2 conversion unit 10B converts the harmonic components of the real currents id and iq on the dq axes into a rectangular coordinate system (harmonic coordinates) that rotates in synchronization with the phase (θeh2-θe) of the seventh harmonic component of the motor current. (System) This is to convert the actual currents dh2qh2 into the actual currents idh2, iqh2.

The dh1qh1 / dq converter 12A and dh2qh2 /
The dq converter 12B is a dhqh / dq converter 1 shown in FIG.
Same as 2. However, the dh1qh1 / dq converter 12A outputs the harmonic voltage command values vdh1 * for the dh1 axis and the qh1 axis,
vqh1 * is replaced with d-axis and q-axis harmonic voltage command values vd1 ', vq1'
Is converted to Dh2qh2 / dq converter 1
2B is a harmonic voltage command value vdh2 *, v for the dh2 axis and the qh2 axis.
It converts qh2 * into d-axis and q-axis harmonic voltage command values vd2 ', vq2'.

The adders 13 and 14 are provided with the dq-axis fundamental wave voltage command values vd * and vq * calculated by the fundamental wave current control circuit and the fifth
The dq-axis harmonic voltage command values vd1 ', vq1' calculated by the seventh harmonic current control circuit and the dq-axis harmonic voltage command values vd2 ', vq2' calculated by the seventh harmonic current control circuit are added. , Final dq axis voltage command value (vd * + vd1 '+ vd2'), (v
q * + vq1 '+ vq2').

The final dq axis voltage command value (vd * + vd1 ')
+ Vd2 ') and (vq * + vq1' + vq2 ') are converted by the dq / 3-phase converter 3 into three-phase AC voltage command values vu *, vv *, and vw *. The power converter 4 includes a three-phase AC voltage command value vu *,
The three-phase AC voltages U, V, and W are applied to the three-phase AC motor M based on vv * and vw *.

According to the motor control device of the fourth embodiment, the harmonic components contained in the motor current, especially the fifth and the fourth harmonic components, are further compared to the motor control devices of the first to third embodiments. Higher harmonic components centered on the seventh order can be reduced.

The motor control device according to the fourth embodiment has a configuration in which two sets of harmonic control circuits of the motor control device according to the first embodiment are provided. Similarly, a configuration including two sets of harmonic control circuits of the motor control device according to the second embodiment may be provided, or a configuration including two sets of harmonic control circuits of the motor control device according to the third embodiment. It can also be. In the fourth embodiment, since the fifth and seventh harmonic components are large in the harmonic current included in the motor current, the fifth and seventh harmonic components are separated. Although an example of reduction is shown, the order of harmonics to be reduced is not limited to this embodiment. That is, it is only necessary to reduce the order in which the harmonic current contained in the harmonic current is large. Further, in the fourth embodiment, an example has been described in which the harmonic components of the two orders of the fifth and seventh orders are mainly reduced, but three or more harmonic components can also be reduced. In this case, the above-described harmonic current control circuits may be provided by the number of harmonic components to be reduced.

<< Fifth Embodiment >> FIG. 9 is a diagram showing a configuration of a motor control device according to a fifth embodiment. In addition,
The same components as those shown in FIG. 1 are denoted by the same reference numerals, description thereof will be omitted, and a single line diagram will be used. The fundamental wave current control circuit is the same as that of the first embodiment shown in FIG. 1, and a description thereof will be omitted.

The motor control device according to the fifth embodiment is different from the motor control device shown in FIG. That is, in the motor control device according to the first embodiment, the high-pass filter 9 is used to detect the harmonic components of the real currents id and iq on the dq axes, but the motor control device according to the fifth embodiment is used. Then, the harmonic current detection unit 50
Is used to detect harmonic components. The harmonic current detector 50 predicts a current response value for the dq-axis current command values id * and iq *, and calculates the predicted current response value and the dq-axis currents id and iq converted by the three-phase / dq converter 8. Is used to detect the harmonic components of the dq-axis currents id and iq. This method will be described in detail with reference to FIG.

FIG. 10 is a block diagram showing the configuration of the harmonic current detection unit 50. The current response prediction unit 51 calculates the current response prediction value id_ with respect to the current command values id * and iq * on the dq axes.
It has a transfer function G (s) that outputs i, iq_i. When the current control performed by the fundamental wave current control unit 2 is performed by, for example, PI control, the transfer function G (s) can be realized by the first-order low-pass filter 51a as shown in FIG.
In this case, the time constant of the low-pass filter 51a is equal to the time constant of the fundamental current control unit 2.

