阅读说明：本技术 电机控制装置和电机控制方法 (Motor control device and motor control method ) 是由 福田健二 于 2018-06-29 设计创作，主要内容包括：提供能以高响应性进行矩形波控制下的电机的驱动电流的偏移或振幅不平衡的校正的电机控制装置和电机控制方法。该电机控制装置和电机控制方法在进行矩形波控制时,对d轴反馈电流(Id)、q轴反馈电流(Iq)进行平滑处理而生成推定d轴电流指令(Id<Sup>*</Sup>)、推定q轴电流指令(Iq<Sup>*</Sup>),并且将其减去d轴反馈电流(Id)、q轴反馈电流(Iq),生成作为变动成分的d轴校正电流(ΔId)、q轴校正电流(ΔIq)。然后,在根据该d轴校正电流(ΔId)、q轴校正电流(ΔIq)生成d轴校正电压(ΔVd)、q轴校正电压(ΔVq)后,将d轴电压指令(Vd)、q轴电压指令(Vq)分别加上d轴校正电压(ΔVd)、q轴校正电压(ΔVq),从而校正电机的驱动电流的偏移或振幅不平衡。因此,能通过d轴反馈电流(Id)、q轴反馈电流(Iq)的瞬时值来进行电机的驱动电流的偏移或振幅不平衡的校正。(Provided are a motor control device and a motor control method which can correct a deviation of a drive current or an amplitude imbalance of a motor under rectangular wave control with high responsiveness. The motor control device and the motor control method smooth d-axis feedback current (Id) and q-axis feedback current (Iq) to generate estimated d-axis current command (Id) when rectangular wave control is performed * ) And estimating a q-axis current command (Iq) * ) Then, the d-axis feedback current (Id) and the q-axis feedback current (Iq) are subtracted therefrom to generate a d-axis correction current (Δ Id) and a q-axis correction current (Δ Iq) as fluctuation components. Then, a d-axis correction voltage (Δ Vd) and a q-axis correction voltage (Δ Vq) are generated from the d-axis correction current (Δ Id) and the q-axis correction current (Δ Iq), and then the d-axis correction voltage (Δ Vd) and the q-axis correction voltage (q) are added to the d-axis voltage command (Vd) and the q-axis voltage command (Vq), respectively(Δ Vq) to correct an offset or amplitude imbalance of the drive current of the motor. Therefore, the offset or the amplitude imbalance of the drive current of the motor can be corrected by the instantaneous values of the d-axis feedback current (Id) and the q-axis feedback current (Iq).)

1. A motor control device has:

an inverter that outputs a 3-phase alternating drive current to the PM motor;

a drive current detection unit that obtains a value of the drive current;

an angle detection unit that acquires an electrical angle of the PM motor;

a 3-phase/dq conversion unit that converts the drive current acquired by the drive current detection unit into a d-axis feedback current and a q-axis feedback current based on the electrical angle;

a torque control unit that outputs a voltage phase based on a torque command value when rectangular wave control is performed;

a voltage command generation unit that generates a d-axis voltage command and a q-axis voltage command based on the voltage phase; and

a control signal generation unit that generates a drive signal for switching the inverter based on a d-axis voltage command and a q-axis voltage command, the motor control device comprising:

a smoothing unit configured to smooth the d-axis feedback current and the q-axis feedback current to generate an estimated d-axis current command and an estimated q-axis current command, respectively;

a correction current generation unit that subtracts the d-axis feedback current and the q-axis feedback current from the estimated d-axis current command and the estimated q-axis current command, respectively, to generate a d-axis correction current and a q-axis correction current, respectively;

a correction voltage generating unit that generates a d-axis correction voltage and a q-axis correction voltage from the d-axis correction current and the q-axis correction current; and

and a voltage command correction unit that adds the d-axis correction voltage and the q-axis correction voltage to the d-axis voltage command and the q-axis voltage command, respectively, and outputs the resultant to the control signal generation unit.

2. A motor control method, comprising:

a drive current acquisition step of acquiring a value of a 3-phase alternating-current drive current output from the inverter to the PM motor;

an electrical angle acquisition step of acquiring an electrical angle of the PM motor;

a feedback current generation step of converting the drive current into a d-axis feedback current and a q-axis feedback current;

a voltage phase generation step of generating a voltage phase based on a torque command value when rectangular wave control is performed;

a dq voltage command generation step of generating a d-axis voltage command and a q-axis voltage command based on the voltage phase;

a current command generation step of smoothing the d-axis feedback current and the q-axis feedback current to generate an estimated d-axis current command and an estimated q-axis current command, respectively;

a correction current generation step of subtracting the d-axis feedback current and the q-axis feedback current from the estimated d-axis current command and the estimated q-axis current command, respectively, to generate a d-axis correction current and a q-axis correction current, respectively;

a correction voltage generation step of generating a d-axis correction voltage and a q-axis correction voltage from the d-axis correction current and the q-axis correction current;

a correction step of adding the d-axis correction voltage and the q-axis correction voltage to the d-axis voltage command and the q-axis voltage command, respectively;

a drive signal generation step of generating a drive signal based on the d-axis voltage command and the q-axis voltage command corrected in the correction step; and

and a driving step of switching the inverter by the driving signal to output a driving current.

