阅读说明：本技术 电动机的控制方法以及电动机的控制装置 (Motor control method and motor control device ) 是由 大野翔 川村弘道 于 2017-12-01 设计创作，主要内容包括：控制装置(100)基于扭矩指令值而对表示减小向电动机(9)供给的电流的偏差的电压值的反馈指令值、和补偿该指令值的前馈补偿值进行运算,由此输出电流矢量控制的电压指令值。在将对电动机(9)的控制从电流矢量控制向电压相位控制切换的情况下,控制装置(100)基于电流矢量控制的运算值对电压相位控制进行初始化,基于扭矩指令值而执行针对规定的电压相位指令值的反馈控制,由此输出电压相位控制的电压指令值。在对电压相位控制进行初始化的情况下,控制装置(100)对反馈指令值实施使该指令值的低频分量通过的滤波处理,利用前馈补偿值以及滤波处理后的反馈指令值而对电压相位指令值的初始值进行运算。(The control device (100) outputs a current vector control voltage command value by calculating a feedback command value indicating a voltage value that reduces a deviation of a current supplied to the motor (9) and a feedforward compensation value that compensates the command value, based on the torque command value. When the control of the motor (9) is switched from current vector control to voltage phase control, the control device (100) initializes the voltage phase control on the basis of the calculated value of the current vector control, and executes feedback control for a predetermined voltage phase command value on the basis of the torque command value, thereby outputting the voltage command value of the voltage phase control. When voltage phase control is initialized, the control device (100) performs filtering processing for passing low-frequency components of the feedback command value, and calculates an initial value of the voltage phase command value using the feedforward compensation value and the feedback command value after the filtering processing.)

1. A control method of a motor that performs any one of current vector control and voltage phase control for controlling electric power supplied to the motor, in accordance with an operating state of the motor,

the control method of the motor includes:

a current control step of outputting a voltage command value for the current vector control by calculating a feedback command value indicating a voltage value that reduces a deviation of a current supplied to the motor and a feedforward compensation value that compensates the feedback command value, based on a torque command value for the motor;

a switching control step of initializing the voltage phase control based on a calculated value of the current vector control when switching control of the motor from the current vector control to the voltage phase control; and

a voltage phase control step of performing feedback control for a predetermined voltage phase command value based on a torque command value of the electric motor to output a voltage command value for the voltage phase control,

in the switching control step, the feedback command value is subjected to filtering processing for passing a low-frequency component of the command value, and an initial value of the voltage phase command value is calculated using the feedforward compensation value and the feedback command value after the filtering processing.

2. The control method of an electric motor according to claim 1,

in the switching control step, the integrated value of the feedback control is updated based on the initial value.

3. The control method of an electric motor according to claim 2,

the feedback control is a control in which the voltage phase command value is fed back to the torque generated in the motor,

in the switching control step, a value obtained by subtracting a feedforward component of the voltage phase command value from the initial value is set as the integrated value.

4. A control device for an electric motor, which executes either of current vector control and voltage phase control for controlling electric power supplied to the electric motor, in accordance with an operating state of the electric motor,

the control device for the motor comprises:

an inverter that supplies ac power to the motor based on control of the motor;

a sensor that detects a current supplied from the inverter to the motor;

a controller that executes the current vector control by calculating a feedback command value indicating a voltage value that reduces a deviation of a current supplied to the motor and a feedforward compensation value that compensates the command value, based on a torque command value of the motor; and

a filter for applying a filtering process for passing a low-frequency component of the feedback command value to the command value,

when the control of the motor is switched to the voltage phase control, the controller initializes the voltage phase control based on the feedforward compensation value and the output of the filter.

Technical Field

The present invention relates to a motor control method and a motor control device for switching control of a motor to another control according to a state of the motor.

Background

As a control method of the motor, for example, a current vector control in which a value of a current supplied to the motor is fed back to a voltage command value, a voltage phase control in which a value of a torque generated by the motor is fed back to a voltage phase command value, and the like are known. These controls are often performed in accordance with the operating state of the electric motor.

As one of the control devices described above, there is proposed a control device that initializes a control state variable of voltage phase control based on a voltage command value of current vector control when switching control of a motor from current vector control to voltage phase control (JP2007-143235 a).

Disclosure of Invention

However, in the above-described control device, the ripple may be superimposed on the voltage command value for the current vector control according to error characteristics of a current sensor or the like that detects the current supplied to the motor. In this case, if the control of the motor is switched from the current vector control to the voltage phase control, the torque of the motor may fluctuate due to the pulsation component of the voltage command value.

An object of the present invention is to provide a control method and a control device for a motor for suppressing a variation in torque of the motor that occurs when control of the motor is switched to voltage phase control.

According to one aspect of the present invention, a method for controlling a motor executes either current vector control or voltage phase control for controlling electric power supplied to the motor, in accordance with an operating state of the motor. The motor control method includes a current control step of outputting a voltage command value for the current vector control by calculating a feedback command value indicating a voltage value that reduces a deviation of a current supplied to the motor and a feedforward compensation value that compensates the feedback command value, based on a torque command value of the motor. The motor control method includes: a switching control step of initializing the voltage phase control based on a calculated value of the current vector control when switching control of the motor from the current vector control to the voltage phase control; and a voltage phase control step of outputting a voltage command value for the voltage phase control by performing feedback control for a predetermined voltage phase command value based on a torque command value for the electric motor. In the switching control step, a filter process for passing a low-frequency component of the command value is performed on the feedback command value, and an initial value of the voltage phase command value is calculated using the feedforward compensation value and the feedback command value after the filter process.

