WO2016084260A1

WO2016084260A1 - Motor control device and motor control method

Info

Publication number: WO2016084260A1
Application number: PCT/JP2014/081652
Authority: WO
Inventors: 高木　護; 森本　進也
Original assignee: 株式会社安川電機
Priority date: 2014-11-28
Filing date: 2014-11-28
Publication date: 2016-06-02

Abstract

A motor control device (1) for controlling the drive of a variable field motor (M) having a variable field mechanism capable of changing field magnetic flux comprises: a voltage command value calculation unit (12) configured so as to calculate a voltage command value (V1); a constant output control unit (13) configured so as to generate a field ratio correction command value (Idc) on the basis of the voltage command value (V1) and an arbitrarily set reference voltage command value (Vref); and a field ratio calculation unit (14) configured so as to calculate a field ratio of the variable field motor (M) on the basis of the field ratio correction command value (Idc).

Description

Motor control device and motor control method

The disclosed embodiment relates to a motor control device and a motor control method.

Patent Document 1 discloses a synchronous motor control method that enables high-speed rotation by field-weakening control.

JP-A-8-9699

On the other hand, a variable magnetic field motor that can expand the output range by having a variable field mechanism that varies the field magnetic flux has been proposed. When this variable magnetic field motor is to be controlled, the field magnetic flux is changed using the magnetic field as a control parameter. The optimum value of this magnetic field is determined by the field state, power supply voltage, torque It is greatly influenced by etc. Even when the motor characteristics change due to a temperature change or the like, the optimum value of the magnetic field factor fluctuates, making it difficult to maintain the optimum control state.

The present invention has been made in view of such a problem, and can appropriately variably control the field magnetic flux of the variable field motor according to field weakening control or temperature change, and cannot drive the variable field motor. It is an object of the present invention to provide a motor control device and a motor control method capable of functionally expanding the output range without reducing the output range.

In order to solve the above problems, according to one aspect of the present invention, a motor control device that controls driving of a variable field motor having a variable field mechanism that varies a field magnetic flux, and calculates a voltage command value. A voltage calculator configured to generate, a constant output controller configured to generate a field factor correction command value based on the voltage command value and an arbitrarily set reference voltage command value, and the field factor A motor control device having a field factor calculation unit configured to calculate a field factor of the variable field motor based on a correction command value is applied.

According to another aspect of the present invention, there is provided a motor control method for controlling driving of a variable field motor having a variable field mechanism that varies a field magnetic flux, calculating a voltage command value, Generating a field factor correction command value based on a voltage command value and an arbitrarily set reference voltage command value; calculating a field factor of the variable field motor based on the field factor correction command value; A motor control method for executing is applied.

According to another aspect of the present invention, there is provided a motor control device that controls driving of a variable field motor having a variable field mechanism that varies a field magnetic flux, and a d-axis voltage command based on a torque command. a means for generating a q-axis voltage command; a means for calculating a voltage command value based on the d-axis voltage command and the q-axis voltage command; and based on the voltage command value and an arbitrarily set reference voltage command value. A motor control device having means for generating a field factor correction command value and means for calculating a field factor of the variable field motor based on the field factor correction command value is applied.

According to another aspect of the present invention, there is provided a motor control device that controls driving of a variable field motor having a variable field mechanism that varies a field magnetic flux, and is configured to calculate a voltage command value. Based on the voltage calculation unit, a constant output control unit configured to generate a field factor correction command value based on the voltage command value and an arbitrarily set reference voltage command value, and the field factor correction command value A field factor calculation unit configured to calculate a field factor of the variable field motor, and the constant output control unit determines a command value deviation between the voltage command value and the reference voltage command value. The field factor correction command value is generated based on the field factor calculation unit, and the field factor calculation unit calculates the field factor by correcting the value calculated by table conversion based on the torque command and the motor speed with the field factor correction command value. Motor control device is applied .

According to another aspect of the present invention, there is provided a motor control method for controlling driving of a variable field motor having a variable field mechanism that varies a field magnetic flux, the step of calculating a voltage command value, Generating a field factor correction command value based on a voltage command value and an arbitrarily set reference voltage command value; calculating a field factor of the variable field motor based on the field factor correction command value; A motor control method for executing is applied.

According to another aspect of the present invention, in the step of generating the field factor correction command value, the field factor correction command value is generated based on a command value deviation between the voltage command value and the reference voltage command value. A motor control method is applied.

According to another aspect of the present invention, in the step of generating the field factor correction command value, a value obtained by limiting a maximum absolute value of the command value deviation by a field factor adjustment Id limiter is set to the field factor correction command value. The motor control method generated as follows is applied.

Further, according to another aspect of the present invention, in the step of calculating the field ratio, a value calculated by table conversion based on a torque command and a motor speed is corrected with the field factor correction command value, and the field factor is calculated. A motor control method for calculating is applied.

Further, according to another aspect of the present invention, in the step of calculating the magnetic field ratio, a motor control method is used in which the field ratio is calculated by correcting the maximum field ratio with the field ratio correction command value. .

According to another aspect of the present invention, in the step of generating the field correction command value, a motor that generates a d-axis current command correction value for correcting a d-axis current command based on the command value deviation. The control method is applied.

