Motor control device and motor control method

Abstract

To appropriately switch between voltage phase control and vector control while suppressing the occurrence of switching chattering.SOLUTION: A motor control device that switches between vector control and voltage phase control of a motor includes a switching unit that switches between the vector control and the voltage phase control depending on the driving state of the motor, and a first processing unit that performs filtering on a current used to calculate a switching initial value calculated when the switching unit switches between the voltage phase control and the vector control, and the first processing unit has a low-pass filter for calculating the initial value that removes sixth-order harmonic components of the fundamental frequency of the current.SELECTED DRAWING: Figure 2

Description

[Technical Field]

[0001] The present disclosure relates to a motor control device and a motor control method. [Background technology]

[0002] Conventionally, there is known a drive control device for an AC motor that switches between voltage phase control and vector control (see, for example, Patent Document 1). In this drive control device, a switching initial value is set as a control state variable for motor control after switching so that torque fluctuations do not occur before and after switching. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Application Laid-Open No. 2007-143235 Summary of the Invention [Problem to be solved by the invention]

[0004] In the drive control device of Patent Document 1, when switching from a state in which the motor is overmodulated by voltage phase control to vector control, the 6th-order harmonic components of the fundamental frequency of the phase current are superimposed on the d-axis and q-axis currents of the motor. In the drive control device of Patent Document 1, the initial switching value calculated based on the d-axis and q-axis currents fluctuates due to the 6th-order harmonic components. Here, a known motor control method is decoupling control using a decoupling term, which determines a voltage command value to compensate for the speed electromotive force generated inside the motor as the rotor rotates. Even in decoupling control, the decoupling term calculated based on the d-axis and q-axis currents fluctuates due to the 6th-order harmonic components. When at least one of the initial switching value and the decoupling term fluctuates, the voltage command value to the motor fluctuates, crossing the threshold for switching between voltage phase control and vector control, resulting in switching chatter.

[0005] Therefore, an object of the present disclosure is to provide a motor control device and a motor control method that can appropriately switch between voltage phase control and vector control while suppressing the occurrence of switching chattering. [Means for solving the problem]

[0006] The motor control device disclosed herein is a motor control device that switches between vector control and voltage phase control of a motor, and includes a switching unit that switches between the vector control and the voltage phase control depending on the driving state of the motor, and a first processing unit that performs filter processing on a current used to calculate a switching initial value calculated when the switching unit switches between the voltage phase control and the vector control, and the first processing unit has a low-pass filter for calculating the initial value that removes sixth-order harmonic components of the fundamental frequency of the current.

[0007] The motor control method disclosed herein is a motor control method executed by a motor control device that switches between vector control and voltage phase control of a motor, and the motor control device switches between the voltage phase control and the vector control depending on the driving state of the motor, and performs filtering on a current used to calculate an initial switching value calculated at the time of switching, and the filtering removes sixth-order harmonic components of the fundamental frequency of the current. [Effects of the Invention]

[0008] According to the present disclosure, it is possible to appropriately switch between voltage phase control and vector control while suppressing the occurrence of switching chattering. [Brief explanation of the drawings]

[0009] [Figure 1] FIG. 1 is a diagram relating to a motor control device according to a first embodiment. [Figure 2] FIG. 2 is a diagram showing a part of the motor control device according to the first embodiment. [Figure 3] FIG. 3 is a diagram showing a part of a motor control device according to the second embodiment. DETAILED DESCRIPTION OF THE INVENTION

[0010] Hereinafter, embodiments of the present disclosure will be described in detail with reference to the drawings. However, this disclosure is not limited to these embodiments. Furthermore, the components in the following embodiments include those that are easily replaceable by those skilled in the art, or those that are substantially identical. Furthermore, the components described below can be combined as appropriate, and when there are multiple embodiments, the respective embodiments can also be combined.