Technical Field

The present invention particularly relates to a motor control device and a motor control method for correcting a deviation or the like of a drive current of a motor in rectangular wave control.

Background

Electric motors are used as a power source for many household or mechanical appliances. Among them, a pm (permanent magnet) motor (permanent magnet motor) in which a permanent magnet is provided on a rotor side, an armature winding is provided on a stator side, and a rotor is rotated by controlling a magnetic field of the armature winding has no excitation loss, and therefore, is low-loss and high-efficiency, and is widely used in large-sized machines with a recent trend toward energy saving. In general, this PM motor control method is performed by generating predetermined drive signals Su, Sv, and Sw based on a torque command value instructed from the outside (a higher-level control unit of the system, etc.) and a current torque T of the PM motor, switching the inverter by the drive signals Su, Sv, and Sw, and outputting 3-phase ac drive currents Iu, Iv, and Iw. In many cases, the drive signals Su, Sv, and Sw are generated by switching between sine wave control and rectangular wave control according to the operating conditions of the PM motor. In this control method, the PM motor is controlled (the drive signals Su, Sv, Sw are generated) by sine wave control (PWM control) in the operating region of the middle/low speed rotation, and controlled by rectangular wave control capable of high output in the operating region of the high speed rotation and high torque. However, in both the case of the sine wave control and the case of the rectangular wave control, information on the feedback currents of the drive currents Iu, Iv, Iw of the motors output by the inverters and information on the electrical angles of the PM motors are required for the control of the PM motors.

However, the drive currents Iu, Iv, and Iw may be offset due to the accuracy of an angle sensor for obtaining an electrical angle, a response difference of a switching element of an inverter, and the offset may be an important factor for generating vibration of a motor, torque reduction, loss, and the like. In particular, since the voltage phase is generally used to directly control the torque of the motor in the rectangular wave control, a correction process for an offset component in the feedback current is not performed, and the influence of the offset tends to be significant.

Fig. 4 shows a simulation graph of the three-phase drive currents Iu, Iv, and Iw and the d-axis current and the q-axis current obtained by performing 3-phase/dq conversion on the three-phase drive currents Iu, Iv, and Iw. Fig. 4 (a) is a simulated graph of the driving currents Iu, Iv, and Iw in the case where the amplitudes are unbalanced, and fig. 4 (b) is a simulated graph of the d-axis current and the q-axis current obtained by performing 3-phase/dq conversion on the driving currents Iu, Iv, and Iw. Fig. 4 (c) is a simulated coordinate diagram of the drive currents Iu, Iv, and Iw in the case where there is an offset, and fig. 4 (d) is a simulated coordinate diagram of the d-axis current and the q-axis current obtained by performing 3-phase/dq conversion on the drive currents Iu, Iv, and Iw.

First, as shown by the broken lines in fig. 4 (b) and (d), when there is no amplitude imbalance or offset in the drive currents Iu, Iv, and Iw, the d-axis current and the q-axis current show fixed values. However, when the drive currents Iu, Iv, and Iw have an unbalanced or offset amplitude, the d-axis current and the q-axis current have variations shown by solid lines in fig. 4 (b) and (d). Therefore, it is considered effective to correct or remove the fluctuation component and smooth it in order to suppress the offset or the amplitude imbalance.

Regarding this problem, the following invention is disclosed in the following [ patent document 1 ]: the offset of each phase is calculated by an average value or a low-pass filter in 1 cycle of the drive current Iu, Iv, Iw, and the drive signal is corrected to correct the offset.

Disclosure of Invention

Problems to be solved by the invention

However, the invention described in [ patent document 1] requires an average value of the driving currents Iu, Iv, and Iw of three-phase alternating current in 1 cycle, and therefore, a time is required for calculating the offset amount, and there is a problem of poor responsiveness. Further, in the configuration in which the offset amount is calculated using the low-pass filter described in [ patent document 1], there is a problem that delay may occur in offset correction every time the operating state of the motor changes, and this also causes poor responsiveness. Further, since the offset amount is calculated for each of the 3 phases and offset correction is performed individually, correction for a certain phase may have an adverse effect on the other phases. In addition, the method of calculating the correction amount using the average value or the low-pass filter has a problem that the amplitude imbalance between the three phases cannot be detected and the correction cannot be performed.

The present invention has been made in view of the above circumstances, and an object thereof is to provide a motor control device and a motor control method capable of correcting a deviation or an amplitude imbalance under rectangular wave control with high responsiveness.