Further, according to another aspect of the present invention, in the step of generating the magnetic field correction command value, the positive value of the command value deviation is set to substantially zero and the minimum negative value is limited by the constant output control Id limiter. A motor control method for generating a value as the d-axis current command correction value is applied.

According to another aspect of the present invention, in the step of generating the field factor correction command value, a difference value between the command value deviation and the d-axis current command correction value is generated as the field factor correction command value. A motor control method is applied.

According to the present invention, the field flux of the variable field motor can be appropriately variably controlled according to field weakening control or temperature change, and the output range can be functionally expanded without disabling the variable field motor. it can.

It is a functional block diagram of the motor control device concerning an embodiment. It is an external appearance perspective view of the rotor in the state in which the linkage flux in an example of the variable field motor was weakened. It is an external appearance perspective view of the rotor in the state where the linkage flux in the example of the variable field motor became the strongest. It is a whole axis orthogonal sectional view in an example of a variable field motor. It is a block diagram which shows the internal structure of a constant output control part. It is a flowchart which shows the procedure of a magnetic field factor calculation process. It is a figure which shows an example of a field factor table. It is a block diagram which shows the internal structure of the constant output control part which concerns on a modification. It is a flowchart which shows the procedure of the field factor calculation process which concerns on a modification.

<Basic configuration of the embodiment>
Hereinafter, embodiments will be described with reference to the drawings. FIG. 1 is a functional block diagram of a motor control device according to the present embodiment. In FIG. 1, a high efficiency control unit 2, an Iq command generation unit 3, an ACR 4, a dq / 3 phase conversion unit 5, a PWM conversion unit 6, an inverter 7, a current detection unit 8, a motor M, , Encoder PG, field adjustment mechanism 9, three-phase / dq conversion unit 10, differentiator 11, voltage command value calculation unit 12, constant output control unit 13, field factor calculation unit 14, and adder 19 is shown. Among these components, the components excluding the motor M, the encoder PG, and the field adjustment mechanism 9 constitute the motor control device 1 of the present embodiment. In the example of the present embodiment, the motor control device 1 includes a CPU (not shown), and each component (except for the PWM conversion unit 6 and the inverter 7) of the motor control device 1 shown in FIG. It is realized by software executed by the CPU.

The high efficiency control unit 2 generates a d-axis current command Idref of a d-axis component that greatly affects the excitation of the motor M based on the torque command Tref input from the outside. The d-axis current command Idref is generated so that the maximum torque can be obtained with the minimum current using the magnet torque and the reluctance torque. In this example, the d-axis current command Idref is calculated by a calculation based on the calculation formula. Is generated. The d-axis current command Idref is added to the output of the constant output control unit 13 described later and the adder 19 and then input to the Iq command generation unit 3 and the ACR 4 respectively.

The Iq command generation unit 3 generates a q-axis component q-axis current command Iqref that greatly affects the torque generation of the motor M based on the input d-axis current command Idref. In this example, the q-axis current command Iqref is generated by calculation based on the calculation formula. The q-axis current command Iqref is input to the ACR 4 as it is. Note that, depending on the type of motor M (for example, an IPM motor), the d-axis current command Idref may have some influence on the torque.

The ACR 4 receives the q-axis current command Iqref and the d-axis current command Idref, and also receives a detected q-axis current value Iq and a detected d-axis current value Id from a three-phase / dq converter 10 described later. Corresponding to the axis, it functions as a current control unit that outputs the q-axis voltage command Vqref and the d-axis voltage command Vdref based on the deviation between them. The ACR 4 generates a q-axis voltage command Vqref and a d-axis voltage command Vdref corresponding to the speed change of the motor M by calculation based on the motor speed ω input from the differentiator 11 described later.

The dq / 3-phase conversion unit 5 converts the q-axis voltage command Vqref and the d-axis voltage command Vdref into the U-phase voltage command Vu and the V-phase based on the rotational position θ of the motor M detected from an encoder PG described later. Coordinates are converted into a three-phase voltage command of a voltage command Vv and a W-phase voltage command Vw.

The PWM conversion unit 6 outputs a PWM drive signal corresponding to each phase by PWM conversion based on the comparison between the above three-phase voltage commands Vu, Vv, Vw and a carrier wave (triangular wave) generated internally.

The inverter 7 supplies power to the motor M by converting supply power from an external power source (not shown) into drive power of each phase by PWM control by a switching operation based on the PWM drive signal corresponding to each phase.

The current detector 8 detects the drive current values Iu, Iv, and Iw of the drive power of each phase fed from the inverter 7.

The motor M is a variable field motor provided with a variable field mechanism that varies the field magnetic flux therein, and is driven by the driving power of each phase fed from the inverter 7. A configuration example of the variable field motor including the variable field mechanism will be described in detail later.

The encoder PG is composed of an optical rotary encoder, for example, and detects the rotational position θ of the motor M (hereinafter referred to as motor position θ).

The field adjustment mechanism 9 controls the variable field mechanism in the variable field motor M based on the field factor input from the field factor calculation unit 14 described later, and adjusts the field flux of the variable field motor M. . In the example of the present embodiment, it is assumed that the field adjusting mechanism 9 is configured to adjust the field magnetic flux by a mechanical drive mechanism using a servo motor or the like. A configuration in which the variable field mechanism is controlled by typical driving is also applicable.