[0011] [First embodiment] A motor control device 10 according to the first embodiment is a device that controls the rotation of a motor 5, and switches between vector control and voltage phase control of the motor 5, and also performs decoupling control. The motor control device 10 is provided in a system 1 that includes the motor 5.

[0012] Fig. 1 is a diagram relating to a motor control device according to a first embodiment. Fig. 2 is a diagram relating to a part of the motor control device according to the first embodiment. First, a system 1 including a motor control device 10 will be described with reference to Fig. 1.

[0013] (system) The system 1 includes a motor 5, an inverter 6, and a motor control device 10.

[0014] The motor 5 is an AC motor, such as a three-phase motor, that rotates in response to an AC voltage supplied from an inverter 6. The motor control device 10 controls the motor 5 by converting a two-phase voltage of the d-axis and q-axis into a three-phase voltage of U-phase, V-phase, and W-phase. The motor 5 is provided with a position sensor 8 that detects the rotational position (magnetic pole position) θFB of the rotor provided inside.

[0015] The inverter 6 generates an AC voltage for driving the motor 5 and outputs the generated AC voltage to the motor 5. A current sensor 9 is provided between the inverter 6 and the motor 5 to detect a current IuvwFB in the UVW three phases flowing toward the motor 5.

[0016] The motor control device 10 controls the voltages Vuvw in the UVW three phases to control the motor 5 based on the required speed command. * Generate the generated voltage Vuvw * The PWM converter 7 generates a PWM signal that is a signal for controlling the inverter 6, and outputs the generated PWM signal to the inverter 6.

[0017] In this way, in the above-described system 1, the motor control device 10 generates a three-phase voltage based on a required speed command, the PWM converter 7 generates a PWM signal based on the three-phase voltage, and the inverter 6 outputs an AC voltage based on the PWM signal to the motor 5. In this way, the system 1 drives the motor 5 to rotate based on the required speed command. Next, the motor control device 10 will be described with reference to FIG. 1.

[0018] (Motor control device) As shown in FIG. 1, the motor control device 10 includes, in addition to the PWM converter 7, a vector control unit 21, a voltage phase control unit 22, a control switching determination unit 23, a control switching switch 24, a two-phase / three-phase conversion unit 25, a three-phase / two-phase conversion unit 26, and a differentiator 27.

[0019] The vector control unit 21 includes a speed control unit 31, a torque control unit 32, a current control unit 33, a first initial value calculation unit 34, and a second initial value calculation unit 35.

[0020] The speed control unit 31 outputs a speed command value ω *and the actual rotation speed ωFB of the rotating motor 5. The actual rotation speed of the motor 5 is input from a differentiator 27, which will be described later. The speed control unit 31 calculates the speed command value ωFB by dividing the input actual rotation speed ωFB by the speed command value ω * The torque command value T of the rotational torque of the motor 5 is set to * Output.

[0021] The torque control unit 32 receives the torque command value T * The torque control unit 32 receives the input torque command value T * Based on this, the current command value Idq to be applied to the motor 5 is * Output.

[0022] The current control unit 33 controls the current input to the motor 5, and receives the current command value Idq from the torque control unit 32. * is input. Current command value Idq * are the current command values ​​for the d-axis and q-axis. The current control unit 33 calculates the input current command values ​​Idq * Based on this, the voltage command value Vdq is input to the two-phase / three-phase conversion unit 25 described later. * Furthermore, the current control unit 33 executes decoupling control based on the current IdqFB output from the three-phase / two-phase conversion unit 26, which will be described later. The decoupling control compensates for interference caused by the speed electromotive force generated inside the motor 5, and suppresses current oscillation caused by interference between the d and q axes.

[0023] When switching from voltage phase control to vector control, the first initial value calculation unit 34 calculates a switching initial value of an integrator of a control state variable to be given to the speed control unit 31. The calculation process of the switching initial value by the first initial value calculation unit 34 is performed only once every time switching from voltage phase control to vector control. The first initial value calculation unit 34 outputs the calculated switching initial value to the speed control unit 31.