The current command values id * and iq * on the dq axes are input to the current response prediction unit 51, and the current response prediction values id_i and iq_i are obtained by performing filter processing using, for example, a low-pass filter 51a. 52 and 53 are output.
The subtractor 52 subtracts the d-axis current response predicted value id_i from the d-axis actual current id to obtain a harmonic component id_h of the d-axis current. Further, the subtracter 53 obtains a harmonic component iq_h of the q-axis current by subtracting the predicted q-axis current response value iq_i from the actual q-axis current iq. The dq-axis current command values id *, iq
* The phase and gain characteristics of the predicted current response to
It is equal to the phase characteristic / gain characteristic of the fundamental wave current controller 2.
When the fundamental wave current control unit 2 performs control other than PI control, a transfer function corresponding to the control system may be used.

When the harmonic component of the dq-axis current is detected by using the high-pass filter 9 shown in FIG. 1, when the fundamental current changes, the change in the fundamental current passes through the high-pass filter 9 and becomes higher. May be detected as a component.
If a harmonic component is erroneously detected, an error occurs in the three-phase AC voltage command values vu *, vv *, and vw * sent to the power conversion unit 4, and the accuracy of motor control deteriorates. High pass
Using the harmonic current detection unit 50 instead of the filter 9, d
When the harmonic component of the q-axis current is detected, even when the fundamental current changes, the harmonic components id_h and iq_h do not include a change in the fundamental current. That is, when the current command values id * and iq * on the dq axes change, the predicted current response values id_i and iq_i
Therefore, the harmonic component calculated by subtracting the change in the current response predicted value by the subtracters 52 and 53 does not include the change in the fundamental current.

Referring to FIGS. 13 to 17, control results when a simulation is performed using the motor control device of the first embodiment and a simulation is performed using the motor control device of the fifth embodiment. Is compared with the control result at the time. FIG. 13 is a diagram illustrating a temporal change in the d-axis current command value and the q-axis current command value. FIG. 14 shows a result when the q-axis harmonic current is detected with respect to the current command value shown in FIG. 13 using the motor control device according to the first embodiment. The scale of the vertical axis is -60 [A] to 150 [A].
It is. As is apparent from FIG. 14, the detected q-axis harmonic current includes a change in the fundamental current.

FIG. 15 shows a result when the q-axis harmonic current is detected using the motor control device according to the fifth embodiment with respect to the current command value shown in FIG. The scale of the vertical axis is -20 [A] to 20 [A]. It can be seen that the fluctuation of the detected q-axis harmonic current is small and does not include the change in the fundamental current. FIGS. 16 and 17 show response values to the current command values shown in FIG. 13 when the harmonic current command values idh = 0 and iqh = 0. FIG.
As can be understood from the above, in the control by the motor control device of the first embodiment, the d-axis current fluctuates. On the other hand, in the control by the motor control device of the fifth embodiment, the fluctuation of the d-axis current is suppressed, and the control accuracy is improved. In addition, the responsiveness of the q-axis current to the current command value is also improved.

FIG. 17 is an enlarged view of a part of FIG. 16, showing the control result of the q-axis current command value by the motor control device of the first embodiment and the motor control device of the fifth embodiment. And the results of the control by. As can be seen from the figure, the control by the motor control device of the fifth embodiment improves the control accuracy of the response value of the q-axis current to the current command value. As described above, in the control by the motor control device according to the first embodiment, the change in the fundamental wave current is erroneously detected as the harmonic current.
Both the shaft current and the control accuracy deteriorate. In the control by the motor control device according to the fifth embodiment, since the detected harmonic current does not include the fundamental wave current, the control accuracy of the dq-axis current can be improved.

The time constant of the low-pass filter 51a used in the motor control device according to the fifth embodiment is a fixed value equal to the time constant of the fundamental current control unit 2. This time constant may be variable. In actual control,
The state of the motor M changes such that the resistance of the motor M changes with temperature and the inductance changes with the motor current. In this case, in the control of the first-order lag system in which the time constant is fixed, an error occurs between the current command value and the current response value. To suppress this error, a low-pass filter 5
By making the time constant of 1a variable, it is possible to improve the detection accuracy of the harmonic current.

FIG. 12 is a block diagram showing the configuration of the harmonic current detecting section 50A in which the time constant of the low-pass filter 51a is variable. The time constant table 54 is a table for setting the time constant of the low-pass filter 51aA according to the dq current command values id *, iq *. Current command value i
The relationship between d * and iq * and the time constant of the low-pass filter 51aA is obtained in advance by experiments. The low-pass filter 51aA performs a filtering process using the time constant obtained from the time constant table 54, and obtains a current response predicted value id_
i and iq_i are output to the subtracters 52 and 53, respectively.