Means for solving the problems

The invention

(1) The above problem is solved by providing a motor control device 100, and the motor control device 100 includes:

an inverter 20 that outputs 3-phase ac drive currents Iu, Iv, and Iw to the PM motor 10;

drive current detection units 12u and 12v that acquire values of the drive currents Iu, Iv, and Iw;

an angle detection unit 14 that acquires an electrical angle θ of the PM machine 10;

a 3-phase/dq conversion unit 22 that converts the drive currents Iu, Iv, and Iw acquired by the drive current detection units 12u and 12v into d-axis feedback currents Id and q-axis feedback currents Iq based on the electrical angle θ;

a torque control unit 502 for outputting a control signal based on a torque command value T during rectangular wave control ^*Voltage phase θ v;

a voltage command generation unit 516 that generates a d-axis voltage command Vd and a q-axis voltage command Vq based on the voltage phase θ v; and

a control signal generation unit 30 that generates drive signals Su, Sv, and Sw for switching the inverter 20 based on a d-axis voltage command and a q-axis voltage command, and the motor control device 100 includes:

a smoothing unit 72 for smoothing the d-axis feedback current Id and the q-axis feedback current Iq to generate an estimated d-axis current command Id ^*And an estimated q-axis current command Iq ^*；

A correction current generation unit 74 for generating the correction current from the estimated d-axis current command Id ^*And an estimated q-axis current command Iq ^*Subtracting the d-axis feedback current Id and the q-axis feedback current Iq to generate a d-axis correction current Δ Id and a q-axis correction current Δ Iq, respectively;

a correction voltage generating unit 76 that generates a d-axis correction voltage Δ Vd and a q-axis correction voltage Δ Vq from the d-axis correction current Δ Id and the q-axis correction current Δ Iq; and

and a voltage command correction unit 78 that adds the d-axis correction voltage Δ Vd and the q-axis correction voltage Δ Vq to the d-axis voltage command Vd and the q-axis voltage command Vq, respectively, and outputs the resultant to the control signal generation unit 30.

(2) The above problem is solved by providing a motor control method comprising:

a drive current acquisition step of acquiring values of 3-phase ac drive currents Iu, Iv, and (Iw) output from the inverter 20 to the PM motor 10;

an electrical angle acquisition step of acquiring an electrical angle θ of the PM machine 10;

a feedback current generation step of converting the drive currents Iu, Iv, and Iw into a d-axis feedback current Id and a q-axis feedback current Iq;

a voltage phase generation step of generating a voltage based on the torque command value T during rectangular wave control ^*Voltage phase θ v;

a dq voltage command generation step of generating a d-axis voltage command Vd and a q-axis voltage command Vq based on the voltage phase θ v;

a current command generation step of smoothing the d-axis feedback current Id and the q-axis feedback current Iq to generate an estimated d-axis current command Id ^*And an estimated q-axis current command Iq ^*；

A correction current generation step of estimating the d-axis current command Id from the above ^*And an estimated q-axis current command Iq ^*Subtracting the d-axis feedback current Id and the q-axis feedback current Iq to generate a d-axis correction current Δ Id and a q-axis correction current Δ Iq, respectively;

a correction voltage generation step of generating a d-axis correction voltage Δ Vd and a q-axis correction voltage Δ Vq from the d-axis correction current Δ Id and the q-axis correction current Δ Iq;

a correction step of adding the d-axis correction voltage Δ Vd and the q-axis correction voltage Δ Vq to the d-axis voltage command Vd and the q-axis voltage command Vq, respectively;

a drive signal generation step of generating drive signals Su, Sv, Sw based on the d-axis voltage command Vd 'and the q-axis voltage command Vq' corrected in the correction step; and

and a driving step of switching the inverter 20 by the driving signals Su, Sv, and Sw to output driving currents Iu, Iv, and Iw.

Effects of the invention

A motor control device and a motor control method according to the present invention smooth a d-axis feedback current and a q-axis feedback current to generate an estimated d-axis current command and an estimated q-axis current command when rectangular wave control is performed, and correct the fluctuation component of the d-axis current and the fluctuation component of the q-axis current using the estimated d-axis current command and the estimated q-axis current command. Therefore, it is possible to correct the deviation of the drive current of the motor or the amplitude imbalance in the rectangular wave control with excellent responsiveness. Further, since the motor control device and the motor control method according to the present invention perform the correction in the dq two-phase state, the correction for a certain phase does not adversely affect the other phases.

Drawings

Fig. 1 is a block diagram of a motor control device of the present invention.

Fig. 2 is a diagram illustrating a positional relationship between a triangular wave and a voltage command Vu in the motor control device of the present invention.

Fig. 3 is a graph showing the effects of the motor control device and the control method of the present invention.

Fig. 4 is a diagram illustrating the offset and amplitude imbalance of the 3-phase current and the fluctuation component of the dq-axis current.

Detailed Description

Embodiments of a motor control device 100 and a motor control method according to the present invention are described with reference to the drawings. Here, fig. 1 is a block diagram of a motor control device 100 of the present invention. First, a motor control device 100 according to the present invention controls an operation of a PM motor (permanent magnet motor) 10, and includes: an inverter 20 that outputs 3-phase ac drive currents Iu, Iv, and Iw to the PM motor 10; drive current detection units 12u and 12v for acquiring values of the drive currents Iu, Iv, and Iw; an angle detection unit 14 that acquires an electrical angle θ of the PM motor 10; a 3-phase/dq conversion unit 22 that converts the drive currents Iu, Iv, and Iw acquired by the drive current detection units 12u and 12v into d-axis feedback currents Id and q-axis feedback currents Iq; a sine wave control part 40 and a rectangular wave control part 50 which output a torque command value T instructed from the outside (a higher-level control part of the system, etc.) ^*Corresponding d-axis voltage commands Vd ', q-axis voltage commands Vq'; a control signal generation unit 30 that generates drive signals Su, Sv, Sw for the inverter 20 based on the d-axis voltage command Vd 'and the q-axis voltage command Vq'; and a switching unit 24 that switches control of the PM motor 10 between the rectangular wave control unit 50 and the sinusoidal wave control unit 40 according to the operating state of the PM motor 10.