[0024] The second initial value calculation unit 35 calculates a switching initial value of an integrator of a control state variable to be given to the current control unit 33 when switching from voltage phase control to vector control. Similar to the first initial value calculation unit 34, the calculation process of the switching initial value by the second initial value calculation unit 35 is a process that is performed only once each time switching from voltage phase control to vector control. The second initial value calculation unit 35 outputs the calculated switching initial value to the current control unit 33. Details of the second initial value calculation unit 35 will be described later.

[0025] The voltage phase control unit 22 includes a phase control unit 41, a voltage control unit 42, and a third initial value calculation unit 43.

[0026] The phase control unit 41 determines a speed command value ω that is a command value for the required rotation speed of the motor 5. * and the actual rotation speed ωFB of the rotating motor 5. The actual rotation speed of the motor 5 is input from a differentiator 27, which will be described later. The phase control unit 41 calculates the speed command value ωFB by dividing the input actual rotation speed ωFB by the speed command value ω * The phase command value φ of the voltage applied to the motor 5 is set to * Output.

[0027] The voltage control unit 42 receives the voltage phase command value φ * The voltage control unit 42 receives the input phase command value φ * Based on this, the voltage command value Vdq is input to the two-phase / three-phase conversion unit 25 described later. * Output.

[0028] The control switching determination unit 23 performs control to determine switching between vector control and voltage phase control based on the driving state of the motor 5. The control switching determination unit 23 determines, for example, whether to execute vector control or voltage phase control based on the driving state of the motor 5, and outputs a determination flag as the determination result to the first initial value calculation unit 34, the second initial value calculation unit 35, and the control changeover switch 24.

[0029] The control changeover switch 24 changes the voltage command value Vdq from the vector control unit 21 based on the determination result of the control changeover determination unit 23. * and the voltage command value Vdq from the voltage phase control unit 22 * The voltage command value Vdq * is the voltage command value Vd that indicates the voltage of the d axis * and the voltage command value Vq that indicates the voltage of the q axis * Includes:

[0030] The two-phase / three-phase converter 25 converts the d-axis and q-axis voltage command values ​​Vdq * , that is, the voltage on the dq axis is the voltage Vuvw in the UVW three phases * and outputs it to the PWM converter 7. The rotational position θFB of the rotor of the motor 5 is input to the two-phase / three-phase conversion unit 25 from the position sensor 8, and conversion processing is performed based on the rotational position θFB.

[0031] The three-phase / two-phase conversion unit 26 converts the current IuvwFB in the UVW three-phases detected by the current sensor 9 into a current IdqFB in the dq axes, and outputs it to the current control unit 33 of the vector control unit 21. The rotational position θFB of the rotor of the motor 5 is input to the three-phase / two-phase conversion unit 26 from the position sensor 8, and conversion processing is performed based on the rotational position θFB.

[0032] The differentiator 27 acquires the rotor rotational position θFB output from the position sensor 8, and generates a speed (number of rotations) ωFB by differentiating the acquired rotational position θFB. This speed ωFB is expressed in mechanical angles. The differentiator 27 outputs the generated speed ωFB to the speed control unit 31 of the vector control unit 21 and the phase control unit 41 of the voltage phase control unit 22.

[0033] In the above motor control device 10, the control switching determination unit 23 determines whether to switch between vector control and voltage phase control based on the driving state of the motor 5, and based on the determination result, the vector control unit 21 or the voltage phase control unit 22 controls the driving of the motor 5.

[0034] Next, the current control unit 33 and the second initial value calculation unit 35 of the vector control unit 21 will be described with reference to Fig. 2. Note that, although the current control unit 33 and the second initial value calculation unit 35 for the d axis will be described in Fig. 2, the same applies to the q axis, and therefore the description of the q axis and the symbol "q" will be omitted.

