JP2022178109A - Motor control method, and motor control device - Google Patents

Abstract

To reduce a load of arithmetic processing concerning a motor control.SOLUTION: A motor control device 20 vector-controls driving of a motor 8 by feeding back a current value determined by coordinate-converting a detection value of AC flowing through each phase of the motor 8 from a fixed coordinate system into a rotary coordinate system. Further, a motor control device 20 comprises: an inverter 6 for converting a DC power into an AC power, and supplying the AC power to the motor 8; a coordinate converter 10 for converting the detection value of the AC into a current value in the rotary coordinate system via coordinate conversion; a phase delay correction device 14 for correcting the DC value in the rotary coordinate system based on a phase delay amount of a phase current of each phase of the motor 8, using a preset correction value; and a control part (a current voltage converter 1, a current control device 2, a coordinate converter 3, and a PWM converter 4) for controlling the inverter 6 based on the corrected current value in the rotary coordinate system, and an output target value of the motor 8 input from outside.SELECTED DRAWING: Figure 1

Description

The present invention relates to a motor control method and a motor control device for controlling driving of a polyphase motor.

Conventionally, there is a technique for controlling the driving of a polyphase motor by compensating for the error (phase delay of the phase current of each phase of the polyphase motor) of the current sensor that detects the alternating current flowing through the coils of the polyphase motor. For example, using a correction value consisting of a plurality of parameters set based on the phase delay amount of the phase current of each phase of a polyphase motor, the phase current of each phase in the fixed coordinate system is converted into a current value in the rotating coordinate system. A technique for doing so has been proposed (see Patent Document 1, for example).

JP 2012-39716 A

In the above-described prior art, a coordinate converter that converts the phase current of each phase in the fixed coordinate system into a current value in the rotating coordinate system performs a correction operation using a correction value composed of the plurality of parameters described above. As a result, the computation in the coordinate converter becomes complicated, the amount of computation increases, and the computation processing load related to motor control increases.

SUMMARY OF THE INVENTION An object of the present invention is to reduce the load of arithmetic processing related to motor control.

One aspect of the present invention provides vector control for driving the multiphase motor by feeding back current values obtained by coordinate transformation of detected values of alternating current flowing in each phase of a multiphase motor from a fixed coordinate system to a rotating coordinate system. This is a motor control method for In this motor control method, a correction value preset based on the phase delay amount of the phase current of each phase of the multiphase motor is used to correct the current value in the rotating coordinate system obtained by the coordinate transformation. Based on the obtained current value of the rotating coordinate system and the output target value of the multiphase motor input from the outside, the power converted from DC power to AC power and supplied to the multiphase motor is controlled.

According to the present invention, it is possible to reduce the load of arithmetic processing related to motor control.

FIG. 1 is a block diagram showing a configuration example of a motor control device. FIG. 2 is a diagram showing waveforms of both the phase current actually flowing through each phase of the inverter and the motor and the phase current detected by the current sensor. FIG. 3 is a diagram showing dq-axis current waveforms both when correction is performed by the phase delay corrector and when correction is not performed by the phase delay corrector. FIG. 4 is a diagram showing the relationship between the current value in the rotating coordinate system converted by the coordinate converter and the corrected current value corrected by the phase delay corrector. FIG. 5 is a block diagram showing a configuration example of a motor control device according to the second embodiment. FIG. 6 is a diagram showing a correction value table held by the phase delay corrector.

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

[First embodiment]
[Configuration example of motor control device]
FIG. 1 is a block diagram showing a configuration example of the motor control device 20. As shown in FIG.

The motor control device 20 includes a current-voltage converter 1, a current controller 2, coordinate converters 3 and 10, a PWM (Pulse Width Modulation) converter 4, a battery 5, an inverter 6, and a current sensor 7. , a motor 8 , a magnetic pole position detector 9 , a revolution calculator 11 , an LPF (Low Pass Filter) 12 , a gain corrector 13 and a phase delay corrector 14 . The motor control device 20 performs vector control of the drive of the motor 8 by feeding back the current values obtained by coordinate-converting the detected values of the AC current flowing through each phase of the motor 8 from the fixed coordinate system to the rotating coordinate system. It is an example of a motor control device.

The current-voltage converter 1 receives a torque command value (T ^* ) externally input as a target output value of the motor 8, an angular frequency (ω) of the motor 8, which is the output of the rotation speed calculator 11, and A voltage (V _dc ) is input from the battery 5 to the inverter 6 . The current-voltage converter 1 outputs a dq current command ( _id ^* , iq*) and a dq-axis non-interference voltage command using a torque command value (T ^* ), an angular frequency ( _ω ⁾ , and a voltage ( _Vdc ) as indices. A map for outputting the values (V _d ^* _dcpl, V _q ^* _dcpl) is stored, and the current-voltage converter 1 refers to the map to obtain the input torque command value (T ^* ) Calculate dq-axis current command values ( _id ^* , _iq ^* ) and dq-axis non-interference voltage command values ( _Vd ^* _{_dcpl} , _Vq ^* _dcpl) corresponding to angular frequency (ω) and voltage (Vdc) and output. Here, the dq axes indicate the components of the rotating coordinate system. Regarding the dq-axis non-interference voltage command values (V _d ^* _dcpl, V _q ^* _dcpl), when a current flows in the d-axis and the q-axis, an interference voltage ωLdid is generated on the d-axis and ωLqiq is generated on the q-axis. The dq-axis non-interference voltage command values ( _Vd ^* _dcpl, _Vq ^* _dcpl) are voltages for canceling out the interference voltages. Ld indicates reactance on the d-axis, and Lq indicates reactance on the q-axis.