Drawings

Fig. 1 is a diagram showing a configuration example of a motor control device according to an embodiment of the present invention.

Fig. 2 is a block diagram showing a configuration example of a current vector control unit of the control device of the present embodiment.

Fig. 3 is a block diagram showing a configuration example of an initial value calculation unit of the control device according to the present embodiment.

Fig. 4 is a block diagram showing a configuration example of a voltage phase control unit of the control device of the present embodiment.

Fig. 5 is a diagram illustrating a variation in torque of the motor that occurs when switching to the voltage phase control.

Fig. 6 is a flowchart showing a motor control method according to the present embodiment.

Detailed Description

Embodiments of the present invention will be described below with reference to the drawings.

(embodiment 1)

Fig. 1 is a diagram showing a configuration example of a motor control device 100 according to embodiment 1 of the present invention.

The control device 100 controls the electric power supplied to the motor 9 by executing a pre-programmed process. The control device 100 is constituted by, for example, 1 or more controllers.

The control device 100 includes a current vector control unit 1, a voltage phase control unit 2, a control switching unit 3, a coordinate converter 4, a PWM converter 5, an inverter 6, a battery voltage detector 7, a motor current detector 8, and a motor 9. The control device 100 further includes a rotor detector 10, a rotational speed calculator 11, a coordinate converter 12, and an initial value calculation unit 13.

The current vector control unit 1 executes current vector control so that the torque generated by the electric motor 9 converges to a predetermined torque command value T. The current vector control described here is a control method for controlling the operation of the motor 9 by changing the direction and magnitude of a vector relating to the current supplied to the motor 9.

The current vector control unit 1 performs feedback of the current value of the electric power supplied from the battery 61 to the motor 9 via the inverter 6 to the voltage command value v based on the torque command value T of the motor 9_diAnd v_qiFeedback control of x.

The current vector control unit 1 of the present embodiment uses the torque command value T, the rotation speed detection value N, and the battery voltage detection value V of the motor 9_dcDetecting d-axis current value i_dFeeds back to the d-axis voltage command value V_diDetecting q-axis current value i_qFeeds back the q-axis voltage command value V_qi*. The d-axis current detection value i referred to here_dAnd q-axis current detection value i_qRespectively representing the value of the d-axis component and the value of the q-axis component of the current supplied to the motor 9. The d-axis and the q-axis are mutually orthogonal coordinate axes.

The current vector control unit 1 calculates a d-axis voltage command value v by feedback control_diVoltage command value v of x and q axes_qiAnd outputs the voltage command value to the control switching unit 3 as a current vector control voltage command value.

The voltage phase control unit 2 executes voltage phase control so that the torque generated by the electric motor 9 converges to the torque command value T. The voltage phase control described here is a control method for controlling the operation of the motor 9 by changing the voltage phase, which is the phase between the supply voltages of the respective phases of the motor 9.

The voltage phase control unit 2 performs feedback of the current value of the electric power supplied from the battery 61 to the motor 9 via the inverter 6 to the voltage command value v based on the torque command value T_dvA and v_qvFeedback control of x.

The voltage phase control unit 2 of the present embodiment uses the torque command value T, the rotation speed detection value N, and the battery voltage detection value V_dcThe specified voltage amplitude command value and voltage phase command value are calculated, and d-axis and q-axis current detection values i are used_dAnd i_qAnd feeds back the voltage phase command value. The voltage phase control unit 2 calculates a d-axis voltage command value v by feedback control_dvVoltage command value v of x and q axes_qvAnd outputs the voltage command value to the control switching unit 3 as a voltage phase control voltage command value.

The control switching unit 3 switches the control of the motor 9 to either of the current vector control and the voltage phase control in accordance with the control mode flag CNT _ F L G.

In the present embodiment, the identifier indicating the current vector control is "1", the identifier indicating the voltage phase control is "2", and the identifier indicating the other control executed in an emergency is "3".

Using a torque command value T and a d-axis current detection value i representing the operating state of the motor 9_dFor example, when the torque of the motor 9 is low, an identifier indicating current vector control is set for the control mode flag CNT _ F L G, and when the magnitude of the current vector reaches a predetermined threshold value, an identifier indicating voltage phase control is set.

The control switching unit 3 calculates at least a value calculated by control selected from the current vector control and the voltage phase control as final voltage command values v for the d-axis and the q-axis_dA and v_qOutput to the coordinate transformer 4.

The coordinate converter 4 converts the final voltage command values v of the d-axis and the q-axis based on the electric angle detection value θ of the motor 9 as in equation (1)_dA and v_qConversion into three-phase voltage command value v_u*、v_vA and v_w*。

[ formula 1]

PWM converter 5 detects value V based on battery voltage of battery 61_dcWhile the three-phase voltage command value V is converted into_u*、V_vA and V_wInto power element drive signals D for driving the power elements arranged in the inverter 6_uu*、D_ul*、D_vu*、D_vl*、D_wuA and D_wl*. PWM converter 5 converts power element drive signal D_uu*、D_ul*、D_vu*、D_vl*、D_wuA and D_wlTo the power elements of the inverter 6.