According to the motor control device of the fifth embodiment, even when the fundamental current changes, the change in the fundamental current is not detected as the harmonic current, and the harmonic current is reliably detected. Can be detected. Also, the current command value id
By setting the time constant of the low-pass filter 51aA according to * and iq *, it is possible to more accurately detect the harmonic current.

The time constant of the low-pass filter 51aA stored in the time constant table 54 is set to the current command value id.
Instead of * and iq *, a value corresponding to the dq-axis currents id and iq can be used.

Sixth Embodiment A motor control device according to a fifth embodiment is different from the motor control device according to the first embodiment in that the high-pass filter 9 is replaced by the harmonic current detector 50.
It is configured by replacing The motor control device according to the sixth embodiment is configured by replacing the high-pass filter 9 in the motor control device according to the second embodiment with a harmonic current detection unit 50B. Further, a dq / 3-phase converter 55 is provided for inputting the current command values iu * and iv * to the harmonic current detector 50B. FIG. 18 shows the configuration of the motor control device according to the sixth embodiment.

FIG. 19 is a block diagram showing the configuration of the harmonic current detector 50B. The current command values iu * and iv * converted by the dq / 3-phase converter 55 are
1aB. Input current command values iu *, iv *
Is subjected to filter processing by a low-pass filter 51aB to obtain current response predicted values iu_i and iv_i. The subtracter 52 calculates the u-phase current response predicted value iu_i from the u-phase current iu.
To obtain the harmonic component iu_h of the u-phase current. Further, the subtracter 53 obtains a harmonic component iv_h of the v-phase current by subtracting the predicted value of the v-phase current response iv_i from the v-phase current iv. The obtained harmonic components iu_h and iv_h are each 3 phases / d
It is output to the hqh conversion unit 21.

Further, similarly to the fifth embodiment, the time constant of the low-pass filter 51aB can be made variable. FIG. 20 is a block diagram showing a configuration of a harmonic current detection unit 50C in which the time constant of the low-pass filter 51aB is variable. The time constant table 54C stores the time constant of the low-pass filter 51aC corresponding to the u-phase current command value iu * and the v-phase current command value iv *. By making the time constant of the low-pass filter 51aC variable, the fifth
The same effect as when the time constant of the low-pass filter 51aA is variable in the embodiment can be obtained. The time constant of the low-pass filter 51aC stored in the time constant table 54C may be a value corresponding to the U-phase current iu and the V-phase current iv instead of the current command values iu * and iv *.

According to the motor control device of the sixth embodiment, the same effects as those of the motor control device of the fifth embodiment can be obtained.

<< Seventh Embodiment >> FIG. 21 is a diagram showing a configuration of a motor control device according to a seventh embodiment. Seventh
The motor control device according to the third embodiment is configured by replacing the high-pass filter 9 in the motor control device according to the third embodiment with a harmonic current detection unit 50D. Further, a dq / αβ conversion unit 56 is provided to input the current command values iα * and iβ * to the harmonic current detection unit 50D.

FIG. 22 is a block diagram showing the configuration of the harmonic current detector 50D. The current command values iα * and iβ * converted by the dq / αβ conversion unit 56 are input to the low-pass filter 51aD. The input current command value iα *,
iβ * is subjected to a filtering process by a low-pass filter 51aD to obtain current response predicted values iα_i and iβ_i. The subtractor 52 subtracts the predicted α-axis current response value iα_i from the α-axis current iα to obtain a harmonic component iα_h of the α-axis current. Further, the subtractor 53 subtracts the β-axis current response predicted value iβ_i from the β-axis current iβ to obtain a harmonic component i of the β-axis current.
Find β_h. The obtained harmonic components iβ_h and iβ_h are output to the αβ / dhqh conversion unit 35, respectively.

The time constant of the low-pass filter 51aD can be made variable as in the fifth and sixth embodiments. FIG. 23 is a block diagram showing a configuration of a harmonic current detection unit 50E in which the time constant of the low-pass filter 51aD is variable. The time constant table 54E stores the time constant of the low-pass filter 51aE corresponding to the specified α-axis current value iα * and the specified β-axis current value iβ *. The effect of making the time constant of the low-pass filter 51aE variable is the effect of the low-pass filter 51aE in the fifth and sixth embodiments.
This is the same as when the time constant of aA is variable, and the details are omitted.

In the motor control device according to the seventh embodiment, the same effects as those of the motor control devices according to the fifth and sixth embodiments can be obtained.