As described above, the PM machine 10 is configured such that the permanent magnet is provided on the rotor side, the 3-phase armature windings are provided on the stator side, and the 3-phase armature windings are supplied with the ac drive currents Iu, Iv, and Iw, respectively, so that the magnetic poles and magnetic fluxes of the armature windings are continuously changed to rotate the rotor. As the PM machine 10, an IPM machine (Interior Permanent Magnet machine) in which Permanent magnets are embedded in a rotor is preferably used.

As the angle detection unit 14, a known angle sensor capable of acquiring the angle of the rotor can be used. Further, the angle detection unit 14 may acquire the mechanical angle of the rotor and calculate the electrical angle θ by calculation or the like based on the mechanical angle, but it is preferable to directly acquire the electrical angle θ of the PM motor 10 by using a resolver rotation angle sensor having the same number of rotor poles as the number of pole pairs of the permanent magnet in the rotor.

The drive current detection units 12u and 12v may use known current sensors that can obtain the drive currents Iu, Iv, and Iw output from the inverter 20 in a non-contact manner. In this example, 2 driving currents Iu and Iv among the driving currents Iu, Iv and Iw are obtained and converted into d-axis feedback currents Id and q-axis feedback currents Iq. It is preferable that the electric angle θ and the drive currents Iu and Iv be obtained at two timings, i.e., the peak and the trough of a triangular wave to be described later, and be used by each unit of the motor control device 100 to be described later, for each half cycle of the triangular wave.

Next, the configuration and operation of each part of motor control device 100 according to the present invention and the motor control method according to the present invention will be described. First, the inverter 20 turns on and off the internal switching elements in accordance with the drive signals Su, Sv, and Sw output from the control signal generation unit 30, and causes ac drive currents Iu, Iv, and Iw, which are shifted in phase by 1/3 cycles (2/3 pi (rad)), to flow through the armature winding of the PM motor 10. As a result, the magnetic poles and magnetic flux of the armature winding of the PM machine 10 continuously change to generate a rotating magnetic field. Then, the rotor is rotated by an attractive force and a repulsive force with respect to the rotating magnetic field.

At this time, the drive current detection units 12u and 12v acquire values of the drive currents Iu and Iv output from the inverter 20, and output the values to the 3-phase/dq conversion unit 22 (drive current acquisition step). The angle detection unit 14 acquires the electrical angle θ (rad) of the PM motor 10 and outputs the same to the 3-phase/dq conversion unit 22 (electrical angle acquisition step). Thus, the 3-phase/dq conversion unit 22 performs 3-phase 2-phase conversion and rotation coordinate conversion for the drive currents Iu, Iv, and Iw based on the electrical angle θ of the PM motor 10, and converts the drive currents Iu, Iv, and Iw into a d-axis current (magnetic flux partial current) Id and a q-axis current (torque partial current) Iq (feedback current generation step). Then, the d-axis current (magnetic flux partial current) Id and the q-axis current (torque partial current) Iq are output to the switching unit 24 as d-axis feedback current Id and q-axis feedback current Iq.

The electrical angle θ acquired by the angle detection unit 14 is also output to the angular velocity calculation unit 16, and the angular velocity calculation unit 16 calculates the electrical angular velocity ω (rad/s) from the input electrical angle θ and outputs the electrical angular velocity ω to each unit.

The switching unit 24 is a switching circuit that switches the method of generating the d-axis voltage command Vd 'and the q-axis voltage command Vq' according to the operating conditions of the PM motor 10, and switches the generation of the d-axis voltage command Vd 'and the q-axis voltage command Vq' from the sine wave control unit 40 to the rectangular wave control unit 50 when the PM motor 10 operates in a predetermined high rotation speed and high torque operation region. Thus, the PM motor 10 is controlled by sine wave control with little torque variation during the middle/low speed rotation operation, and by rectangular wave control with high output during the high speed rotation/high torque operation.

Next, the configuration and operation of the sine wave control unit 40 will be described. The configuration of the sine wave control unit 40 described below is a preferred example of the present invention, and therefore, the present invention is not limited to the following configuration, and other arbitrary sine wave control means may be used.

First, a torque command value T is output from a control unit or the like of the upper system ^*. The torque command value T ^*Is the torque of the PM machine 10 as the operation target. The torque command value T ^*When the sine wave control unit 40 is selected by the switching unit 24, the selected sine wave control unit is input to the torque control unit 402 of the sine wave control unit 40. The current torque T of the PM machine 10 is input from the torque calculation unit 404 to the torque control unit 402.