Inverter 6 drives signal D based on power element_uu*、D_ul*、D_vu*、D_vl*、D_wuA and D_wlConverts the dc voltage of the battery 61 into a three-phase ac voltage v for driving the motor 9_u、v_vAnd v_w. The inverter 6 converts the three-phase AC voltage v_u、v_vAnd v_wTo each phase of the motor 9.

The battery voltage detector 7 detects the voltage of the battery 61 connected to the inverter 6. The battery voltage detector 7 detects a battery voltage value V indicating the detected voltage value_dcThe outputs are respectively output to the current vector control unit 1 and the voltage phase control unit 2.

The motor current detector 8 detects three-phase ac currents i for the respective phases supplied from the inverter 6 to the motor 9_u、i_vAnd i_wAt least two phases of alternating currents are detected. The motor current detector 8 of the present embodiment detects the U-phase and V-phase alternating currents i_uAnd i_vPerforming detection to beMeasured AC current i_uAnd i_vOutput to the coordinate transformer 12.

The motor 9 is a motor that has windings (e.g., U, V and W three-phase windings) in each of multiple phases and is driven to rotate by supplying ac power to each phase winding. The motor 9 may be used as a drive source of an electric vehicle or the like. For example, the motor 9 is implemented by a three-phase synchronous motor of ipm (interior Permanent magnet) type.

The rotor detector 10 detects an electrical angle of the motor 9. The rotor detector 10 outputs electrical angle detection values θ indicating the detected electrical angle values to the coordinate converter 4 and the coordinate converter 12, respectively, and outputs the electrical angle detection values θ to the rotational speed calculator 11.

The rotation speed calculator 11 calculates the rotation speed of the motor 9 based on the amount of change per unit time of the electrical angle detection value θ. The rotation speed calculator 11 outputs a rotation speed detection value N indicating the calculated rotation speed to the current vector control unit 1 and the voltage phase control unit 2, respectively.

The coordinate converter 12 converts the U-phase and V-phase alternating currents i based on the electric angle detection value θ of the motor 9 as shown in equation (2)_uAnd i_vConverted into d-axis current detection value i_dAnd q-axis current detection value i_q. The coordinate converter 12 detects the d-axis current i_dAnd q-axis current detection value i_qThe outputs are respectively output to the current vector control unit 1 and the voltage phase control unit 2.

[ formula 2]

The initial value calculation unit 13 initializes the voltage phase control unit 2 based on the calculated value of the current vector control unit 1. For example, when the control of the motor 9 is switched from the current vector control to the voltage phase control, the initial value calculation unit 13 resets the state variable of the voltage phase control unit 2 based on the calculated value of the current vector control unit 1.

When the identifier indicated by the control mode flag CNT _ F L G is switched from "1" to "2", the initial value calculation unit 13 of the present embodiment sets the state variable of the voltage phase control unit 2 to the initial value based on the calculated value of the current vector control unit 1.

Fig. 2 is a block diagram showing a configuration example of the current vector control unit 1 according to the present embodiment. For d-axis voltage command value v_diStructure for performing operation and command value v for q-axis voltage_qiSince the structures for performing the arithmetic operations are the same, only the d-axis voltage command value v will be described here_diStructure of performing operations.

The current vector control unit 1 includes a non-interference voltage arithmetic unit 101, a current target value arithmetic unit 102, a subtraction unit 103, a PI controller 104, and an addition unit 105.

The non-interference voltage calculator 101 compensates the d-axis voltage command value v based on the torque command value T_diAnd calculating the feedforward compensation value.

The non-interference voltage calculator 101 of the present embodiment is based on the torque command value T, the rotation speed detection value N, and the battery voltage detection value V_dcA non-interference voltage value V to be used for eliminating an interference voltage interfering with each other between the d-axis and the q-axis_{d_dcpl}Operating as a feedforward compensation value. Then, the non-interference voltage calculator 101 calculates the non-interference voltage value v_{d_dcpl}Outputs to the adder 106.

For example, the non-interference voltage calculator 101 stores a predetermined non-interference table. In the non-interference meter, the torque command value T, the rotation speed detection value N and the battery voltage detection value V are used for_dcDetermined per action point and non-interfering voltage value V_{d_dcpl}Establish an association.

The non-interference voltage calculator 101 obtains a torque command value T, a rotation speed detection value N, and a battery voltage detection value V_dcThe respective parameters of (1). Then, the non-disturbance voltage calculator 101 refers to the non-disturbance table, determines the operating point of the motor 9 based on each parameter, and sets the non-disturbance voltage value v associated with the operating point_{d_dcpl}Make a calculation.

For reducing the current supplied to the motor 9The deviation, current target value calculator 102 calculates a d-axis current target value i for the motor 9 based on the torque command value T_dAnd performing operation.

The current target value calculator 102 of the present embodiment is based on the torque command value T, the rotation speed detection value N, and the battery voltage detection value V, as in the non-interference voltage calculator 101_dcA d-axis current target value i is set with reference to a predetermined ammeter_dAnd performing operation.