The three-phase / dq conversion unit 10 detects the driving current values Iu, Iv, Iw of each phase detected from the current detection unit 8 based on the motor position θ detected from the encoder PG, and detects the q-axis current value Iq. And coordinate conversion into a detected d-axis current value Id. As described above, the ACR 4 includes the q-axis current command Iqref and the d-axis current command Idref based on the torque command Tref, the detected q-axis current value Iq and the detected d-axis current value Id actually input to the motor M. Q-axis voltage command Vqref and d-axis voltage command Vdref are output based on the deviation between the two. Thereby, a feedback loop for current control (torque control) is configured by the ACR 4, the dq / 3-phase converter 5, the PWM converter 6, the inverter 7, the current detector 8, and the 3-phase / dq converter 10. Control is performed so that the current actually input to the motor M follows the value of the torque command Tref. Although not particularly illustrated, the torque command Tref may be directly input from the host control device, or may be further input by providing a feedback loop for speed control and a feedback loop for position control.

Based on the q-axis voltage command Vqref and the d-axis voltage command Vdref output from the ACR 4, the voltage command value calculation unit 12 converts the q-axis component and the d-axis component into a command value of the input voltage to the motor M. The corresponding voltage command value V1 is calculated. The voltage command value calculation unit 12 corresponds to the voltage calculation unit described in each claim.

The differentiator 11 calculates the motor speed ω by performing a first-order differential operation on the motor position θ detected by the encoder PG.

The constant output controller 13 outputs a d-axis current command correction value ΔIdref and a field factor correction command value Idc based on a deviation between the reference voltage command value Vref and the voltage command value V1 input from the outside. By adding the d-axis current command correction value ΔIdref to only the d-axis current command Idref by the adder 19, the d-axis current command Idref is adjusted according to the increase / decrease change of the input voltage when the motor M rotates at high speed. Constant output control that stabilizes the driving of M is possible. That is, a feedback loop for voltage control is configured by the Iq command generation unit 3, the ACR 4, the voltage command value calculation unit 12, and the constant output control unit 13, and the voltage input to the motor M is the value of the reference voltage command value Vref. It controls to follow corresponding to. Further, the field factor correction command value Idc output by the constant output calculator 13 is input to the field factor calculator 14. The internal configuration of the constant output control unit 13 will be described in detail later.

In the example of this embodiment, the field factor calculator 14 first calculates a field factor that can maximize the power conversion efficiency of the variable field motor M at that time based on the torque command Tref and the motor speed ω, Using the field correction command value Idc input from the constant output control unit 13, the magnetic field is corrected in accordance with the change in the input voltage of the motor M. Note that a method for calculating the magnetic field in the magnetic field calculator 14 will be described in detail later.

As described above, in the motor control device 1 of the present embodiment, the control configuration is compared by performing dq-axis vector control in which the current command corresponding to the torque command Tref is divided into the d-axis current command Idref and the q-axis current command Iqref. The AC motor M can be functionally controlled in the same manner as a simple DC motor. Further, in the motor control device 1 of the present embodiment, by performing constant output control based on the reference voltage command value Vref, it is possible to stabilize the driving of the motor M in the high speed range. Further, in the motor control device 1 of the present embodiment, by adjusting the field of the variable field motor M by calculating the field ratio according to the torque command Tref, the motor speed ω, and the field factor correction command value Idc, The power conversion efficiency of the variable field motor M can be optimized.

<Outline of variable field motor>
An outline of an example of a variable field motor to be controlled by the motor control device 1 of the present embodiment will be described. 2 and 3 show only the rotor in the variable field motor M of this example in perspective. In FIGS. 2 and 3, the description of the rotating shaft is omitted to avoid the complexity of illustration. FIG. 4 shows an axial orthogonal cross section of the entire variable field motor M of this example.

The rotor 120 includes a magnetic pole portion 121 that generates a magnetic field and an iron core 122, and is configured as a field.

The magnetic pole part 121 is divided into three in the axial direction, and the magnetic pole part 121a at the center in the axial direction is rotatable relative to the load side magnetic pole part 121b and the anti-load side magnetic pole part 121c. Each of the

magnetic pole portions

121a, 121b, and 121c is configured by mounting a magnet 123 that generates a magnetic field in a substantially V-shaped mounting hole provided in the iron core 122 with the magnetization direction facing or back. The configuration including the three

magnetic pole portions

121a, 121b, and 121 that can be relatively rotated as described above corresponds to the variable field mechanism.

In this way, the field adjustment mechanism 9 is mechanically connected to the variable field mechanism provided in the variable field motor M (not shown), and the servo motor provided in the field adjustment mechanism 9 is driven. By rotating the central magnetic pole part 121a in the circumferential direction relative to the load-side field pole part 121b and the anti-load-side magnetic pole part 121c integrally fastened by The interlinkage magnetic flux that links between the two is changed.

That is, when the interlinkage magnetic flux is weakened, the relative angle of the central magnetic pole part 121a with respect to the load-side magnetic pole part 121b and the anti-load-side magnetic pole part 121c is increased by driving the field adjusting mechanism 9. In the state shown in FIG. 2, the central magnetic pole part 121a rotates relatively large with respect to the load-side magnetic pole part 121b and the anti-load-side magnetic pole part 121c, so that the magnetic poles cancel each other and the interlinkage magnetic flux is weakened.