Here, the torque calculation unit 404 has an induced voltage constant as a motor parameter of the PM motor 10

d-axis inductance Ld, q-axis inductance Lq, and the like. In addition, induced voltage constant

The d-axis inductance Ld and the q-axis inductance Lq may be fixed values set in advance, or may be obtained appropriately from, for example, a data table or the like according to the temperature or the operating condition of the PM motor 10A predetermined appropriate value. The torque calculation unit 404 then calculates the d-axis feedback current Id and the q-axis feedback current Iq based on these values, or the d-axis current command Id output from the current command generation unit 406 ^*Q-axis current command Iq ^*And calculates the current torque T of the PM machine 10 based on, for example, the following equation. In this example, the d-axis current command Id is shown ^*Q-axis current command Iq ^*An example of the torque T is calculated.

P: pole pair number of permanent magnet of PM motor

Constant of induced voltage

And Ld: d-axis inductor

And (Lq): q-axis inductor

Torque control unit 402 then controls torque command value T ^*And current torque T sets current command value Ia for operating PM motor 10 at the target torque ^*And outputs the result to the current command generation unit 406. Further, the current command value Ia ^*It may be calculated by calculation such as integral control and proportional control.

The current command generation unit 406 has motor parameters similar to those of the torque calculation unit 404, and receives the electric angular velocity ω from the angular velocity calculation unit 16 and the power supply voltage Vdc from a power supply unit, not shown, as input thereto. Then, current command generation unit 406 uses current command value Ia from torque control unit 402 ^*A d-axis current command Id is calculated by predetermined calculation or voltage control of the power supply voltage Vd, the motor parameter, and the electrical angular velocity ω ^*Q-axis current command Iq ^*And outputs the result to the voltage command generation unit 416 of the sine wave control unit 40. In addition, at this time, the d-axis current command Id is adjusted ^*Q-axis current command Iq ^*The voltage command is set so that the magnitude | Va | of the voltage command does not exceed the value of K × Vdc (K: voltage utilization rate set value), and the sinusoidal wave control region and the rectangular wave control region can be controlled by the voltage commandBy providing an overmodulation control region between the control regions, the output in the medium-high speed operation region can be improved. Further, the current command value Ia may be set as necessary ^*D-axis current command Id ^*Q-axis current command Iq ^*A current limiter is provided.

Here, a preferred example of the voltage command value generation unit 416 will be described. First, the d-axis current command value Id input to the voltage command value generation unit 416 ^*Q-axis current command value Iq ^*The branch is divided into two parts, and one of them is inputted to the non-interference control section 414. Then, the non-interference control unit 414 calculates the d-axis current command value Id ^*Q-axis current command value Iq ^*The speed electromotive force component causing the interference is output to current control unit 410 as d-axis voltage command Vd ″ and q-axis voltage command Vq ″. In addition, the d-axis current command Id ^*Q-axis current command Iq ^*The other of the d-axis feedback current Id and the q-axis feedback current Iq is subtracted by the subtraction unit 412 to become fluctuation components Δ Id and Δ Iq, and then input to the current control unit 410. Then, the current control unit 410 appropriately performs current control such as current integration control and current ratio control, and adds the d-axis voltage command Vd ″ and the q-axis voltage command Vq ″ from the non-interference control unit 414 at appropriate positions to generate a d-axis voltage command Vd 'and a q-axis voltage command Vq'. Then, the current control by the current control unit 410 reduces or smoothes the fluctuation component of the d-axis current command and the fluctuation component of the q-axis current command (the offset or the amplitude imbalance component of the drive currents Iu, Iv, Iw).

It is preferable that the voltage command generation unit 416 be provided with a limiter unit that limits the voltage commands Vu, Vv, Vw based on the d-axis voltage command Vd 'and the q-axis voltage command Vq' so as not to reach the vicinity of the maximum voltage (voltage of a rectangular wave voltage of 1 pulse) that becomes the output limit of the inverter 20. The limit voltage of the limiter unit is preferably set according to the number of synchronizations of the triangular wave set by the synchronization control unit 420, which will be described later.

Further, the sine wave control unit 40 includes: a polar coordinate conversion unit 418 that obtains the d-axis voltage command Vd '″, q-axis voltage command Vq' ″ of the current control unit 410, performs polar coordinate conversion, and obtains the voltage phase θ v and the magnitude | Va | of the voltage command; and a synchronization control unit 420 that generates carrier setting information Sc of a triangular wave, which will be described later, based on the voltage phase θ v, the electrical angular velocity ω, and the electrical angle θ obtained by the polar coordinate conversion unit 418, and outputs the carrier setting information Sc to the triangular wave generation unit 34. The carrier setting information Sc is described later.

Then, the d-axis voltage command Vd 'and the q-axis voltage command Vq' output from the current control unit 410 are input to the control signal generation unit 30 via the switching unit 24. Here, a preferred example of the control signal generating unit 30 will be described. The configuration of the control signal generating unit 30 described below is a preferred example of the present invention, and therefore, the present invention is not limited to the configuration described below, and other arbitrary control signal generating means may be used.