<< Eighth Embodiment >> A motor control device according to an eighth embodiment differs from the motor control device according to the fourth embodiment in that the high-pass filter 9 is replaced by the harmonic current detector 50.
It is configured by replacing That is, the motor control device of the eighth embodiment includes two sets of harmonic current control circuits of the motor control device of the first embodiment shown in FIG.
FIG. 24 shows the configuration of the motor control device according to the eighth embodiment. As the harmonic current detector 50 can be the same as the harmonic current detector 50 of the first embodiment, the configuration is as shown in FIGS. Also,
The configuration of the harmonic current detector 50 when the time constant of the low-pass filter 51a is made variable is as shown in FIG. In the motor control device according to the eighth embodiment, the same effects as those of the motor control devices according to the fifth to seventh embodiments can be obtained.

The motor control device according to the eighth embodiment has a configuration in which two sets of harmonic control circuits of the motor control device according to the fifth embodiment are provided. Similarly, a configuration in which two sets of harmonic control circuits of the motor control device of the sixth embodiment are provided, or a configuration in which two sets of harmonic control circuits of the motor control device of the seventh embodiment are provided. It can also be. In the motor control device having these configurations, 2
Although it is possible to reduce harmonic components of three orders, it is also possible to adopt a configuration in which three or more harmonic components are reduced.
In this case, the above-described harmonic current control circuits may be provided by the number of harmonic components to be reduced.

The present invention is not limited to the above embodiment. For example, the order of the harmonic current component to be controlled in the harmonic current control circuit of the motor control device of the second to fourth embodiments depends on the control state of the motor such as the motor speed and the load applied to the motor. You can switch. Further, the present invention is not limited to the type of AC motor, and can be applied to a synchronous motor or an induction motor.

[Brief description of the drawings]

FIG. 1 is a diagram illustrating a configuration of a motor control device according to a first embodiment.

FIG. 2 is a diagram illustrating a configuration of a motor control device according to a second embodiment.

FIG. 3 is a diagram illustrating a configuration of a motor control device according to a third embodiment.

FIG. 4 is a diagram illustrating a configuration of a motor control device according to a fourth embodiment.

FIG. 5 is a diagram showing a current waveform of a motor driven by a conventional motor control device.

FIG. 6 is a diagram showing a current waveform of a motor driven according to the first embodiment.

FIG. 7 is a diagram showing a rotor structure of an IPM motor.

FIG. 8 is a diagram showing a rotor structure of the SPM motor.

FIG. 9 is a diagram illustrating a configuration of a motor control device according to a fifth embodiment.

FIG. 10 is a block diagram illustrating a configuration of a harmonic current detector in a motor control device according to a fifth embodiment.

FIG. 11 is a block diagram illustrating a configuration of a harmonic current detection unit configured using a low-pass filter in a current response prediction unit.

FIG. 12 is a block diagram illustrating a configuration of a harmonic current detection unit when a time constant of a low-pass filter is variable.

FIG. 13 is a diagram showing a current command value on the dq axes.

FIG. 14 is a diagram showing q-axis harmonic currents detected by the motor control device according to the first embodiment with respect to the current command values shown in FIG.

FIG. 15 is a diagram showing a q-axis harmonic current detected by the motor control device according to the fifth embodiment with respect to the current command value shown in FIG.

16 is a diagram showing a current response value on the dq axes with respect to the current command value shown in FIG.

FIG. 17 is an enlarged view of a part of FIG. 16;

FIG. 18 is a diagram illustrating a configuration of a motor control device according to a sixth embodiment.

FIG. 19 is a block diagram illustrating a configuration of a harmonic current detector in a motor control device according to a sixth embodiment.

FIG. 20 is a block diagram illustrating a configuration of a harmonic current detector according to a sixth embodiment when the time constant of the low-pass filter is variable.

FIG. 21 is a diagram illustrating a configuration of a motor control device according to a seventh embodiment.

FIG. 22 is a block diagram illustrating a configuration of a harmonic current detection unit in a motor control device according to a seventh embodiment.

FIG. 23 is a block diagram illustrating a configuration of a harmonic current detector according to a seventh embodiment when the time constant of the low-pass filter is variable.

FIG. 24 is a diagram illustrating a configuration of a motor control device according to an eighth embodiment.