On the other hand, when the flux linkage is strengthened, the relative angle of the central magnetic pole part 121a with respect to the load-side magnetic pole part 121b and the anti-load-side magnetic pole part 121c is decreased by driving the field adjusting mechanism 9. In the state shown in FIG. 3, the magnetic pole portion 121a at the center is aligned with the load-side magnetic pole portion 121b and the anti-load-side magnetic pole portion 121c, and the interlinkage magnetic flux is the strongest.

And the above-mentioned magnetic field ratio is the ratio of the interlinkage magnetic flux at that time with respect to the maximum interlinkage magnetic flux (rotor 120 side d-axis magnetic flux in FIG. 4) generated from the entire rotor 120 (as a range of values) In other words, in this example, it corresponds to the generation rate of the interlinkage magnetic flux when the central magnetic pole portion 121a is rotated relative to the load-side magnetic pole portion 121b and the anti-load-side magnetic pole portion 121c. To do. In the example of the present embodiment, the variable field mechanism included in the variable field motor M is configured to control the field magnetic flux by mechanical drive as described above. The structure etc. which control a field magnetic flux by are applicable.

The flow path of the interlinkage magnetic flux of the rotor 120 controlled as described above is shown in the cross-sectional view perpendicular to the axis in FIG. The variable field motor M in the example shown in the figure is a so-called 10P12S (P: pole = number of magnetic pole portions, S: provided with 12 teeth 112 in the

entire stator

110 and 10 iron cores 122 in the entire rotor 120). Slot = number of teeth). *

On the rotor 120 side, two permanent magnets 123 are arranged between adjacent iron cores 122, and the pair of permanent magnets 123 are magnetized in the same direction, and adjacent pairs are in a direction facing each other. Magnetized. As a result, the iron core 122 at a position where the N poles face each other between adjacent pairs becomes an N-type magnetic pole portion 122N that directs the N pole magnetic poles radially outward. Further, the iron core 122 at a position where the S poles face each other is an S-type magnetic pole portion 122S that directs the S pole magnetic poles outward in the radial direction. There are five N-type magnetic pole portions 122N and five S-type magnetic pole portions 122S, and they are alternately arranged along the circumferential direction.

In the above magnetic pole arrangement, the d-axis magnetic flux on the rotor 120 side circulates across the respective circumferential center positions in the direction from the adjacent S-type magnetic pole part 122S to the N-type magnetic pole part 122N. The axis extending in the direction shifted by 90 ° in electrical angle from the d-axis magnetic flux direction on the rotor 120 side is the q axis on the rotor 120 side. Then, by controlling the above-described field ratio, the rate of generation of magnetic flux on the rotor 120 side d-axis can be controlled.

On the other hand, on the stator 110 side, which is an armature, two adjacent teeth 112 are wound around the coil wires in opposite directions. Two adjacent teeth 112 form a set and correspond to the same current phase U, V, W. That is, in the mechanical stationary coordinates with the rotation axis of the output shaft 130 as the origin, the two pairs of adjacent teeth 112 whose mechanical arrangements are shifted by 30 ° from each other have an alternating magnetic field with a phase difference that is electrically shifted by 120 °. Will occur. As a result, a magnetic field rotating around the axis is generated in the stator 110, and the magnetic flux on the rotor 120 side rotates by receiving attraction and repulsion from the rotating magnetic field on the stator 110 side. At this time, the current component that circulates the magnetic flux around the teeth 112 arranged in the radial direction opposite to the d-axis on the rotor 120 side is the d-axis current Id, and as the rotor 120 rotates, the current component on the stator 110 side The d axis also rotates.

As described above, in the present embodiment, the motor control device 1 can variably control the d-axis interlinkage magnetic flux on the rotor 120 side of the variable field motor M by adjusting the magnetic field ratio, while the motor control. By adjusting the d-axis current command Idref with the device 1, the d-axis magnetic flux on the stator 110 side can be electrically variably controlled.

In such a configuration, it is possible to easily output a large torque to the variable field motor M by increasing both the d-axis magnetic flux on the rotor 120 side and the d-axis magnetic flux on the stator 110 side. However, when the d-axis magnetic flux on both the rotor 120 side and the stator 110 side is increased in this way, the induced voltage constant of the entire variable field motor M also increases. For this reason, a large induced voltage (counterelectromotive voltage) is generated in the high-speed rotation region, and as a result, it cannot be rotated at a higher speed due to insufficient output voltage. In addition, when the d-axis magnetic fluxes on both the rotor 120 side and the stator 110 side are reduced, the current (mainly q-axis current) required to output a large torque increases and the power efficiency decreases. . In other words, the variable field motor M easily generates torque when the field ratio and d-axis current are large, and easily outputs the motor speed ω while suppressing the output voltage when each is small (because the induced voltage is small). . As described above, by performing field control of the rotor 120 side d-axis and the stator 110 side d-axis in a coordinated manner, the power efficiency of the variable field motor M and the operation speed range can be increased.

<Features of this embodiment>
As described above, the motor control device 1 of the present embodiment changes the field magnetic flux of the variable magnetic field motor M using the field ratio as a control parameter, and the optimum value of this field ratio is changed by the constant output control. It is also greatly affected by the power supply voltage of the battery and the torque command. Even when the motor characteristics change due to a temperature change or the like, the optimum value of the magnetic field factor fluctuates, making it difficult to maintain the optimum control state.