For example, the current meter is used for the torque command value T, the rotation speed detection value N and the battery voltage detection value V_dcDetermined each operating point and d-axis current target value i_dEstablish an association. D-axis current target value i of ammeter_dThe current value is stored as a current value for the motor 9 necessary for the motor 9 to perform an operation based on the torque command value T and as a current value for maximizing the efficiency of the motor 9.

The current value stored in the ammeter is appropriately set by experimental data, simulation, and the like. The current target value arithmetic unit 102 calculates a d-axis current target value i_dOutputs the signals to the initial value calculation unit 13 and the subtraction unit 103, respectively.

The subtractor 103 outputs a d-axis current target value i_dSubtracting d-axis current detection value i from_dThe value obtained by the subtraction is output to the PI controller 104 as a d-axis current deviation.

The PI controller 104 calculates a feedback command value indicating a voltage value for reducing a deviation of the supply current of the motor 9 based on the torque command value.

The PI controller 104 of the present embodiment performs current feedback control such that the d-axis current detection value i_dTracking d-axis current target value i_dFeeding back the d-axis current deviation to the d-axis voltage command value v_di*。

For example, the PI controller 104 is based on the d-axis current offset i as in equation (3)_{d_err}(＝i_d*-i_d) For current FB voltage command value v_{d_fb}The calculation is performed as a feedback command value.

[ formula 3]

Wherein, K_dpIs the d-axis proportional gain, K_diIs the d-axis integral gain. d-axis proportional gain K_dpAnd d-axis integral gain K_diDetermined from experimental data, simulation results, and the like.

Thus, the PI controller 104 determines the d-axis current deviation i_{d_err}Multiplying by d-axis proportional gain K_dpThe resulting multiplication value is offset from the d-axis current by i_{d_err}Integral value (K) of_di/s) to calculate the d-axis current FB voltage command value v_{d_fb}*。

The PI controller 104 outputs the current FB voltage instruction value v_{d_fb}Outputs the current FB voltage command value v to an initial value calculation unit 13_{d_fb}The output is to the adder 105.

The adder 105 adds the non-interference voltage value v as shown in the formula (4)_{d_dcpl}And current FB voltage command value v_{d_fb}Adding the sum to obtain a d-axis voltage command value v for current vector control_diAnd output to the control switch 3.

[ formula 4]

v_di ^*＝v_{d_dcpl} ^*+v_{d_fb} ^*···(4)

In this way, the current vector controller 1 obtains the current FB voltage command value v of the d-axis based on the torque command value T_{d_fb}Sum of non-interfering voltage values v as feed-forward compensation values for the d-axis_{d_dcpl}From which a d-axis voltage command value v of current vector control is output_di*。

Fig. 2 illustrates a d-axis voltage command value v for current vector control_diThe structure for calculating the q-axis voltage command value v_qiThe structure for performing the operation is also the same as that shown in fig. 2.

Therefore, current vector control unit 1 reduces the current components of d-axis and q-axis of the electric power supplied to electric motor 9 based on torque command value TEach deviated current FB voltage command value v_{d_fb}A and v_{q_fb}And performing operation. Then, the current vector control unit 1 compensates the calculated current FB voltage command value v_{d_fb}A and v_{q_fb}D-axis and q-axis non-interference voltage values v_{d_dcpl}A and v_{q_dcpl}Calculating d-axis and q-axis voltage command values v of current vector control_diA and v_qi*。

Further, the q-axis voltage command value v for current vector control_qiSince the description of the structure for performing the calculation is repeated, the description thereof is omitted.

Fig. 3 is a block diagram showing a configuration example of the initial value calculation unit 13 according to the present embodiment.

The initial value calculation unit 13 includes a d-axis filter 131, a d-axis adder 132, a q-axis filter 133, a q-axis adder 134, and a voltage phase calculator 135.

The d-axis filter 131 is a filter for controlling the d-axis current FB voltage command value v as the calculated value of the current vector control unit 1_{d_fb}Is passed through a low pass filter. That is, the d-axis filter 131 forms the d-axis voltage command value v_diThe feedback command value of (a) performs a filtering process of passing a low-frequency component of the feedback command value. Thereby, the d-axis voltage command value v caused by the current feedback control is adjusted_diAnd removing the pulsating component.

D-axis filter 131 of the present embodiment commands a d-axis current FB voltage v_{d_fb}The filtering process as in equation (5) is performed. In addition, τ in the formula (5)_yIs the time constant of the filter for removing the d-axis voltage command value v_diThe pulsation component is obtained from experimental data, simulation results, and the like.

[ formula 5]

The d-axis filter 131 outputs the filtered current FB voltage command value v_{d_fb_flt}Outputs to the d-axis adder 132.

d-axis addition arithmetic unit132 to the d-axis non-interference voltage value v as the calculated value of the current vector control unit 1_{d_dcpl}And the filtered current FB voltage command value v_{d_fb_flt}Add operation. The d-axis adder 132 uses the value obtained by the addition as the d-axis voltage command value v after the filtering process_{d_flt}And output to the voltage phase operator 135.

The q-axis filter 133 is a filter for making the q-axis current FB voltage command value v as the calculation value of the current vector control unit 1_{q_fb}Is passed through a low pass filter. That is, the q-axis filter 133 forms the q-axis voltage command value v_qiThe feedback command value of (a) performs a filtering process of passing a low-frequency component of the feedback command value.