[0035] 2, the current control unit 33 includes a subtractor 51, a P controller 52, an I controller 53, a first adder 54, a non-interference term processing unit 55, and a second adder 56. The non-interference term processing unit 55 includes a low-pass filter (third low-pass filter) 57, a first calculation unit 58, a second calculation unit 59, and a multiplier 60.

[0036] The subtractor 51 subtracts the d-axis current command value Id * The d-axis current deviation Δid is calculated by subtracting the current IdFB from the P controller 52. The P controller 52 performs proportional control by multiplying the d-axis current deviation Δid calculated by the subtractor 51 by a proportional gain. The I controller 53 performs integral control by multiplying the d-axis current deviation Δid calculated by the subtractor 51 by an integral gain and integrating the result. The first adder 54 adds the output value of the P controller 52 and the output value of the I controller 53 and outputs the addition result to the second adder 56.

[0037] In the non-interference term processing unit 55, the low-pass filter 57 functions as a second processing unit that performs filtering on the current IdFB input to the current control unit 33. The low-pass filter 57 is a filter that removes the sixth-order harmonic components of the fundamental frequency of the current IdFB. The low-pass filter 57 may have a cutoff frequency that removes the sixth-order harmonic components, for example, a cutoff frequency that is 6f or less relative to the fundamental frequency f. Note that the cutoff frequency of the low-pass filter 57 may be variable depending on the fundamental frequency of the current of the motor 5.

[0038] A first calculation unit 58 calculates a q-axis inductance Lq based on the current IdFB filtered by the low-pass filter 57. A second calculation unit 59 calculates an actual rotation speed (electrical angle) ωe based on the speed ωFB input to the vector control unit 21. The actual rotation speed ωe is equal to ωFB × p, where p is the number of pole pairs. A multiplier 60 multiplies the q-axis inductance Lq calculated by the first calculation unit 58, the actual rotation speed ωe calculated by the second calculation unit 59, and the q-axis current Iq together, and outputs the multiplication result (-Lq·ωe·Iq) to the second adder 56.

[0039] The second adder 56 adds the addition result output from the first adder 54 and the multiplication result output from the multiplier 60, and outputs the addition result as a d-axis voltage command value Vd * Output.

[0040] Next, a description will be given of the second initial value calculation unit 35. The second initial value calculation unit 35 includes a d-axis voltage command processing unit 71, a non-interference term processing unit 72, a proportional term processing unit 73, and a subtractor 74.

[0041] The d-axis voltage command processing unit 71 calculates the previous value, that is, the d-axis voltage command value Vd calculated during the voltage phase control one control cycle ago. * is obtained and output to the subtractor 74.

[0042] Similar to the non-interference term processing unit 55, the non-interference term processing unit 72 includes a low-pass filter (first low-pass filter) 77, a first calculation unit 78, a second calculation unit 79, and a multiplier .

[0043] In the non-interference term processing unit 72, the low-pass filter 77 functions as a first processing unit that performs filtering on the previous value, that is, the current IdFB calculated during voltage phase control one control cycle ago. Similar to the low-pass filter 57, the low-pass filter 77 is a filter that removes the sixth-order harmonic components of the fundamental frequency of the current IdFB. The low-pass filter 77 may have any cutoff frequency that removes the sixth-order harmonic components, for example, a cutoff frequency that is 6f or less relative to the fundamental frequency f.

[0044] A first calculation unit 78 calculates a q-axis inductance Lq based on the current IdFB filtered by the low-pass filter 77. A second calculation unit 79 calculates an actual rotation speed (electrical angle) ωe based on the previous value, that is, the speed ωFB calculated during voltage phase control one control cycle ago. A multiplier 80 multiplies the q-axis inductance Lq calculated by the first calculation unit 78, the actual rotation speed ωe calculated by the second calculation unit 79, and the previous value of the q-axis current Iq, and outputs the multiplication result (−Lq·ωe·Iq) to the subtractor 74.

[0045] The proportional term processing unit 73 includes a torque command processing unit 85, a torque / current processing unit 86, a low-pass filter 87, an id command processing unit 88, a subtractor 89, an actual current processing unit 90, a low-pass filter (second low-pass filter) 91, and an operator 92.