On the other hand, in this embodiment, the constant output control unit 13 generates a field factor correction command value Idc based on the voltage command value V1 and the reference voltage command value Vref, and the field factor calculation unit 14 uses the field factor correction command. Based on the value Idc, by calculating a field rate suitable for driving the variable field motor M at that time, constant field control and variable field flux control suitable for temperature change are performed. . Hereinafter, the configuration and function of the constant output control unit 13 and the magnetic field factor calculation unit 14 will be described in order.

<Internal configuration of constant output controller>
FIG. 5 schematically shows the internal configuration of the constant output control unit 13. In FIG. 5, the constant output control unit 13 includes a subtractor 131, a PI control unit 132, a filter 133, a constant output control Id limiter 134, and a field factor adjustment Id limiter 135.

The subtractor 131 takes a difference obtained by subtracting the voltage command value V1 input from the voltage command value calculation unit 12 from the reference voltage command value Vref input from the outside, and calculates a difference between the reference voltage command values Vref (see A in the figure). Output as. The reference voltage command value Vref is preferably set to be equal to the power supply voltage at that time (particularly, the DC bus voltage or battery voltage of a converter not shown), but is set to an arbitrary value other than that. Also good.

The PI control unit 132 includes, for example, an appropriate gain, an integrator, and the like, and performs so-called PI control so that the command value deviation is reduced in the voltage control system feedback loop (not particularly shown).

The filter 133 functions to remove a high frequency band component included in the command value deviation output from the PI control unit 132 and suppress vibration caused by the sampling frequency of the command value deviation.

The constant output control Id limiter 134 outputs, as the d-axis current command correction value ΔIdref, a value obtained by setting the positive value to substantially zero and the negative value to a predetermined minimum value with respect to the command value deviation input from the filter 133. To do.

The field-adjustment Id limiter 135 limits the maximum absolute value of the command value deviation input from the filter 133 to a predetermined value, and outputs a field factor correction command value Idc. In this example, the predetermined minimum value in the constant output control Id limiter 134 and the predetermined maximum absolute value in the field-adjustment Id limiter 235 are set to be substantially equal to each other.

The constant output control unit 13 configured as described above outputs the d-axis current command correction value ΔIdref and adjusts the d-axis current command Idref, thereby generating the d-axis magnetic flux on the stator 110 side of the variable field motor M. Weak so-called field weakening control is performed. In other words, this field weakening control is performed with respect to the d-axis current command Idref generated optimally in terms of power efficiency by the high-efficiency control unit 2 in order to expand the high-speed rotation range of the variable field motor M as described above. Only control is performed to decrease, and control to increase is not performed.

Note that the constant absolute output control Id limiter 134 and the field ratio adjustment Id limiter 135 each limit the maximum absolute output value to a predetermined value (set a negative lower limit and a positive upper limit). This is for suppressing excessive correction of the d-axis current command Iderf and the magnetic field even when the input voltage is greatly increased or decreased.

<Field factor calculation processing performed by the field factor calculator>
FIG. 18 shows a flow of a field factor calculation process executed in the field factor calculator 14 by a CPU (not shown) included in the motor control device 1 of the present embodiment.

First, in step S <b> 5, the CPU of the motor control device 1 inputs a field factor correction command value Idc from the constant output control unit 13.

Next, the process proceeds to step S10, and the CPU of the motor control device 1 sets the converted field ratio by table conversion (detailed later) based on the torque command and the motor speed.

Next, the process proceeds to step S15, and the CPU of the motor control device 1 determines whether or not the field factor correction command value Idc input in step S5 is a negative value (<0). If the field factor correction command value Idc is a negative value, the determination is satisfied, and the routine goes to Step S20.

In step S20, the CPU of the motor control device 1 adds a value obtained by multiplying the field factor correction command value Idc input in step S5 by the coefficient K to the converted field factor set in step S10. In other words, the final magnetic field is calculated by correcting the magnetic field to decrease. The coefficient K is a coefficient for changing the field factor correction command value Idc to a unit of field factor. Then, this flow ends.

On the other hand, if the field correction command value Idc is a positive value (> 0) in the determination in step S15, the determination is not satisfied and the process proceeds to step S25.

In step S25, the CPU of the motor control device 1 adds a value obtained by multiplying the field factor correction command value Idc input in step S5 by the coefficient K to the converted field factor set in step S10. In other words, the final field ratio is calculated by correcting the field ratio to increase. Then, this flow ends.

As described above, the field factor calculation unit 14 included in the present embodiment has the field factor correction command value output by the constant output control unit 13 with respect to the converted field factor calculated by table conversion based on the torque command Tref and the motor speed ω. The final field susceptibility is calculated by correcting with Idc. At this time, if the field correction command value Idc is a positive value, the field factor is corrected to increase, and if the field factor correction command value Idc is a negative value, the field factor is corrected to decrease.