The q-axis filter 133 of the present embodiment is similar to the d-axis filter 131 in that it gives a q-axis current FB voltage command value v_{q_fb}The filtering process of formula (5) is performed. Thereby, the q-axis voltage command value v caused by the current feedback control is adjusted_qiAnd removing the pulsating component. The q-axis filter 133 gives the filtered current FB voltage command value v_{q_fb_flt}The output is to the q-axis adder 134.

The q-axis adder 134 adds the q-axis non-interference voltage value v to the q-axis voltage value v as the calculated value of the current vector control unit 1_{q_dcpl}And the filtered current FB voltage command value v_{q_fb_flt}Add operation. The q-axis adder 134 uses the value obtained by the addition as the q-axis voltage command value v after the filtering process_{q_flt}And output to the voltage phase operator 135.

The voltage phase calculator 135 calculates an initial value α of the voltage phase command value based on the calculated value of the current vector control unit 1_{_flt}Operating, the initial value α of the voltage phase command value_{_flt}For initializing the voltage phase control unit 2 shown in fig. 1.

The voltage phase calculator 135 of the present embodiment is based on the d-axis and q-axis voltage command values v after the filtering process_{d_flt}A and v_{q_flt}Initial value α of voltage phase command value_{_flt}And performing operation. That is, the voltage phase calculator 135 uses the non-interference voltage value v_{d_dcpl}A andv_{q_dcpl}and the filtered current FB voltage command value v_{d_fb_flt}A and v_{q_fb_flt}And the voltage phase control section 2 is initialized.

For example, the voltage phase calculator 135 uses the d-axis and q-axis voltage command values v after the filtering process as in equation (6)_{d_flt}A and v_{q_flt}Calculates the voltage phase command value, and uses the calculated value as the initial value α_{_flt}And output to the voltage phase control section 2.

[ formula 6]

Therefore, when the detected rotational speed value N is equal to or greater than 0 (zero), that is, when the motor 9 is in the power running state, the voltage phase calculator 135 uses the expression of the upper stage of expression (6) to calculate the initial value α of the voltage phase command value_{_flt}When the detected rotation speed value N is less than 0, that is, when the motor 9 is in the regeneration state, the voltage phase calculator 135 calculates the initial value α using the following expression_{_flt}Make a calculation.

Thus, the initial value calculation unit 13 gives only the voltage command value v to the current vector control unit 1_diA and v_qiFeedback component (v) of_{d_fb}A and v_{q_fb}A) performs a low pass filtering process. Thereby, the feedforward component (v) is not changed_{d_dcpl}A and_{vq_dcpl}by applying low-pass filtering processing, it is possible to suppress control lag of the motor 9 and reliably set the voltage command value v due to current feedback control_diA and v_qiAnd removing the pulsating component.

Therefore, it is possible to avoid the initial value α set as the voltage phase command value of the voltage phase control unit 2 when the control of the motor 9 is switched from the current vector control to the voltage phase control_{_flt}Error of voltage command value v_diA and v_qiAnd excessive ripple noise.

In the present embodiment, the currents FB for the d-axis and q-axisVoltage command value v_{d_fb}A and v_{q_fb}In this case, the initial value α of the voltage phase command value can be suppressed_{_flt}Error of x.

Fig. 4 is a block diagram showing a configuration example of the voltage phase control unit 2 according to the present embodiment.

The voltage phase control unit 2 includes a voltage amplitude calculator 201, a voltage phase calculator 202, a torque estimator 203, a torque deviation calculator 204, a PI controller 205, a voltage phase addition calculator 206, and a dq-axis voltage converter 207.

The voltage amplitude calculator 201 compares a predetermined voltage amplitude command value V with a predetermined modulation factor command value M_aAnd performing operation. Here, the modulation rate command value M indicates a reference value of the modulation rate in the voltage phase control. The modulation factor in the voltage phase control is the amplitude of the fundamental component of the inter-phase voltage of the motor 9 with respect to the battery voltage detection value V_dcThe ratio of (a) to (b). The phase-to-phase voltage of the motor 9 is, for example, a voltage between U-phase and V-phase (V)_u-V_v)。

In general, the range of the modulation ratio of the voltage phase control from 0.0 to 1.0 corresponds to a normal modulation region in which an analog sine wave voltage can be generated by PWM modulation. On the other hand, a range in which the modulation factor exceeds 1.0 corresponds to an overmodulation region, and even if a pseudo sine wave is to be generated, the maximum value and the minimum value of the fundamental wave component of the inter-phase voltage are limited. For example, if the modulation ratio is increased to about 1.1, the fundamental wave component of the inter-phase voltage becomes the same waveform as the so-called rectangular wave voltage.

The voltage amplitude calculator 201 of the present embodiment detects the battery voltage from the battery voltage detection value V_dcFor the voltage amplitude command value V_aChange is made. For example, the voltage amplitude calculator 201 calculates the voltage amplitude command value V as shown in equation (7)_aMake a calculation. The voltage amplitude arithmetic unit 201 calculates the voltage amplitude command value V_aOutput to the dq-axis voltage converter 207.