[0046] The torque command processing unit 85 calculates the previous torque command value T * Specifically, the previous torque command value T is calculated from a predetermined relational expression based on the current value of the motor 5. * The torque / current processing unit 86 calculates the torque command value T * Then, using a predetermined conversion table, the current amplitude command I * est and phase command β * est The low-pass filter 87 obtains the current amplitude command I * est and phase command β * estThe id command processing unit 88 performs filtering on the current amplitude command I * est and phase command β * est The d-axis current command value is estimated from the input signal and output to the subtractor 89.

[0047] The actual current processing unit 90 acquires the previous actual d-axis current Id. The low-pass filter 91 functions as a first processing unit that performs filtering on the acquired d-axis current Id. Like the low-pass filters 57 and 77, the low-pass filter 91 is a filter that removes sixth-order harmonic components of the fundamental frequency of the d-axis current Id. The low-pass filter 91 may have any cutoff frequency that removes sixth-order harmonic components, for example, a cutoff frequency that is 6f or less relative to the fundamental frequency f. Note that, like the low-pass filter 57, the cutoff frequency of the low-pass filters 77 and 91 may also be variable depending on the fundamental frequency of the current of the motor 5. In this way, the low-pass filters 77 and 91 are used as low-pass filters for initial value calculation and function as a first processing unit that performs filtering on the current used to calculate the switching initial value.

[0048] The subtractor 89 subtracts the d-axis current command value Id output from the id command processing unit 88. * The calculator 92 subtracts the actual d-axis current Id filtered by the low-pass filter 91 from the subtractor 74. The calculator 92 multiplies the subtraction result output from the subtractor 89 by the proportional gain Kp and outputs the multiplication result (Kp_id) to the subtractor 74.

[0049] The subtractor 74 subtracts the d-axis voltage command value Vd * The subtractor 74 subtracts the multiplication result (-Lq·ωe·Iq) output from the non-interference term processing unit 72 and the multiplication result (Kp_id) output from the proportional term processing unit 73 from the current I controller 53 of the current control unit 33. The subtractor 74 then outputs the subtraction result as the switching initial value to the I controller 53 of the current control unit 33.

[0050] (Motor control method) Next, a motor control method by the motor control device 10 will be described. In the motor control device 10, the current control unit 33 and the second initial value calculation unit 35 are provided with a low-pass filter (second low-pass filter) 91, a low-pass filter (first low-pass filter) 77, and a low-pass filter (third low-pass filter) 57. Therefore, when switching from voltage phase control to vector control, the motor control device 10 removes sixth-order harmonic components contained in the d-axis current Id and the q-axis current Iq at the initial value for switching using the low-pass filter 77 and the low-pass filter 91. Furthermore, when switching from voltage phase control to vector control, the motor control device 10 removes sixth-order harmonic components contained in the d-axis current Id and the q-axis current Iq in the decoupling term related to the decoupling control of the motor 5 using the low-pass filter 57. As a result, the motor control device 10 can obtain a voltage command value Vdq * The motor control device 10 can suppress fluctuations in the voltage command value Vdq across the voltage threshold value at which the voltage phase control and the vector control are switched. * This suppresses fluctuations in the switching frequency and suppresses the occurrence of switching chattering.

[0051] It is preferable that the low-pass filter (second low-pass filter) 91, the low-pass filter (first low-pass filter) 77, and the low-pass filter (third low-pass filter) 57 have the same cutoff frequency.

[0052] The cutoff frequency of the low-pass filters 57 , 77 , and 91 may be the same as the control frequency of the current in the current control section 33 .

[0053] In addition, in the first embodiment, the detected q-axis current IqFB is filtered by the non-interference term low-pass filters 57, 77, but the low-pass filters 57, 77 may be placed on the output side of the first calculation units 58, 78 or the multipliers 60, 80.