The LPF 12 receives the dq-axis non-interference voltage command values (V _d ^* _dcpl, V _q ^* _dcpl), cuts the high frequency band, and outputs voltage command values (V _d ^* _dcpl_flt, V _q ^* _dcpl_flt).

The current controller 2 controls dq-axis current command values ( _id ^* , _iq ^* ), voltage command values ( _Vd ^* _dcpl_flt, _Vq ^* _dcpl_flt), and corrected current values ( _{id_co} , _{iq_co} ) to be described later. are input, control calculation is performed, and dq-axis voltage command values (V _d ^* , V _q ^* ) are output.

The coordinate converter 3 inputs the dq-axis voltage command values (V _d ^* , V _q ^* ) and the detection value θ of the magnetic pole position detector 9, and uses the following equation (1) to convert dq Axis voltage command values (V _d ^* , V _q ^* ) are converted into voltage command values (V _u ^* , V _v ^* , V _w ^* ) of the u, v, and w axes of the fixed coordinate system.

The _PWM converter 4 generates drive signals ( _{D uu} ^{* ,} D _ul ^{* ,} D _vu ^{* ,} _{D vl} ^* , _Dwu ^* , _Dwl ^* ) and output to the inverter 6.

A battery 5 is a DC power supply including a secondary battery.

The inverter 6 is composed of a three-phase inverter circuit in which a plurality of circuits in which switching elements such as MOSFETs and IGBTs are connected in pairs are connected. Output signals (D _uu ^* , D _ul ^* , D _vu ^* , D _vl ^* , D _wu ^* , D _wl ^* ) of the PWM converter are input to each switching element. Then, the switching operation of the switching elements converts the DC voltage of the DC power supply into AC voltages (V _u , V _v , V _w ), which are input to the motor 8 . Also, when the motor 8 operates as a generator, the inverter 6 converts the AC voltage output from the motor 8 into a DC voltage and outputs the DC voltage to the battery 5 . The battery 5 is thereby charged.

The current sensor 7 is connected between the inverter 6 and the motor 8 and detects three-phase AC phase currents (i _u , _iv , i _w ). The current sensor 7 is composed of a plurality of sensors, and the plurality of sensors are connected to each phase.

Motor 8 is a multiphase motor and is connected to inverter 6 . Also, the motor 8 operates as a generator.

A magnetic pole position detector 9 is provided in the motor 8 to detect the position of the magnetic poles of the motor 8, and outputs a detected value (θ) to the coordinate converters 3 and 10 and the revolution calculator 11. FIG.

The rotation speed calculator 11 calculates the angular frequency (ω) of the motor 8 from the detected value (θ) of the magnetic pole position detector 9, and outputs the calculation result (the measured value of the angular frequency (ω) of the motor 8). .

The gain correction unit 13 performs gain correction on the phase currents (i _u , _iv , i _w ) of each phase, and outputs the current values (i _{u_gain} , _{iv_gain} , i _{w_gain} ) after gain correction to the coordinate converter 10 . do. Since the current sensor 7 is a plurality of sensors, variations in the production process occur for each phase. Therefore, in the first embodiment, a gain correction unit 13 is provided between the current sensor 7 and the coordinate converter 10 to correct the phase current of each phase.

The current values ( _{iu_gain} , _{iv_gain} , _{iw_gain} ) corrected by the gain correction unit 13 are represented by the following equation (2).

However, k _u , k _v , and k _w represent respective gain coefficients of the u, v, and w phases, and are coefficients that are set in advance according to the current sensor 7 connected to each phase.

When the current sensors 7 are provided only for the u-phase and v-phase, the _{w- phase} current is calculated by the following equation ( 3).

The coordinate converter 10 is a _control unit that _performs three- _phase to two-phase conversion. (4), the current values ( _{iu_gain} , _{iv_gain} , _{iw_gain} ) in the fixed coordinate system are converted into the current values ( _id , _iq ) in the rotating coordinate system.

The phase delay corrector 14 sets correction values (a, b) based on the phase delay amount of the current sensor 7 of each phase, and calculates the current values (i _d , i _q ) into corrected current values ( _{id_co} , i _{q_co} ).