[ formula 7]

The voltage phase calculator 202 performs feedforward control on the basis of the torque command value T to obtain a voltage phase FF value α indicating the phase of the voltage to be supplied to the motor 9_ffAnd performing operation. The voltage phase calculator 202 of the present embodiment uses the torque command value T, the rotation speed detection value N, and the battery voltage detection value V_dcAnd to voltage phase FF value α_ffMake a calculation.

For example, the voltage phase calculator 202 stores a predetermined phase table. In the phase table, the torque command value T, the rotation speed detection value N and the battery voltage detection value V are used as reference_dcDetermined phase of each operating point with voltage FF value α_ffCorrelation of voltage phase FF values α as a phase table_ffFor example, values of the resulting voltage phases measured in the experiment in the nominal state for each operating point of the electric motor 9 are used.

The voltage phase calculator 202 obtains a torque command value T, a rotation speed detection value N, and a battery voltage detection value V_dcWith reference to the phase table, the voltage phase FF value α associated with the operating point determined from each parameter is corrected_ffThe voltage phase operator 202 calculates the voltage phase FF value α_ffOutputs to the voltage phase adder 206.

The torque estimator 203 detects the d-axis current i_dAnd q-axis current detection value i_qTo the torque estimated value T_calAnd (6) performing operation. The torque estimator 203 stores a predetermined torque table. In the torque meter, a current detection value i is detected according to a d axis_dAnd q-axis current detection value i_qDetermined each operating point and torque estimate T_calAnd establishing association. Torque estimation value T as a torque meter_calFor example, a measured value of the torque measured experimentally for each operating point of the motor 9 determined from the dq-axis current is used.

Torque estimator203 if d-axis current detection value i is obtained_dAnd q-axis current detection value i_qWith reference to the torque table, the torque estimation value T associated with the operating point determined from each parameter is determined_calAnd (6) performing calculation. The torque estimator 203 estimates the calculated torque T_calTo the torque deviation operator 204.

The torque deviation calculator 204 compares the torque command value T with the torque estimation value T_calTorque deviation T of_errAnd (6) performing operation. The torque deviation calculator 204 of the present embodiment subtracts the torque estimation value T from the torque command value T_calThe resulting value is taken as the torque deviation T_errAnd outputs to the PI controller 205.

The PI controller 205 performs torque feedback control such that the torque estimation value T_calDeviation of torque T following torque command value T_errAnd feeds back the voltage phase command value α.

The PI controller 205 of the present embodiment is based on the torque deviation T as in equation (8)_err(＝T*-T_cal) And to voltage phase FB value α_fbPI controller 205 calculates voltage phase FB value α_fbOutputs to the voltage phase adder 206.

[ formula 8]

Furthermore, K_αpIs the proportional gain, K_αiIs the integral gain. Proportional gain K_αpAnd integral gain K_αiDetermined from experimental data, simulation results, and the like. (1/s) T in the formula (8)_errAn integrator equivalent to the PI controller 205, and (1/s) is equivalent to the torque deviation T_errThe integrated value of (2).

The PI controller 205 of the present embodiment refers to the control mode flag CNT _ F L G, and when the control mode flag CNT _ F L G indicates switching from the current vector control to the voltage phase control, the PI controller 205 refers to the initial value α of the voltage phase command value from the initial value calculation unit 13_fltTo the PI controller 205The integrator is initialized.

Specifically, the PI controller 205 sets an initial value α of the slave voltage phase command value for the integrator of the PI controller 205_fltMinus voltage phase FF value α_ffValue obtained (α)_flt*-α_ffThat is, the PI controller 205 sets the output value of the voltage phase adder 206 to the initial value α_fltIn such a way that the integral value (1/s) of the PI controller 205 is reset.

Then, the PI controller 205 sets the initial value α of the slave voltage phase command value_fltMinus voltage phase FF value α_ffValue obtained (α)_flt*-α_ffAs voltage phase FB value α_fbAnd output to the voltage phase adder 206.

The voltage phase adder 206 adds the voltage phase FF value α from the voltage phase operator 202 to the voltage phase FF value_ffPlus voltage phase FB value α_fbAnd calculates a voltage phase command value α the voltage phase adder 206 outputs the calculated voltage phase command value α to the dq-axis voltage converter 207.

The dq-axis voltage converter 207 converts the voltage phase command value α and the voltage amplitude command value V output from the voltage amplitude calculator 201 as in equation (9)_aConversion to d-axis voltage command value v_dvVoltage command value v of x and q axes_qv*。

[ formula 9]

The dq-axis voltage converter 207 converts the converted d-axis voltage command value v_dvVoltage command value v of x and q axes_qvAnd outputs the voltage command value to the control switching unit 3 as a voltage phase control voltage command value.

Thus, the voltage phase control section 2 controls the torque deviation T_errThe voltage phase command value α is changed so as to converge to zero, whereby the voltage amplitude command value V is changed even in the overmodulation region of the voltage amplitude_aIn the fixed state, the torque of the motor 9 can be changed.

When the control of the motor 9 is switched from the current vector control to the voltage phase control in accordance with the control mode flag CNT _ F L G, the voltage phase controller 2 sets the initial value α obtained based on the calculated value of the current vector controller 1_fltBy setting the voltage phase command value α, the variation in torque of the electric motor 9 when switching to the voltage phase control can be reduced.