First, the d-axis voltage command Vd 'and the q-axis voltage command Vq' output from the current control unit 410 are input to the dq/3 phase conversion unit 32 of the control signal generation unit 30. The control signal generating unit 30 may further include a linearity correcting unit 38 at a stage preceding the dq/3 phase converting unit 32, the linearity correcting unit 38 correcting the non-linearity of the d-axis voltage command Vd ', the q-axis voltage command Vq', and the voltage commands Vu, Vv, and Vw during the rectangular wave control and the overmodulation control. The correction value used by the linear correction unit 38 is preferably set in accordance with, for example, the modulation factor or the magnitude | Va | of the voltage command, the rectangular-wave forming voltage | Va' |, and the like.

The electrical angle θ from the angle detection unit 14 and the electrical angular velocity ω from the angular velocity calculation unit 16 are input to the dq/3 phase conversion unit 32, and the dq/3 phase conversion unit 32 calculates a predicted electrical angle θ 'at a new timing at which the inverter 20 performs a switching operation based on the electrical angle θ and the electrical angular velocity ω, converts the d-axis voltage command Vd' and the q-axis voltage command Vq 'into 3-phase voltage commands Vu, Vv, Vw based on the predicted electrical angle θ', and outputs the voltage commands Vu, Vv, Vw to the drive signal generation unit 36.

The drive signal generator 36 includes a triangular wave generator 34, and the carrier setting information Sc is input to the triangular wave generator 34, and the triangular wave generator 34 generates a triangular wave based on the cycle of the carrier setting information Sc.

Then, the drive signal generation unit 36 compares the triangular wave with the voltage commands Vu, Vv, Vw, respectively. At this time, the amplitude of the triangular wave increases or decreases according to carrier setting information Sc described later. Therefore, the voltage commands Vu, Vv, Vw are adjusted by a conversion factor proportional to the amplitude of the triangular wave, and triangular wave comparison is performed using the adjusted voltage commands Vu, Vv, Vw. Thus, the driving signals Su, Sv, Sw of Hi-Low are generated. The drive signals Su, Sv, Sw are output to the inverter 20, and the inverter 20 performs a switching operation based on the drive signals Su, Sv, Sw to output 3-phase ac drive currents Iu, Iv, Iw, thereby operating the PM motor 10.

When the PM motor 10 operates in an operating region of high rotational speed and high torque, the switching unit 24 switches the control of the PM motor 10 from the sinusoidal wave control unit 40 to the rectangular wave control unit 50. Thus, the torque command value T ^*The torque is input to the torque control unit 502 of the rectangular wave control unit 50. The d-axis feedback current Id and the q-axis feedback current Iq are input to the torque calculation unit 504 of the rectangular wave control unit 50. Further, the torque calculation unit 504 has motor parameters in the same manner as the torque calculation unit 404 of the sine wave control unit 40, calculates the current torque T of the PM motor 10 from these motor parameters, the d-axis feedback current Id, and the q-axis feedback current Iq, and outputs the current torque T to the torque control unit 502. Then, torque control unit 502 responds to torque command value T ^*And a torque T, and a voltage phase θ v is generated by integral control, proportional control, or the like so that the PM machine 10 operates at a target torque (voltage phase generation step). Then, the voltage command is output to the voltage command generation unit 516 of the rectangular wave control unit 50 and the synchronization control unit 520.

The synchronization control unit 520 generates carrier setting information Sc for setting a triangular wave used for triangular wave comparison, based on the voltage phase θ v, the electrical angular velocity ω, and the electrical angle θ. And outputs it to the triangular wave generating unit 34. Here, it is preferable that the triangular wave set in the carrier setting information Sc has a frequency that is an integral multiple of 3 of the frequency of the voltage command Vu, Vv, Vw, preferably an odd integral multiple of 3, that is, 9, 15, 21, 27 times, or the like (hereinafter, this multiple is referred to as the synchronization number), and a center position of a falling edge of the triangular wave shown by a point a in fig. 2 intersects a zero point position of a rising edge of the voltage command Vu. The number of synchronizations of the triangular wave is set according to the electrical angular velocity ω. Synchronization control unit 520 sets the period of the triangular wave in which the center position of the triangular wave intersects the zero point position of voltage command Vu based on voltage phase θ v and electrical angle θ, and sets the period of the triangular wave in which the frequency of the triangular wave is equal to the set number of synchronizations. Further, the synchronization control unit 520 changes the setting information of the period in conjunction with the change of the electrical angular velocity ω, and causes the triangular wave to follow and maintain the above state. When the electrical angular velocity ω exceeds a predetermined value set in advance, the synchronization control unit 520 sets the number of synchronizations to be 1 step lower and outputs the carrier setting information Sc. When the electrical angular velocity ω is lower than a predetermined value set in advance, the carrier setting information Sc is set by increasing the number of synchronizations by 1 step and output. It is preferable that the value of the electrical angular velocity ω for changing the number of synchronizations is stored in advance in a data table or the like for each number of synchronizations, and the synchronization control unit 520 acquires and sets the corresponding number of synchronizations from the data table based on the input electrical angular velocity ω. In this case, it is preferable that the electrical angular velocity ω for increasing or decreasing the number of synchronizations has a hysteresis (hysteris) width. The operations of these synchronization control units 520 are basically the same in the synchronization control unit 420. In conjunction with the change in the period of the triangular wave, correction gains (Kd, Kq) of the correction voltage generation unit 76, which will be described later, time constants of the smoothing unit 72, gains of the respective controls, and the like are adjusted and reset.