Here, the correction values (a, b) set by the phase delay corrector 14 will be described. The phase delay amount (degrees) of the detected current varies among the current sensors 7 of each phase due to variations during production. Therefore, in the _first embodiment, the correction _values ( _a , b). The phase delay amounts (u _dly , v _dly , w _dly ) of the current sensors 7 for each phase are values that can be obtained in advance according to variations during production. Thus, the correction values (a, b) are coefficients set based on the phase delay amounts (u _dly , v _dly , w _dly ) of the current sensors 7 of each phase.

When the current sensors 7 are provided only for the u-phase and the v-phase, the correction values (a, b) are derived using the following equation (7).

In this way, the correction values (a, _b ) are the average value ( _{u dly} +v _dly +w _dly /3 _{or udly} +v _dly /2).

FIG. 4 shows the current values ( _id , _iq ) in the rotating coordinate system converted by the coordinate converter 10 and the corrected current values ( _{id_co} , _{iq_co} ) corrected by the phase lag corrector 14. FIG. 4 is a diagram showing relationships;

FIG. 4 shows an example in which the vertical axis is the q-axis and the horizontal axis is the d-axis. A dotted line E1 indicates the current values (i _d , i _q ) in the rotating coordinate system converted by the coordinate converter 10 using the above equation (4). A solid line E2 indicates the corrected current values ( _{id_co} , _{iq_co} ) corrected by the phase delay corrector 14 using the above equation (5). In other words, the solid line E2 indicates the true current values ( _{id_co} , _{iq_co} ) after dq axis conversion.

Also, the angle R1 indicates the delay amount (delay angle) of the current values (i _d , i _q ) in the rotating coordinate system. In other words, the angle R1 is a value corresponding to the average value (u _dly +v _dly +w _dly /3 or _udly +v _dly /2) of the phase delay amounts (u _dly , v _dly , w _dly ) in the fixed coordinate system. .

As shown in FIG. 4, the phase delay corrector 14 corrects the delay angle R1 of the current values ( _id , _iq ) in the rotating coordinate system so that it returns to the true angle. For example, it is possible to correct by rotational transformation using a two-dimensional rotation matrix for rotating by an angle R1 about the origin.

That is, the correction value of the first embodiment is linear with respect to the current values (i _d , i _q ) of the rotating coordinate system determined to cancel the phase delay amounts (u _dly , v _dly , w _dly ) of the fixed coordinate system. Defined as a transformation (rotational transformation). In particular, in the first embodiment, in constructing the correction value, the average value of each component of the phase delay amount (u _dly , v _dly , w _dly ) in the fixed coordinate system is used. reducing the number.

More specific description will be given. If an attempt is made to determine a correction value (linear transformation) that cancels out the phase delay amounts (u _dly , v _dly , w _dly ) of the fixed coordinate system without using the average value, each element (2× Each component of the phase delay amount (u _dly , v _dly , w _dly or u _dly , v _dly ) enters irregularly into each component of the two matrices). That is, the effect of the phase delay independently determined for each phase (u-axis, v-axis, w-axis) on the fixed coordinate system appears as a mutual phase shift between the d-axis and the q-axis on the rotating coordinate system. This must be taken into account when defining the linear transformation.

Therefore, the linear transformation that corrects the current values (i _d , i _q ) in the rotating coordinate system is a linear transformation that assumes that each element is an independent parameter (i.e., u _dly , v _dly , and/or or as a 2×2 matrix defined by four independent components that are functions of _{w_dly} ).

On the other hand, in the first embodiment, the average value of each component of the phase delay amount, which is the three parameters in the fixed coordinate system, represents the phase angle change of the current values (i _d , i _q ) in the rotating coordinate system. By reducing it to a single parameter, we reduce the number of practical parameters for constructing the linear transformation. In particular, in correcting the phase lag, it can be considered that the magnitude of the current values ( _id , _iq ) (current vector norm) is maintained. i _d , i _q ) can be defined as a rotational transformation (equation (5) and equation (6) above) that shifts (advances) the phase of id and i q by the average value. Therefore, the correction value can be determined by two parameters (a, b) corresponding to the two main components (sin and cos) that constitute the rotational transformation.

Furthermore, as described above, the phase lag of the current sensor 7 for each phase is a value fixed in advance due to variations in the production stage, and the correction values (a, b) are uniquely determined. Therefore, the correction values (a, b) can be calculated and obtained in advance. In addition, the correction values (a, b) calculated in advance can be held by the phase delay corrector 14 and used. Then, the phase delay corrector 14 uses the held correction values (a, b) to correct the phase delay of the current sensor 7 of each phase according to the above equation (5).