FIG. 7 shows an example of a field ratio table used for table conversion in step S10. In a general variable field motor M, the power conversion efficiency can be actively changed by changing the field factor to expand the output range. However, before that, the power conversion efficiency itself is the motor as described above. It changes passively according to the output. The relationship between these is often a complex relationship that does not fit into a simple calculation formula. For this reason, in the motor control device 1 of the present embodiment, the field factor calculation unit 14 includes a field factor table as shown in FIG. 7 and sets an appropriate converted field factor by table conversion with reference to this table. In this field factor table, parameters related to the motor output are used as key variables, and a correlation with a field factor capable of minimizing the input power corresponding to these parameters is stored. As an example shown in FIG. 7, the orthogonal coordinates are taken with two parameters of the torque of the motor M (substitute with the torque command Tref) and the motor rotation speed (= motor speed ω), and the input power is minimized corresponding to the combination thereof. A field table is composed of a binary table that stores field values that can be converted into values.

<Coordinated control of d-axis field by constant output controller and field factor calculator>
The coordinated control of the d-axis field by the constant output controller 13 and the field factor calculator 14 configured as described above will be described in detail below. First, as described above, the constant output control unit 13 provided in the present embodiment decreases with respect to the d-axis current command Idref generated by the high efficiency control unit 2 when the high-speed rotation range of the variable field motor M is expanded. The field weakening control is performed to control. In this field weakening control, only control to decrease the d-axis current command Idref is performed, and control to increase is not performed. That is, the d-axis current command correction value ΔIdref is not output as a positive value.

For example, from the voltage-current equation:
Vq = R · Iq + Lq · (d / dt) Iq + ωLd · Id + φω
The relationship holds. R, Ld, and Lq are the winding resistance of the motor M, the winding inductance of the d-axis and the q-axis, respectively, and φ is the magnetic flux density. In the above equation, the term of φω corresponds to the induced voltage, and the induced voltage φω can be canceled by setting Id to a negative value (<0) by field weakening control. As described above, when the constant output control unit 13 performs field weakening control, the constant output control Id limiter 134 limits the d-axis current command correction value ΔIdref to a negative value of 0 or less. Then, the Iq command generation unit 3 generates the q-axis current command Iqref based on the d-axis current command Idref that has been adjusted to decrease in this way.

On the other hand, in the constant output control unit 13 having the above-described configuration, the field factor correction command value Idc, which can take both a positive value (> 0) and a negative value, is obtained via the field factor adjustment Id limiter 135 as described above. Output for correction. In this embodiment, the constant power control unit 13 outputs the field factor correction command value Idc for correcting the field factor as both a positive value and a negative value. You can do both. That is, in this embodiment, when the constant output control unit 13 performs field weakening control to expand the high-speed rotation range, the d-axis magnetic flux is weakened on both the stator 110 side and the rotor 120 side, and the constant output control unit When 13 cancels the field weakening control and increases the torque, control is performed so as to increase the d-axis magnetic flux only on the rotor 120 side.

Here, it is noted that both the d-axis current command correction value ΔIdref and the field factor correction command value Idc are generated based on the command value deviation in the voltage control system feedback loop. As described above, this command value deviation is a deviation between the voltage command value V1 actually input to the motor M and the reference voltage command value Vref, and the voltage control system feedback loop always reduces this command value deviation. Control to do. Thus, when the maximum voltage (for example, a power supply voltage of a battery or the like) that can be supplied to the motor M at that time is set to the reference voltage command value Vref, the voltage command value V1 actually input to the motor M is always referred to. By approximating the voltage command value Vref, the saturation state of the motor output voltage can be maintained. In this motor output power saturation state, the motor output calculated by the motor speed ω × torque can maintain a constant output state where the motor output is constant, and a desirable state in which the motor speed ω and torque are in a substantially inversely proportional relationship is maintained. it can. This is the original function of the voltage control system feedback loop including the constant output control unit 13.

However, as described above, the constant output control unit 13 provided in the present embodiment outputs only the negative value of the command value deviation as the d-axis current command correction value ΔIdref, so that the d-axis is used for field weakening control. Even though the current command Idref is controlled to be decreased, the control to increase is not performed. On the other hand, the constant output control unit 13 provided in the present embodiment outputs the field factor correction command value Idc by both the positive value and the negative value of the command value deviation to correct the field factor, thereby making the constant output described above. The state can be maintained.

For example, when the voltage command value V1 increases beyond the reference voltage command value Vref as the torque command Tref increases, the command value deviation of the voltage control system feedback loop becomes a negative value. As a result, both the d-axis current command correction value ΔIdref and the field factor correction command value Idc become negative values, the field weakening control and the field factor decrease correction are performed simultaneously, and the induced voltage of the motor M is reduced. The high-speed rotation range can be expanded (the motor speed ω can be easily increased while suppressing the output voltage) At this time, when the induced voltage decreases, the voltage command value V1 also decreases accordingly, so that the voltage command value V1 approaches the reference voltage command value Vref and the command value deviation approaches zero. By such a restoration function of the voltage control system feedback loop, the d-axis current command correction value ΔIdref and the field factor correction command value Idc can be finally converged to 0, the field weakening control is canceled, and the field factor (Decrease correction is canceled and the converted magnetic field factor is restored). That is, through such a process, even when the torque command Tref increases, the stator 110 side and the rotor are connected to each other while maintaining the constant output state by approximating the voltage command value V1 to the reference voltage command value Vref. The induced voltage of the motor M can be reduced by adjusting the balance of the respective d-axis magnetic fluxes on the 120 side, the high speed rotation range can be expanded, and the motor speed ω can be easily obtained.