The synchronization control unit 520 obtains a rectangular wave forming voltage | Va '| such that the triangular wave and the voltage commands Vu, Vv, Vw intersect 2 times in a period of 1 cycle of the voltage commands Vu, Vv, Vw, that is, the drive signals Su, Sv, Sw generated by the triangular wave comparison are rectangular waves of 1 pulse, and outputs the voltage | Va' | to the voltage command generating unit 516. It is preferable that the rectangular wave forming voltage | Va ' | set by the synchronization control unit 520 is such that a value of the rectangular wave forming voltage | Va ' | crossing at 2 points is set in advance in the data table for each synchronization number of the triangular wave, and the synchronization control unit 520 selects and sets the rectangular wave forming voltage | Va ' | corresponding to the synchronization number while determining the synchronization number of the triangular wave. Then, the synchronization control unit 520 outputs the rectangular wave forming voltage | Va' | to the voltage command generation unit 516 and the linear correction unit 38.

The voltage command generation unit 516 generates a d-axis voltage command Vd and a q-axis voltage command Vq based on the voltage phase θ v input from the torque control unit 502 and the rectangular wave forming voltage | Va' | input from the synchronization control unit 520 (dq voltage command generation step).

Here, the rectangular wave control unit 50 of the motor control device 100 of the present invention includes a correction unit 70 as a characteristic configuration of the present invention, and the correction unit 70 includes a smoothing unit 72, a correction current generation unit 74, a correction voltage generation unit 76, and a voltage command correction unit 78.

The smoothing unit 72 of the correction unit 70 performs, for example, moving average processing or smoothing processing on the d-axis feedback current Id and the q-axis feedback current Iq input via the switching unit 24, and smoothes the currents. The smoothing processing here is processing for smoothing the input signals (d-axis feedback current value Id and q-axis feedback current value Iq) by performing processing of the following expression (1) at arbitrary intervals.

C＝B(1-K)+K×A····(1)

Where a is an input value (d-axis feedback current value Id, q-axis feedback current value Iq), B is an output value after smoothing in the immediately preceding cycle, K is a smoothing constant, and C is an output value (estimated d-axis current command value Id) ^*And estimating a q-axis current command value Iq ^*)。

By this smoothing process, a pseudo estimated d-axis current command Id is generated in which a fluctuation component due to offset or the like is smoothed ^*Estimating the q-axis current command Iq ^*(current command generation step). Then, these estimated d-axis current command values Id ^*And estimating a q-axis current command value Iq ^*And outputs the result to the correction current generation unit 74.

The d-axis feedback current Id and the q-axis feedback current Iq are input to the correction current generator 74, and the correction current generator74 from the estimated d-axis current command Id generated by the smoothing unit 72 ^*And an estimated q-axis current command Iq ^*The d-axis feedback current Id and the q-axis feedback current Iq are subtracted, respectively. Thereby, d-axis correction current Δ Id and q-axis correction current Δ Iq as fluctuation components are generated (correction current generation step). Then, the d-axis correction current Δ Id and the q-axis correction current Δ Iq are output to the correction voltage generation unit 76. The d-axis correction current Δ Id and the q-axis correction current Δ Iq are estimated d-axis current commands Id smoothed from a component (fluctuation component) of offset or amplitude imbalance ^*And an estimated q-axis current command Iq ^*The d-axis feedback current Id and the q-axis feedback current Iq each including a component (fluctuation component) of an offset or an amplitude imbalance are subtracted from each other, and therefore, the components are basically in opposite phases to the fluctuation component.

The correction voltage generator 76 generates a d-axis correction voltage Δ Vd and a q-axis correction voltage Δ Vq from the d-axis correction current Δ Id and the q-axis correction current Δ Iq input from the correction current generator 74 by proportional control based on predetermined correction gains (Kd, Kq), for example (correction voltage generation step), and outputs the generated voltages to the voltage command value corrector 78.

The voltage command value correction unit 78 adds the d-axis correction voltage Δ Vd and the q-axis correction voltage Δ Vq input from the correction voltage generation unit 76 to the d-axis voltage command value Vd and the q-axis voltage command value Vq output from the voltage command value generation unit 516, respectively, to generate a d-axis voltage command Vd 'and a q-axis voltage command Vq' (correction step). Here, the d-axis voltage command Vd 'and the q-axis voltage command Vq' are the d-axis correction voltage Δ Vd and the q-axis correction voltage Δ Vq to which the opposite phases of the offset or amplitude imbalance component (fluctuation component) are added, as described above. That is, the d-axis voltage command Vd 'and the q-axis voltage command Vq' are added with voltages (d-axis correction voltage Δ Vd and q-axis correction voltage Δ Vq) opposite to each other in the amount of offset or amplitude imbalance generated in the drive currents Iu, Iv and Iw.