Further, as described above, in the first embodiment, the correction values (a, b) made up of two parameters are set in advance, and the current value after the three-phase to two-phase conversion by the coordinate converter 10 is calculated as described above. Calculation of expression (5) is performed. In addition, when performing phase delay correction (for example, the correction described in Japanese Patent Application Laid-Open No. 2012-39716) in the three-phase to two-phase conversion process by the coordinate converter 10, the matrix of 2 rows and 3 columns shown in the above equation (4) For the six elements of , it is necessary to use six parameters as correction values. For this reason, the correction requires complicated arithmetic processing for the correction in the coordinate converter 10 . On the other hand, in the first embodiment, the current value after the three-phase to two-phase conversion by the coordinate converter 10 is corrected using the two parameters (a, b) as correction values. Processing can be reduced. That is, since there is no need to perform phase delay correction in the three-phase to two-phase conversion processing by the coordinate converter 10, there is no need to perform complicated arithmetic processing for correction in the coordinate converter 10. FIG. Further, since correction calculation is performed using two parameters (a, b) as correction values, complicated calculation processing can be reduced, and the load of calculation processing related to motor control can be reduced. In addition, since correction is performed using the correction values (a, b) set based on the phase delay amount (u _dly , v _dly , w _dly ) of the current sensor 7 of each phase, the phase of the current sensor 7 can be accurately corrected. delay can be compensated.

[Current waveform example]
Next, a dq-axis current waveform when correction is performed by the phase delay corrector 14 and a dq-axis current waveform when no correction is performed will be described with reference to FIGS.

FIG. 2 is a diagram showing waveforms of both the phase current actually flowing through each phase of the inverter 6 and the motor 8 and the phase current detected by the current sensor 7. As shown in FIG. Waveforms a1 to a3 represent phase currents actually flowing through the u, v, and w phases, respectively, and waveforms b1 to b3 represent phase currents detected by the current sensor 7 in the u, v, and w phases.

FIG. 3 is a diagram showing dq-axis current waveforms when correction is performed by the phase delay corrector 14 and when correction by the phase delay corrector 14 is not performed. Waveforms c1 and c2 show the dq-axis currents without correction, and waveforms d1 and d2 show the dq-axis currents with correction.

As shown in FIG. 2, it can be confirmed that the phase current actually flowing through each phase does not match the phase current detected by the current sensor 7, and a phase lag occurs in each phase. Further, as shown in FIG. 3, the dq-axis current pulsates without correction, and it can be confirmed that the pulsation is suppressed in the dq-axis current with correction. That is, according to the first embodiment, by correcting the phase lag in each phase, as shown in FIG. be able to.

Further, as described above, when the phase delay in each phase is not taken into consideration, the phase currents of the dq axes of the rotating coordinate system are calculated by performing three-phase to two-phase conversion using the above equation (4). be able to. However, if the current sensors 7 are provided for each phase in order to detect the current of each phase, a phase delay occurs between the sensors. Therefore, in the first embodiment, instead of directly using the values (phase currents of the dq axes of the rotating coordinate system) that have undergone three-phase-to-two-phase conversion using the above equation (4), the values that have undergone three-phase-to-two-phase conversion A corrected value is used. That is, after setting the coefficients (correction values (a, b)) based on the phase delay of each phase, the values obtained by correcting the phase currents of the dq axes of the rotating coordinate system using the above equation (5). use.

Thus, in the first embodiment, the phase delay amount (u _dly , v _dly , w _dly ) of the phase current of each phase is set, and the correction amount based on those values (u _dly , v _dly , w _dly ) (a, b) are set, and the correction values (a, b) are used to correct the phase currents of the dq axes of the rotating coordinate system. As a result, the current of each of the three phases is detected by the current sensor 7, and if a phase lag occurs between the phases, the feedback control is performed using the phase lag corrected value of the current value after the three-phase to two-phase conversion. It can be performed. As a result, feedback control can be performed with high accuracy, and appropriate vector control can be realized by the feedback control.

Thus, the motor control device 20 is connected to the motor 8 (an example of a polyphase motor) and includes an inverter 6 (an example of power conversion means) that converts DC power into AC power, and at least two phases of the motor 8. a current sensor 7 (an example of a current detecting means) for detecting each current; A coordinate converter 10 (an example of coordinate conversion means) to be converted and a phase delay correction value (a, b) of the phase current of each phase of the motor 8 are respectively set, and the rotating coordinate system converted by the coordinate converter 10 is set. Based on the phase delay corrector 14 (an example of phase delay correcting means) for correcting the current, the current in the rotating coordinate system corrected by the phase delay corrector 14, and the output target value of the motor 8 input from the outside. , a current-voltage converter 1 for controlling an inverter 6, a current controller 2, a coordinate converter 3 and a PWM converter 4 (an example of control means). The motor control device 30 also includes a rotation speed calculator 11 (an example of rotation speed detection means) that detects the rotation speed of the motor 8 (angular frequency (ω) of the motor 8). Further, the phase delay compensator 14 sets a plurality of correction values (a, b) corresponding to the current in the rotating coordinate system based on the phase delay amount of each phase of the motor 8, and the plurality of correction values (a, b ) is used to correct the current in the rotating coordinate system.