Conversely, when the voltage command value V1 decreases below the reference voltage command value Vref as the torque command Tref decreases, the command value deviation of the voltage control system feedback loop becomes a positive value. In this case, the d-axis current command correction value ΔIdref is limited to 0 and only the field factor correction command value Idc becomes a positive value, and only the increase in the field factor is performed. The torque output with efficiency can be maintained. At this time, when the induced voltage increases due to the increase of the magnetic field, the voltage command value V1 also increases accordingly. Therefore, the voltage command value V1 approaches the reference voltage command value Vref and the command value deviation approaches zero. By such a restoration function of the voltage control system feedback loop, the d-axis current command correction value ΔIdref and the field factor correction command value Idc can be finally converged to 0, and the field factor decreases (the increase correction is canceled). To return to the converted magnetic field). That is, through such a process, even when the torque command Tref is reduced, the stator 110 side and the rotor are maintained while maintaining the constant output state by approximating the voltage command value V1 to the reference voltage command value Vref. The induced voltage of the motor M can be increased by adjusting the balance of the respective d-axis magnetic fluxes on the 120 side, and the torque output with appropriate power efficiency can be maintained.

<Effect obtained by this embodiment>
According to this embodiment described above, the following effects are obtained. That is, in the motor control device 1 of the present embodiment, the constant output control unit 13 generates the field correction command value Idc based on the voltage command value V1 and the reference voltage command value Vref, and the field factor calculation unit 14 Based on the correction command value Idc, a field ratio appropriate for driving the variable field motor M at that time is calculated. That is, the field control on the rotor 120 side is controlled based on the voltage command value V and the reference voltage command value Vref, which are field control parameters on the stator 110 side, so that the field control on each of the stator 110 side and the rotor 120 side is performed. Can be performed in cooperation. As a result, the field magnetic flux of the variable field motor M can be appropriately variably controlled while maintaining constant output control, and the output range can be functionally expanded without disabling the variable field motor M.

Particularly in this embodiment, the field correction command value Idc is not generated by table conversion, but is generated by a control system using a voltage control system feedback loop. For this reason, the above function can be realized with a simple configuration without using a temperature detection sensor or a complicated table corresponding to the temperature change even for a characteristic change due to a temperature change of the motor M, and the variable field motor M is also included. There is an advantage that it is not easily affected by aging of machines and individual differences.

In the present embodiment, in particular, the constant output controller 13 generates the field correction command value Idc based on the command value deviation between the voltage command value V1 and the reference voltage command value Vref. The command value deviation between the voltage command value V1 and the reference voltage command value Vref corresponds to the voltage deviation in the voltage control system feedback loop described above. For this reason, the constant output control unit 13 generates a field factor correction command value Idc based on the command value deviation, so that the field factor calculation unit 14 corrects the field factor in accordance with the change in the input voltage of the motor M. Can be done appropriately.

In the present embodiment, in particular, the constant output control unit 13 generates a value in which the maximum absolute value of the command value deviation is limited by the field-adjustment Id limiter 135 as the field-correction command value Idc. Thereby, even when the input voltage of the motor M is greatly increased or decreased, the constant output control unit 13 can suppress excessive correction of the magnetic field factor and can maintain a suitable magnetic field factor for driving the motor M.

In this embodiment, in particular, the field factor calculator 14 corrects the value calculated by table conversion based on the torque command Tref and the motor speed ω with the field factor correction command value Idc to calculate the field factor. As a result, the field ratio calculation unit 14 drives based on the torque command Tref serving as an input reference to the variable magnetic field motor M and the motor speed ω corresponding to the detection output of the variable field motor M. Therefore, it is possible to functionally obtain an appropriate field ratio, and to appropriately correct the field ratio in accordance with the increase / decrease change of the input voltage of the motor M. As a result, it is possible to realize optimal field ratio control while maintaining a constant output state. Further, since the relationship between the torque command Tref, the motor speed ω, and the field rate is a characteristic unique to the variable field motor M to be controlled, a field rate table showing the correlation between them is created in advance and converted. Thus, the magnetic field can be calculated quickly and functionally.

In the present embodiment, in particular, the constant output control unit 13 generates the d-axis current command correction value ΔIdref for correcting the d-axis current command Idref based on the command value deviation. The command value deviation between the voltage command value V1 and the reference voltage command value Vref corresponds to the voltage deviation in the voltage control system feedback loop. For this reason, the constant output control unit 13 generates the d-axis current command correction value ΔIdref based on the command value deviation, so that the field factor calculation unit 14 causes the field weakening current to flow according to the increase / decrease change of the input voltage of the motor. Thus, it is possible to appropriately correct the d-axis current command Idref.

In the present embodiment, in particular, the constant output control unit 13 uses the constant output control Id limiter 134 to set a value obtained by setting the positive value of the command value deviation to approximately 0 and limiting the minimum negative value to the d-axis current command correction value ΔIdref. Generate as As a result, the voltage control system feedback loop can only perform a correction for decreasing the d-axis current command Idref, that is, a field weakening that weakens the induced voltage without correcting the d-axis current so as to increase the induced voltage. Since the d-axis current is corrected so that only the current flows, the high-speed rotation range can be expanded. Further, even when the input voltage of the motor M greatly increases, the constant output control unit 13 can suppress excessive decrease correction with respect to the d-axis current command Idref, and can maintain a d-axis current appropriate for driving the motor M.