In the present embodiment, the torque deviation T is used as a reference_errThe voltage phase command value α is changed, but the present invention is not limited to this, and for example, the voltage phase command value α may be changed in accordance with a variation in the supply current of the motor 9.

Fig. 5 is a diagram illustrating a variation in torque of the motor 9 when switching to the voltage phase control.

Fig. 5 shows a state change of the motor 9 of the present embodiment and a comparative example thereof. This comparative example shows the voltage command value v for the d-axis and q-axis as the output of the current vector control unit 1 when calculating the initial value of the voltage phase command value set for the voltage phase control unit 2_diA and v_qiThe state change of the motor 9 when the low-pass filtering process is performed as a whole.

In the comparative example of fig. 5, as shown in fig. 5(a), at time T10, the control mode flag CNT _ F L G is changed from "1" to "2".

In this case, the voltage value v is not only commanded to the d-axis and the q-axis_diA and v_qiSince the feedback component is low-pass filtered and the feedforward component is also low-pass filtered, the torque of the motor 9 is sharply reduced as shown in fig. 5 (c).

The reason why the torque variation occurs as described above is that the feedforward component is additionally subjected to the low-pass filtering process, and the deviation between the actual voltage phase of the motor 9 and the initial value of the voltage phase command value increases. In this example, as the initial value of the voltage phase command value, a value smaller than the actual voltage phase is calculated by an excessive filtering process.

On the other hand, in the present embodiment of fig. 5, only the d-axis and q-axis voltage command values v are calculated by the initial value calculation unit 13 shown in fig. 3_diA and v_qiThe feedback component of the signal is subjected to a low-pass filtering process. Therefore, when the control of the motor 9 is switched to the voltage phase control at time T0 as shown in fig. 5(a), the fluctuation in the torque of the motor 9 is reduced as shown in fig. 5 (c).

As described above, the initial value calculation unit 13 of the present embodiment sets the initial value α for the voltage phase command value_fltWhen calculating, the voltage command value v of d-axis and q-axis_diA and v_qiThe pulsating component is removed and only the feedback component is subjected to a low-pass filtering process.

Thus, the d-axis and q-axis command voltage values v caused by the current feedback control can be easily applied without excess or deficiency_diA and v_qiSince the ripple component is removed, the initial value of the voltage phase command value can be obtained with high accuracy. Therefore, it is possible to reduce the variation in torque of the motor 9 that may occur when the control of the motor 9 is switched from the current vector control to the voltage phase control.

Fig. 6 is a flowchart showing an example of processing procedures relating to the control method for the motor 9 according to the present embodiment. The processing procedure of the present embodiment is repeatedly executed in a predetermined operation cycle.

In step S1, control device 100 detects the operating state of motor 9. For example, the control device 100 obtains the torque command value T and the d-axis current detection value i_dQ-axis current detection value i_qRotation speed detection value N and battery voltage detection value V_dcAnd so on.

In step S2, the control device 100 selects control to be applied to the motor 9 based on the acquired values of the parameters at least from among the current vector control and the voltage phase control, and the control device 100 sets an identifier indicating the selected control as the control mode flag CNT _ F L G.

For example, the torque command value T or the d-axis current detection value i_dLess than or equal to gaugeWhen the threshold value is fixed, the control device 100 selects the current vector control. Then, in a state where the current vector control is selected, the torque command value T or the d-axis current detection value i_dIf the voltage exceeds the predetermined threshold, control device 100 selects voltage phase control. Further, instead of or in addition to the selection condition, control device 100 may detect a value i based on the q-axis current_qAnd a rotation speed detection value N to select the control to be applied to the motor 9.

In step S3, the control device 100 determines whether the control set by the control mode flag CNT _ F L G is current vector control or voltage phase control.

In step S4, when the control mode flag CNT _ F L G indicates current vector control, the current vector controller 1 sets the non-disturbance voltage value v to the d-axis and q-axis based on the torque command value T of the motor 9_{d_dcpl}A and v_{q_dcpl}And calculating to obtain the feedforward compensation value.

In step S5, the current vector control unit 1 obtains the current deviation of the current supplied to the motor 9 based on the torque command value T, and applies the current FB voltage command value v to the d-axis and q-axis based on the current deviation_{di_fb}A and v_{qi_fb}And calculating the feedback instruction value.

In step S6, the current vector control unit 1 instructs the voltage v to the d-axis and q-axis currents FB by the voltages v_{di_fb}A and v_{qi_fb}Adding non-interference voltage values v respectively_{d_dcpl}A and v_{q_dcpl}D-axis and q-axis voltage command values v for vector control of current_diA and v_qiAnd outputting.

In step S7, control device 100 sets d-axis and q-axis command values v_diA and v_qiConversion into three-phase command values v_u*、v_vA and v_w*. The inverter 6 is based on the three-phase voltage command value v_u*、v_vA and v_wAnd a three-phase ac voltage is supplied to the motor 9, ending a series of processing sequences relating to the control method of the motor 9.

When the control of the motor 9 is switched to the voltage phase control in step S4, the control device 100 proceeds to the process of step S8.