[Configuration and effects of the first embodiment]
In the motor control method according to the first embodiment, the detected value of the alternating current flowing in each phase of the motor 8 (an example of a multiphase motor) is coordinate-transformed from the fixed coordinate system to the rotating coordinate system, and the current value obtained is fed back. This is a motor control method in which the driving of the motor 8 is vector-controlled. In this motor control method, the correction values (a, b) preset based on the phase delay amounts (u _dly , v _dly , w _dly ) of the phase currents of the respective phases of the motor 8 are used to obtain by coordinate transformation. Based on the corrected current value of the rotating coordinate system and the output target value of the motor 8 input from the outside, DC power is converted into AC power to power the motor Controls the power supplied to 8.

According to such a motor control method, the current values after three-phase to two-phase conversion by the coordinate converter 10 are calculated in advance based on the phase delay amounts (u _dly , v _dly , w _dly ) of the phase currents in the fixed coordinate system. Correction calculation is performed using the set correction values (a, b). In this manner, the number of parameters used for calculation is reduced by performing correction using predetermined correction values (a, b) on the premise that the current value in the rotating coordinate system has fewer coordinate components than in the fixed coordinate system. can do. As a result, complicated arithmetic processing can be reduced, and the load of arithmetic processing related to motor control can be reduced. Further, since correction is performed using the correction values (a, b) set based on the phase delay amounts (u _dly , v _dly , w _dly ) of the phase currents of the respective phases of the motor 8, the correction values (a, Since the influence of the phase delay of the phase current can be properly reflected in b), the phase delay of the current sensor 7 can be corrected with high accuracy.

Further, in the motor control method according to the first embodiment, the correction values (a, b) are phase delay amounts (u _dly , v _dly , w _dly ) is set based on the average value of each component u _dly , v _dly , w _dly . That is, the phase delay corrector 14 sets the phase delay correction values (a, b) based on the average value of the phase delay amount of the phase current of each phase of the motor 8 . For example, when the current sensor 7 is composed of sensors provided for each of the three phases, using the above equation (6), based on the average value of the phase delay amount (u _dly +v _dly +w _dly /3) Correction values (a, b) are set. Further, when the current sensor 7 consists of sensors provided only for the u-phase and the v-phase, using the above equation (7), based on the average value of the phase delay amount (u _dly +v _dly /2) Correction values (a, b) are set.

According to such a motor control method, the current value of the rotating coordinate system can be corrected using the correction values (a, b) set based on the average value of the phase delay amounts. can improve the accuracy of phase delay correction.

In addition, the motor control device 20 according to the first embodiment performs coordinate transformation of the detected value of the alternating current flowing in each phase of the motor 8 (an example of a multiphase motor) from the fixed coordinate system to the rotating coordinate system. It is a motor control device that feeds back a value and vector-controls the driving of the motor 8 . The motor control device 20 also includes an inverter 6 (an example of a power conversion unit) that converts DC power into AC power and supplies it to the motor 8, and a coordinate system that converts the detected value into a current value in a rotating coordinate system by coordinate conversion. A phase delay corrector that corrects current values in the rotating coordinate system using a converter 10 (an example of a coordinate conversion unit) and a correction value preset based on the amount of phase delay of the phase current of each phase of the motor 8. 14 (an example of a correction unit), a current-voltage converter 1 that controls the inverter 6 based on the corrected current value of the rotating coordinate system, and the output target value of the motor 8 input from the outside, and a current controller. 2, a coordinate converter 3 and a PWM converter 4 (an example of a control unit).

According to such a motor control device 20, a specific device configuration suitable for use of the motor control method described above is realized.

[Second embodiment]
In the first embodiment, an example is shown in which the phase delay amount of the current sensor 7 does not depend on the angular frequency (ω) of the motor 8 . In the second embodiment, an example in which the phase delay amount of the current sensor 7 depends on the angular frequency (ω) of the motor 8 is shown. Since the second embodiment is a modified example of the first embodiment, part of the description of the parts common to the first embodiment will be omitted.

[Configuration example of motor control device]
FIG. 5 is a block diagram showing a configuration example of the motor control device 30. As shown in FIG. It should be noted that the motor control device 30 is a modified example of a part of the motor control device 20 shown in FIG. is different. Except for this point, the motor control device 30 is the same as the motor control device 20 shown in FIG. 1, so in FIG. We omit these descriptions. Note that the angular frequency (ω) of the motor 8 is obtained by the rotation speed calculator 11 as shown in the first embodiment.

The phase delay corrector 15 sets the correction values (a, b) based on the angular frequency (ω) of the rotation speed calculator 11 and the phase delay amount of the current sensor of each phase, and uses the above equation (5). to convert the current values ( _id , _iq ) in the rotating coordinate system into corrected current values ( _{id_co} , _{iq_co} ). A method of calculating the correction values (a, b) according to the angular frequency (ω) of the motor 8 will be described in detail with reference to FIG.

FIG. 6 is a diagram showing a correction value table held by the phase delay corrector 15. As shown in FIG. In the correction value table shown in FIG. 6, the angular frequency (ω) of the motor 8 and the correction values (a, b) are stored in association with each other.