Fig. 3 shows graphs of drive currents Iu, Iv, and Iw in which an offset occurs when the conventional rectangular wave control unit without the correction unit 70 is used, and graphs of drive currents Iu, Iv, and Iw when the rectangular wave control unit 50 with the correction unit 70 is used under the same conditions. Fig. 3 (a) is a graph of the drive currents Iu, Iv, and Iw of the rectangular wave control unit without the correction unit 70, and fig. 3 (b) is a graph of the drive currents Iu, Iv, and Iw of the rectangular wave control unit 50 with the correction unit 70.

As is clear from fig. 3, the drive currents Iu, Iv, Iw of the rectangular wave control unit having no correction unit 70 are shifted from the center positions of the waveforms up and down, and the drive currents Iu, Iv, Iw of the rectangular wave control unit 50 having the correction unit 70 are not shifted from the center positions of the waveforms, so that the shifts are eliminated. This means that the d-axis correction voltage Δ Vd and the q-axis correction voltage Δ Vq are added by the correction unit 70, and the offsets of the drive currents Iu, Iv, and Iw are corrected and eliminated.

Then, these d-axis voltage command Vd 'and q-axis voltage command Vq' are input to the control signal generating unit 30 via the switching unit 24. Further, similarly to the case of the sine wave control unit 40, the voltage commands Vu, Vv, Vw are converted into 3-phase voltage commands Vu, Vv, Vw by the dq/3-phase conversion unit 32 via the linearity correction unit 38.

Then, the drive signal generating unit 36 performs triangular wave comparison to generate drive signals Su, Sv, and Sw (drive signal generating step). The triangular wave at this time is a triangular wave having a frequency that is an integral multiple of 3 of the voltage commands Vu, Vv, Vw, based on the carrier setting information Sc from the synchronization control unit 520.

Then, the inverter 20 is switched by the drive signals Su, Sv, and Sw. Thereby, the driving currents Iu, Iv, Iw of the three-phase alternating current are output to the PM motor 10 (driving step). The PM motor 10 is controlled to match the torque command value T by the drive currents Iu, Iv, Iw ^*The corresponding torque performs a rotational motion. At this time, the d-axis voltage command Vd 'and the q-axis voltage command Vq' which are the basis of the drive currents Iu, Iv, and Iw are corrected for components of offset or amplitude imbalance (fluctuation components) by adding the d-axis correction voltage Δ Vd and the q-axis correction voltage Δ Vq, which are opposite in phase to the fluctuation components, as described above, respectively, so that the offset or amplitude imbalance of the PM motor 10 operated by the drive currents Iu, Iv, and Iw is eliminated, and the rotation operation can be performed with low vibration and high efficiency even in the rectangular wave control.

As described above, the motor control device 100 and the motor control method according to the present invention smooth the d-axis feedback current Id and the q-axis feedback current Iq during rectangular wave control to generate the estimated d-axis current command Id ^*And an estimated q-axis current command Iq ^*And from this estimated d-axis current command Id ^*And an estimated q-axis current command Iq ^*The d-axis feedback current Id and the q-axis feedback current Iq are subtracted to generate a d-axis correction current Δ Id and a q-axis correction current Δ Iq as fluctuation components. Then, a d-axis correction voltage Δ Vd and a q-axis correction voltage Δ Vq are generated from the d-axis correction current Δ Id and the q-axis correction current Δ Iq, and then a d-axis voltage command Vd and a q-axis voltage command Vq output from the voltage command generation unit 516 are added thereto, respectively, to correct the fluctuation component. Therefore, the fluctuation component can be corrected by the instantaneous values of the d-axis feedback current Id and the q-axis feedback current Iq. This makes it possible to correct the offset and the amplitude imbalance of the drive currents Iu, Iv, and Iw of the PM motor 10 during rectangular wave control with extremely high responsiveness. The motor control device 100 and the motor control method according to the present invention perform correction in a dq two-phase state, that is, in a state of the d-axis voltage command Vd 'and the q-axis voltage command Vq'. That is, since the correction is not performed for each phase (U-phase, V-phase, and W-phase) individually, the correction for a certain phase does not adversely affect the other phases.

The configuration, mechanism, order of motor control method, and the like of each part of motor control device 100 shown in this example are examples, and therefore, the present invention is not limited to the above examples, and can be implemented by changing the configuration, mechanism, and order of the motor control method without departing from the spirit of the present invention.

Description of the reference numerals

10: PM motor

12u, 12 v: drive current detection unit

14: angle detecting unit

20: inverter with a voltage regulator

22: 3-phase/dq conversion unit

30: control signal generating part

502: torque control unit

516: voltage command generation unit

72: smooth part

74: correction current generation unit

76: correction voltage generating unit

78: voltage command correction unit

100: motor control device

Iu, Iv, Iw: drive current

Id. Iq: d-axis feedback current and q-axis feedback current

Id ^*、Iq ^*: estimation of d-axis Current Command and estimation of q-axis Current Command (in rectangular wave control)

Δ Id, Δ Iq: d-axis correction current, q-axis correction current (in rectangular wave control)

Vd, Vq: d-axis voltage command, q-axis voltage command (in rectangular wave control)

Δ Vd, Δ Vq: d-axis correction voltage, q-axis correction voltage (in rectangular wave control)

Su, Sv, Sw: drive signal

T ^*: torque command value

θ: electric angle

θ v: the voltage phase.