In step S8, control device 100 uses the feedforward compensation value and the feedback command value after the low-pass filtering process to adjust initial value α of the voltage phase command value_fltAnd performing operation. For example, as shown in fig. 3, the initial value calculation unit 13 instructs the voltage v to the current FB voltage of only the d-axis and the q-axis_{di_fb}A and v_{qi_fb}Calculating an initial value α of the voltage phase command value by performing a low-pass filtering process_flt*。

In step S9, control device 100 sets initial value α based on the voltage phase command value_fltFor example, the control device 100 sets the slave initial value α for the integral value (1/s) of the PI controller 205 shown in fig. 4_fltMinus voltage phase FF value α_ffVoltage phase FF value α_ffThe voltage phase command value is calculated based on the torque command value T.

In step S10, the voltage phase control unit 2 executes feedback control on the voltage phase command value α ″, thereby controlling the voltage phase of the d-axis and q-axis voltage command values v_dvA and v_qvAnd outputting. Then, the control device 100 proceeds to the process of step S7, and after executing the process of step S7, ends the control method of the motor 9.

According to the present embodiment of the invention, the control device 100 in the control method of the electric motor 9 executes any one of current vector control and voltage phase control for controlling the electric power supplied to the electric motor 9 in accordance with the operating state of the electric motor 9. Then, as in steps S4 to S6, the control device 100 outputs the voltage command value v of the current vector control by calculating the feedback command value and the feedforward compensation value based on the torque command value T of the electric motor 9_diA and v_qi*。

The feedback command value is a parameter indicating a voltage value of the motor 9 that reduces a deviation of a current supplied to the motor 9, and examples thereof include a d-axis current FB voltage command value v and a q-axis current FB voltage command value v_{qi_fb}A and v_{qi_fb}*. In addition, the feedforward compensation value is used for compensating the feedback instructionParameters of value, including d-axis and q-axis non-interfering voltage values v_{d_dcpl}A and v_{q_dcpl}A torsional vibration compensation value of the drive shaft, etc.

When the control of the motor 9 is switched from the current vector control to the voltage phase control as in step S9, the control device 100 initializes the voltage phase control based on the calculated value of the current vector control, and the control device 100 outputs the voltage command value v of the voltage phase control by performing the feedback control of the predetermined voltage phase command value α based on the torque command value T as in step S10_dvA and v_qv*。

Then, the control device 100 performs filtering processing for passing the low frequency component of the feedback command value with respect to the feedback command value as in step S8, and the control device 100 uses the feedforward compensation value and the filtered feedback command value to adjust the initial value α of the voltage phase command value_fltAnd performing operation.

With this configuration, it is possible to suppress a variation in torque of the motor 9 that may occur when the control of the motor 9 is switched to the voltage phase control.

In detail, according to the present embodiment, by applying the filtering process to the feedback command value, the voltage command value v caused by the current feedback control can be reliably corrected_diA and v_qiAnd removing the pulsating component. Therefore, since the influence of the ripple component can be reduced when the initial value of the voltage phase control is calculated, the initial value of the voltage phase control can be obtained with high accuracy when the control of the motor 9 is switched from the current vector control to the voltage phase control.

In addition, for example, in a situation where the rotation speed of the electric motor 9 is gradually increased, the fundamental wave component of the voltage command value immediately before switching is likely to coincide with the voltage phase command value immediately after switching, and therefore the control of the electric motor 9 can be switched to the voltage phase control without the torque of the electric motor 9 fluctuating and without the torque of the electric motor 9 having a step difference at the time of switching.

Further, even when the control of the motor 9 is switched to the voltage phase control in a situation where the torque of the motor 9 changes abruptly, the filter processing is performed only on the feedback command value, and therefore the control lag of the motor 9 due to the filter processing can be reduced.

That is, according to the present embodiment, when the control of the motor 9 is switched to the voltage phase control, the influence of the control lag of the motor 9 due to the filter processing can be reduced while reducing the variation of the torque of the motor 9 due to the current feedback control.

In addition, according to the present embodiment, as shown in fig. 4, the control device 100 bases the initial value α of the voltage phase command value_fltAnd updates the integral value of the PI controller 205 constituting the feedback control of the voltage phase control section 2.

Thus, when the control of the motor 9 is switched from the current vector control to the voltage phase control, the deviation between the voltage phase component of the voltage command value of the current vector control and the voltage phase command value of the voltage phase control can be reduced. Therefore, the variation in torque of the motor 9 generated when switching to the voltage phase control can be suppressed.

Further, according to the present embodiment, as shown in fig. 4, the voltage phase control unit 2 performs feedback control of feeding back the voltage phase command value α to the torque generated in the motor 9, and the initial value calculation unit 13 calculates the initial value α of the voltage phase command value_fltA voltage phase FF value α which is a feedforward component of the voltage phase command value α calculated by the voltage phase control unit 2 is subtracted from the voltage phase command value_ffThe subsequent reset value is set as the integral value of the PI controller 205.

In this way, the feedforward component of the voltage phase control unit 2 is taken into consideration, and therefore the voltage phase command value α calculated by the voltage phase control unit 2 and the initial value α of the voltage phase command value obtained from the calculated value of the current vector control unit 1 can be further reduced_fltThe difference of x.

While the embodiments of the present invention have been described above, the above embodiments are merely illustrative of some application examples of the present invention, and the technical scope of the present invention is not limited to the specific configurations of the above embodiments. In addition, the above embodiments may be appropriately combined.