Now, the correction values (a, b) stored in the correction value table shown in FIG. 6 will be described. As shown in the first embodiment, the phase delay amount (degrees) of the detected current varies among the current sensors 7 of each phase due to variations during production. Further, when the phase delay amount of the current sensor 7 depends on the angular frequency (ω) of the motor 8, the phase delay amount (u _dly , v _dly , w _dly ) are different. For this reason, in the second embodiment, based on the phase delay amount (u _dly , v _dly , w _dly ) of the current sensor 7 of each phase according to the angular frequency (ω) of the motor 8, Equation (6) is used to obtain the correction values (a, b) for each angular frequency (ω) of the motor 8 . When the current sensors 7 are provided only for the u-phase and the v-phase, the correction values (a, b) are obtained using the above-described equation (7), as in the first embodiment.

For ease of explanation, FIG. 6 shows an example in which the correction values (a, b) are obtained for the angular frequency (ω) of the motor 8 in 500 units. That is, in the correction value table shown in FIG. 6, the values of the angular frequency (ω) of the motor 8 every 500 “0, 500, 1000, . ) “(a0, b0) (a500, b500), . . .” are stored.

Further, since each correction value (a, b) is uniquely determined with respect to the angular frequency (ω) of the motor 8, each value in the correction value table shown in FIG. 6 can be calculated in advance. . Therefore, the correction value table shown in FIG. 6 can be held by the phase delay corrector 15 and used. Then, the phase delay compensator 15 refers to the correction value table shown in FIG. 6 to set the correction values (a, b) corresponding to the angular frequency (ω) of the motor 8. Based on this, the phase delay of the current sensor 7 of each phase is corrected. Thereby, the phase delay corrector 15 can appropriately correct the phase delay occurring in the current sensor 7 of each phase in consideration of the angular frequency (ω) of the motor 8 .

As described above, in the second embodiment as well, by setting a correction value table in which the correction values (a, b) made up of two parameters are stored in advance, the calculation using the above-described equation (5) can be performed to obtain accuracy. The phase lag of the current sensor 7 can be corrected well. Also in the second embodiment, by performing correction by the phase delay corrector 15, as shown in FIG. can be done.

Thus, in the second embodiment, the phase delay corrector 15 uses the phase delay correction values (a, b ).

Here, using the correction value table shown in FIG. 6, table lookup for obtaining two correction values (a, b) based on the angular frequency (ω) of the motor 8 obtained by the rotation speed calculator 11 will be described. do.

For example, among the angular frequency values (0, 500, 1000, . . . ) stored in the correction value table shown in FIG. is present, use the correction value (a,b) associated with its corresponding value. For example, when the angular frequency (ω) of the motor 8 is 500, (a500, b500) is used as the correction values (a, b). Further, when the angular frequency (ω) of the motor 8 is 2500, (a2500, b2500) is used as the correction values (a, b).

On the other hand, among the angular frequency values (0, 500, 1000, . . . ) stored in the correction value table shown in FIG. does not exist, the correction amount (a, b) is calculated using linear interpolation.

For example, it is assumed that the angular frequency (ω) of the motor 8 obtained by the rotation speed calculator 11 is 300. In this case, two angular frequency (ω) values (0, 500, 1000, . 0,500), the correction amount (a, b) is calculated using the following equation (8). X1 indicates correction values (a0, b0) corresponding to an angular frequency (ω) value of 0, and X2 indicates correction values (a500, b500) corresponding to an angular frequency (ω) value of 500. Also assume that m+n=500, m is a value of 300 between 0 and 300, and n is a value of 200 between 300 and 500.
X12=(X1·n+X2·m)/(m+n) (8)

Specifically, when calculating the correction amount a, the phase delay corrector 15 calculates X12 in Equation (8) with X1=a0, X2=a500, n=200, and m=300. Let the calculated X12 be the correction amount a. When calculating the correction amount b, the phase delay corrector 15 calculates X12 by setting X1=b0, X2=b500, n=200, and m=300 in equation (8). Let X12 be the correction amount b.

Here, the correction calculation of the comparative example will be described. Here, a comparative example (for example, Patent Document 1) is assumed in which six elements of the two-row, three-column matrix shown in the above equation (4) are corrected using six parameters as correction values. Also in this comparative example, it is assumed that the angular frequency (ω) of the motor and the correction values (six parameters) are stored in association with the correction value table. Also in this comparative example, when the value of the angular frequency (ω) of the motor does not exist among the values of the angular frequency (ω) (for example, 0, 500, 1000, . . . ) stored in the correction value table, calculates the correction amount (six parameters) using linear interpolation.

In this comparative example, if the angular frequency (ω) of the motor does not exist in the angular frequency (ω) of the correction value table, a parameter (correction value) corresponding to the angular frequency (ω) of the motor is set. Table lookup obtained from the correction value table is required for six parameters. That is, in this comparative example, six table lookups are required for correction calculation. This table lookup requires operations of two additions, two multiplications, and one division, as shown in the above equation (8). That is, five operations (two additions, two multiplications, and one division) are required for one table lookup.