<Modification>
The disclosed embodiments are not limited to the above, and various modifications can be made without departing from the spirit and technical idea thereof. Hereinafter, such modifications will be described.

(1) When the field correction command value is generated by the difference between the input and output of the constant output control Id limiter In the above embodiment, the field adjustment Id limiter 135 sets a value obtained by limiting the maximum absolute value of the command value deviation. Although generated as the field correction command value Idc, the present invention is not limited to this. For example, as shown in FIG. 8 corresponding to FIG. 5, the input and output of the constant output control Id limiter 134 in the constant output control unit 13A, that is, the difference value between the command value deviation and the d-axis current command correction value ΔIdref is calculated. It may be generated as a field factor correction command value Idc. In this case, the field correction command value Idc is output only when the command value deviation is smaller than the positive value or the limited negative value (0 is output for a negative value greater than the limit value). As a result, when the constant output control unit 13 performs field weakening control and expands the high-speed rotation range, it is weakened on both the stator 110 side and the rotor 210 side in the above embodiment. Then, control is performed so as to weaken the d-axis magnetic flux only on the stator 110 side. Further, when the constant output control unit 13 cancels the field weakening control and increases the torque, this modified example also controls to increase the d-axis magnetic flux only on the rotor 120 side as in the above embodiment. Note that the field control correction command value Idc smaller than the limited negative value is not output by the voltage control system feedback loop restoration function as described above.

(2) When the field factor is calculated by correcting the maximum field factor with the field factor correction command value In the above embodiment, with respect to the converted field factor obtained by table conversion based on the torque command value Tref and the motor speed ω. Thus, the value corrected by the field factor correction command value Idc is calculated as the field factor, but the present invention is not limited to this. For example, as shown in FIG. 9 corresponding to FIG. 6 described above, instead of step S10 for setting the converted field rate by table conversion, the step of initially setting the field factor to the maximum field rate (for example, 99.9%) S10A is executed. Then, instead of steps S20 and S25 for correcting the converted field rate with the field factor correction command value Idc, steps S20A and S25A for correcting the maximum field factor set in step S10A with the field factor correction command value Idc. Execute.

This makes it possible to appropriately correct the magnetic field in accordance with the increase / decrease in the input voltage of the motor M with a simple configuration without preparing a complicated magnetic field table as shown in FIG. In this case, although it takes time to correct the initially set maximum field factor to an appropriate field factor, as a result, the stator 110 side and the rotor 120 side correspond to the torque command Tref. The balance of each of the d-axis fields is balanced and converges to an appropriate value. As a result, it is possible to expand the operation region at the optimum field ratio while maintaining the constant output state as in the above embodiment.

In addition to those already described above, the methods according to the above-described embodiment and each modification may be used in appropriate combination.

In addition, although not illustrated one by one, the above-described embodiment and each modification are implemented with various modifications within a range not departing from the gist thereof.

DESCRIPTION OF SYMBOLS 1 Motor controller 2 High efficiency control part 3 Iq command generation part 4 ACR
5 dq / 3 phase converter 6 PWM converter 7 inverter 8 current detector 9 field adjustment mechanism 10 3 phase / dq converter 11 differentiator 12 voltage command value calculator (voltage calculator)
13, 13A Constant output control unit 14 Field factor calculation unit 132 PI control unit 133 Filter 134 Id limiter for constant output control 135 Id limiter for field factor adjustment

Claims

A motor control device that controls driving of a variable field motor having a variable field mechanism that varies a field magnetic flux,
A voltage calculator configured to calculate a voltage command value;
A constant output control unit configured to generate a field correction command value based on the voltage command value and an arbitrarily set reference voltage command value;
A field factor calculator configured to calculate a field factor of the variable field motor based on the field factor correction command value;
A motor control device comprising:
The constant output controller is
The motor control device according to claim 1, wherein the field correction command value is generated based on a command value deviation between the voltage command value and the reference voltage command value.
The constant output controller is
3. The motor control device according to claim 2, wherein a value obtained by limiting a maximum absolute value of the command value deviation by a field factor adjustment Id limiter is generated as the field factor correction command value.
The magnetic field factor calculator is
4. The motor control device according to claim 3, wherein the field factor is calculated by correcting the value calculated by table conversion based on a torque command and a motor speed with the field correction command value.
The magnetic field factor calculator is
The motor control device according to claim 3, wherein the field factor is calculated by correcting the maximum field factor with the field factor correction command value.
The constant output controller is
6. The motor control device according to claim 5, wherein a d-axis current command correction value for correcting a d-axis current command is generated based on the command value deviation.
The constant output controller is
7. The motor control according to claim 6, wherein a constant value control Id limiter generates a value obtained by limiting the positive value of the command value deviation to approximately 0 and limiting the minimum negative value as the d-axis current command correction value. apparatus.
The constant output controller is
The motor control device according to claim 7, wherein a difference value between the command value deviation and the d-axis current command correction value is generated as the field correction command value.
A motor control method for controlling the driving of a variable field motor having a variable field mechanism that varies a field magnetic flux,
Calculating a voltage command value;
Generating a field correction command value based on the voltage command value and an arbitrarily set reference voltage command value;
Calculating a field factor of the variable field motor based on the field factor correction command value;
The motor control method characterized by performing.