FIG. 25 is a diagram showing a configuration of a conventional motor control device.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 Torque control part 2 Fundamental wave current control part 3 dq / 3 phase conversion part 4 Power conversion part 5 Phase speed calculation part 6,7 Current sensor 8 Three phase / dq conversion part 9 High pass filter 10 dq / dhqh conversion part 10A dq / Dh1qh1 converter 10B dq / dh2qh2 converter 11 harmonic current controller 12 dhqh / dq converter 12A dh1qh1 / dq converter 12B dh2qh2 / dq converter 13,14 adder 21 three-phase / dhqh converter 22h Phase converter 31 dq / αβ converter 32 αβ / 3-phase converter 33 3-phase / αβ converter 34 αβ / dq converter 35 αβ / dhqh converter 36 dhqh / αβ converter 50, 50A, 50B, 50C, 50D , 50E harmonic current detector 51 current response predictor 51a, 51aA, 51aB, 51aC, 51aD, 5
1aE, low-pass filter 52, 53 subtractor 54, 54C, 54E time constant table 55 dq / 3-phase converter 56 dq / αβ converter M 3-phase AC motor PS encoder

 ──────────────────────────────────────────────────続 き Continued on the front page (72) Inventor Koichiro Yonekura 2 Takaracho, Kanagawa-ku, Yokohama, Kanagawa Prefecture Inside Nissan Motor Co., Ltd. (72) Inventor Masahiro Tsukamoto 2 Takaracho, Kanagawa-ku, Yokohama City, Kanagawa Nissan Motor Co., Ltd. Terms (reference) 5H560 BB04 BB12 DA07 DB20 DC12 RR01 XA02 XA13 5H576 BB04 DD07 EE01 GG04 JJ17 JJ25 LL07 LL22

Claims (13)

[Claims] 1. A dq coordinate system comprising a d-axis corresponding to an exciting current component of a current flowing through a three-phase AC motor and a q-axis corresponding to a torque current component, and rotating in synchronization with motor rotation. A fundamental wave current control circuit for controlling a wave component, and a harmonic component included in the motor current in an orthogonal coordinate system (hereinafter referred to as a harmonic coordinate system) rotating at an integer multiple of the frequency of the fundamental wave component of the motor current. A harmonic current control circuit for controlling the output of the fundamental current control circuit and the output of the harmonic current control circuit to generate a voltage command value of each phase of the three-phase AC coordinate system, A motor control device for driving and controlling a three-phase AC motor. 2. The motor control device according to claim 1, wherein the harmonic coordinate system rotates at a frequency of a harmonic component of a predetermined order generated when the motor current is controlled only by the fundamental current control circuit. A motor having a rectangular coordinate system, wherein the harmonic current control circuit controls the harmonic current so that the harmonic component of the predetermined order among the harmonic components included in the motor current becomes zero. apparatus. 3. The motor control device according to claim 2, wherein the harmonic current control circuit converts the motor current into a current in a dq coordinate system and detects a harmonic component of the current in the dq coordinate system. A motor control device for converting into a harmonic current in the harmonic coordinate system. 4. The motor control device according to claim 2, wherein the harmonic current control circuit detects a harmonic component of the motor current and converts it into a harmonic current in the harmonic coordinate system. Motor control device. 5. The motor control device according to claim 2, wherein the harmonic current control circuit converts the motor current into a current in an αβ orthogonal coordinate system fixed on a stator side of the motor,
A motor control device, wherein a harmonic component of the current in the αβ coordinate system is detected and converted to a harmonic current in the harmonic coordinate system. 6. The motor control device according to claim 1, wherein a harmonic order to be controlled in the harmonic current control circuit is switched according to a driving state of the motor. Motor control device. 7. The motor control device according to claim 3, wherein the harmonic current control circuit predicts a current response value to a current command value in a dq coordinate system, and a current response value in a dq coordinate system. A motor control device comprising: a harmonic current detection circuit that detects a harmonic current by subtracting a current response value predicted by the current response value prediction circuit from a value. 8. The motor control device according to claim 4, wherein said harmonic current control circuit predicts a current response value to a motor current command value, and said current response value is calculated from a fundamental wave current value. A motor control device comprising: a harmonic current detection circuit that detects a harmonic current by subtracting a current response value predicted by a value prediction circuit. 9. The motor control device according to claim 5, wherein the harmonic current control circuit predicts a current response value to a current command value in an αβ coordinate system, and a current response value in an αβ coordinate system. A motor control device comprising: a harmonic current detection circuit that detects a harmonic current by subtracting a current response value predicted by the current response value prediction circuit from a value. 10. The motor control device according to claim 7, wherein said current response value prediction circuit is a low-pass filter. 11. The motor control device according to claim 10, wherein the time constant of the low-pass filter changes as the state of the motor changes. 12. The motor control device according to claim 1, further comprising a plurality of sets of said harmonic current control circuits corresponding to a plurality of harmonic currents of a plurality of orders. Control device. 13. The motor control device according to claim 12, wherein the harmonic order to be controlled in the harmonic current control circuit is determined in the order of higher harmonic components included in the motor current. Control device.