As described above, in the comparative example, the detected value of each phase including the error detected by the current sensor provided for each phase of the multiphase motor is corrected for the error corresponding to the detected value of each phase. , the coordinates are transformed into current components in the dq coordinate system. For this reason, the number of parameters used for error correction increases, and the amount of calculation for error correction increases. For example, for a 3-phase motor, 6 parameters need to be used, as described above. In other words, in the comparative example, the phase delay of the current of each phase of the multiphase motor is corrected by a coordinate converter that converts from the fixed coordinate system to the rotating coordinate system, and six parameters are looked up in a table during the coordinate conversion. configuration. As a result, the calculations in the coordinate converter become complicated, the amount of calculation increases, and the calculation processing load of the coordinate converter increases.

In contrast, in the second embodiment, if the value of the angular frequency (ω) of the motor 8 does not exist in the angular frequencies (ω) of the correction value table, the correction value (a , and b) require table pulling. That is, in the second embodiment, two table lookups are required for correction calculation. However, in the second embodiment, the correction values (a, b) obtained by looking up the table require arithmetic processing using the above equation (5). 4 multiplications) are required.

Here, it is assumed that addition, subtraction, multiplication, and division are set to 1 as a calculation amount coefficient when comparing the calculation amounts of the second embodiment and the comparative example. In this case, one table lookup requires five operations (two additions, two multiplications, and one division). As described above, in the comparative example, six table lookups are required for the correction calculation, so the calculation amount of the correction calculation in the comparative example is 30 (=5×6) or more. On the other hand, in the second embodiment, two table lookups and six operations (two additions and subtractions, four multiplications) for the correction values (a, b) composed of two parameters obtained by the table lookups are performed. is required for the correction calculation, the calculation amount of the correction calculation in the second embodiment is 16 (=5×2+1×6). As described above, in the comparison using the calculation amount coefficient described above, the second embodiment can reduce the calculation amount required for the correction calculation by about 50%. As described above, in the second embodiment, the same correction as in the comparative example can be performed even if the amount of calculation is reduced by about 50%, so the amount of correction calculation (calculation load) can be greatly reduced.

[Configuration and effects of the second embodiment]
In the motor control method according to the second embodiment, the correction values (a, b) are the phase delay of the phase current of each phase of the motor 8 (polyphase motor) according to the angular frequency (an example of the rotation state) of the motor 8 (polyphase motor). The quantities (u _dly , v _dly , w _dly ) are set for each angular frequency of the motor 8 based on their average value. For example, as shown in FIG. 6, the correction values (a, b) “(a0, b0) (a500, b500), . set.

According to such a motor control method, correction is performed using appropriate correction values (a, b) according to the angular frequency of the motor 8, so the phase delay of the current sensor 7 can be corrected with high accuracy. Further, the same correction as in the comparative example described above can be performed even if the amount of calculation is reduced, and the amount of correction calculation (calculation load) can be greatly reduced.

Further, in the motor control method according to the second embodiment, based on the angular frequency of the motor 8 (an example of a multiphase motor) and the average value of the phase delay amount of the phase current of each phase of the motor 8 according to the angular frequency, Using a correction value table (an example of a table) in which the correction values (a, b) set in the above are stored in association with each angular frequency, the current value in the rotating coordinate system is corrected.

According to such a motor control method, since the correction value table is used to correct the current value in the rotating coordinate system, correction is performed using appropriate correction values (a, b) according to the angular frequency of the motor 8. It can be carried out.

Further, in the motor control method according to the second embodiment, the angular frequency stored in the correction value table and the angular frequency measurement value of the motor 8 (an example of the multiphase motor) obtained by the rotation speed calculator 11 are is used to calculate a correction value (a, b) consisting of two parameters corresponding to the measured value, and the correction value (a, b) is used to correct the current value in the rotating coordinate system. For example, the correction amount (a, b) can be calculated by linear interpolation using Equation (8) described above.

According to such a motor control method, it is possible to calculate the correction values (a, b) composed of two parameters corresponding to the measured values of the angular frequency of the motor 8 by linear interpolation using the correction value table. , appropriate correction values (a, b) corresponding to the angular frequency of the motor 8 can be used for correction.

Although the embodiments of the present invention have been described above, the above embodiments merely show a part of 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. do not have.

The two motor control methods described below are also included in the scope of matters described at the time of filing of this specification.

In the first motor control method,
Correction values set based on the phase delay amounts (u _dly , v _dly , w _dly ) of the phase currents (i _{u_gain} , _{iv_gain} , i _{w_gain} ) of each phase of the motor 8 are applied to a fixed coordinate system (especially three-phase coordinates system) so that the phase delay amounts (u _dly , v _dly , w _dly ) of the phase currents (i _{u_gain} , _{iv_gain} , i _{w_gain} ) in the rotating coordinate system (especially the d-q axis coordinate system) are canceled. _d 1 , i _q ) are defined as a plurality of parameters (for example, each element of a 2×2 matrix) constituting a transformation on a rotating coordinate system. For example, as shown in FIG. 4, each element of a two-dimensional rotation matrix for rotating by an angle R1 around the origin can be defined as a plurality of parameters.

As a result, the correction values for correcting the current values (i _d , i _q ) in the rotating coordinate system so as to cancel the phase delay amounts (u _dly , v _dly , w _dly ) in the phase currents in the fixed coordinate system are It can be determined by the number of parameters required for the transformation (especially linear transformation) defined by the system (especially four or less in the dq axis coordinate system). Therefore, the calculation load is reduced compared to the case where the phase delay amounts (u _dly , v _dly , w _dly ) are corrected as they are for the phase currents (i _{u_gain} , _{iv_gain} , i _{w_gain} ) in the fixed coordinate system. be able to.

In the second motor control method, on the premise of the first motor control method,
Based on each component u _dly , v _dly , and w _dly of the phase delay amount in the fixed coordinate system, the phase angle change of the current values ( _id , i _q ) in the rotating coordinate system caused by the phase delay amount is expressed as a single parameter. is obtained as the average value u _dly +v _dly +w _dly /3. Then, the correction value is used to shift the phase of the current values ( _id , _iq ) in the rotating coordinate system in the direction of canceling out the average value u _dly +v _dly +w _dly /3, which is the phase angle change on the rotating coordinate system. are defined as two parameters (a, b) that constitute the rotation transformation (coefficient on the right side of equation (5)). For example, as shown in FIG. 4, a two-dimensional rotation matrix for rotating an angle R1 around the origin can be set using two parameters (a, b) for each element. (a, b) can be defined.

Thereby, the correction value can be determined by two parameters (a, b) corresponding to two main components (sin and cos) constituting the rotational transformation. As a result, the number of parameters used for correction can be further reduced, and the computational load can be further reduced. Note that the single parameter representing the phase angle change of the current values (i _d , i _q ) in the rotating coordinate system is not limited to the average value of each component of the phase delay amount in the fixed coordinate system. Other values that can be calculated from the respective components (for example, statistics other than the average value such as the median value) may be used within the realizable range.

1 current-voltage converter, 2 current controller, 3, 10 coordinate converter, 4 PWM converter, 5 battery, 6 inverter, 7 current sensor, 8 motor, 9 magnetic pole position detector, 11 revolution calculator, 12 LPF , 13 gain correction section 14, 15 phase delay corrector 20, 30 motor control device

Claims (8)

A motor control method for vector-controlling the driving of a polyphase motor by feeding back current values obtained by coordinate-converting detected values of alternating current flowing in each phase of a polyphase motor from a fixed coordinate system to a rotating coordinate system. hand,
correcting the current value of the rotating coordinate system obtained by the coordinate transformation using a correction value preset based on the phase delay amount of the phase current of each phase of the multiphase motor;
Based on the corrected current value of the rotating coordinate system and the output target value of the multiphase motor input from the outside, power converted from DC power to AC power and supplied to the multiphase motor is controlled. ,
motor control method. The motor control method according to claim 1,
wherein the correction value is set based on an average value of the phase delay amounts in the fixed coordinate system;
motor control method. The motor control method according to claim 1 or 2,
The correction value is set for each rotation state of the polyphase motor based on the phase delay amount corresponding to the rotation state of the polyphase motor.
motor control method. The motor control method according to claim 3,
the rotational state is the angular frequency of the polyphase motor;
correcting the current value of the rotating coordinate system using a table in which the angular frequency and the correction value are stored in association with each other;
motor control method. A motor control method according to claim 4,
The correction value corresponding to the measurement value is calculated by linear interpolation using the angular frequency stored in the table and the measurement value of the angular frequency, and the rotation coordinate system is calculated using the correction value. correct the current value,
motor control method. A motor control method according to any one of claims 1 to 5,
The correction value is
Defined as a plurality of parameters constituting a transformation on the rotating coordinate system that transforms the current value in the rotating coordinate system so as to cancel the phase delay amount of the phase current in the fixed coordinate system;
motor control method. A motor control method according to claim 6,
Based on each component of the phase delay amount in the fixed coordinate system, a phase angle change of the current value in the rotating coordinate system caused by the phase delay amount is obtained as a single parameter,
The correction value is defined as two parameters constituting a rotational transformation that shifts the phase of the current value in the rotating coordinate system in a direction that cancels out the phase angle change on the rotating coordinate system.
motor control method. A motor control device for vector-controlling the driving of a polyphase motor by feeding back current values obtained by coordinate-converting detected values of alternating current flowing in each phase of a polyphase motor from a fixed coordinate system to a rotating coordinate system. hand,
a power conversion unit that converts DC power into AC power and supplies the power to the multiphase motor;
a coordinate transformation unit that transforms the detected value into a current value in the rotating coordinate system by the coordinate transformation;
a correction unit that corrects the current value of the rotating coordinate system using a correction value preset based on the phase delay amount of the phase current of each phase of the multiphase motor;
a control unit that controls the power conversion unit based on the corrected current value of the rotating coordinate system and the output target value of the multiphase motor that is input from the outside;
motor controller.

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