[0054] Furthermore, the second initial value calculation unit 35 of the first embodiment may be applied to the first initial value calculation unit 34 and the third initial value calculation unit 43. In other words, the first initial value calculation unit 34 and the third initial value calculation unit 43 may have a proportional term processing unit 73 similar to that of the second initial value calculation unit 35. In this case, the motor control device 10 can remove the sixth-order harmonic components contained in the d-axis current Id and the q-axis current Iq not only when switching from voltage phase control to vector control, but also when switching from vector control to voltage phase control.

[0055] [Second embodiment] Next, a second embodiment will be described with reference to Fig. 3. Fig. 3 is a diagram showing a part of a motor control device according to the second embodiment. In the second embodiment, to avoid redundant description, only parts that differ from the first embodiment will be described, and parts that have the same configuration as the first embodiment will be denoted by the same reference numerals.

[0056] (Motor control device) The motor control device 100 of the second embodiment selects whether or not to perform filtering by the low-pass filter 57 depending on the modulation factor, which is the ratio of the amplitude of the fundamental wave component of the phase voltage to Vdc / 2. Specifically, the motor control device 100 of the second embodiment further includes a determination unit 101 in addition to the components of the motor control device 10 of the first embodiment.

[0057] The judging unit 101 receives the filtered q-axis current IqFB (and the d-axis current IdFB) as "input 1" and the unfiltered q-axis current IqFB (and the d-axis current IdFB) as "input 2". The judging unit 101 judges whether the modulation factor of the motor, which is the previous value, is equal to or exceeds a predetermined modulation factor (m s ), the q-axis current IqFB (and the d-axis current IdFB) of the input 1 that has been subjected to the filtering process is output to the first calculation unit 58. On the other hand, the determination unit 101 determines whether the modulation factor of the motor that is the previous value is equal to or greater than a predetermined modulation factor (m s), the q-axis current IqFB (and the d-axis current IdFB) of input 2 that has not been subjected to filtering is output to the first calculation unit 58. Here, a predetermined modulation factor (m s ) is determined based on the modulation factor of overmodulation corresponding to the magnitude of the sixth-order harmonic component of the fundamental frequency of the dq-axis current, and is determined based on the modulation factor of overmodulation where the harmonic component is particularly prominent.

[0058] As described above, the motor control devices 10 and 100 according to the first and second embodiments can be understood, for example, as follows.

[0059] The motor control device 10, 100 according to the first aspect is a motor control device 10, 100 that switches between vector control and voltage phase control of the motor 5, and includes a switching unit (control switching switch 24) that switches between the vector control and the voltage phase control depending on the driving state of the motor 5, and a first processing unit that performs filtering on a current used to calculate a switching initial value calculated when the switching unit switches between the voltage phase control and the vector control, and the first processing unit has a low-pass filter 77, 91 for calculating the initial value that removes sixth-order harmonic components of the fundamental frequency of the current.

[0060] According to this configuration, when switching between voltage phase control and vector control, the low-pass filters 77 and 91 for calculating the initial value can remove the sixth-order harmonic components of the fundamental frequency of the current from the current used to calculate the initial value for switching. * Since fluctuations in the switching threshold can be suppressed, the occurrence of switching chattering across the switching threshold can be suppressed.

[0061] In a second aspect, the motor control devices 10, 100 according to the first aspect further perform non-interference control to compensate for interference due to speed electromotive force generated inside the motor, and the low-pass filter for calculating the initial value has a first low-pass filter that performs filtering on the current used to calculate the non-interference term related to the switching initial value in the non-interference control of the motor.

[0062] According to this configuration, by using the first low-pass filter 77 as a low-pass filter for calculating the initial value, it is possible to remove the sixth-order harmonic component of the fundamental frequency of the current from the current used to calculate the decoupling term when switching between voltage phase control and vector control. * Since fluctuations in the switching threshold can be effectively suppressed, it is possible to suppress the occurrence of switching chattering across the switching threshold.

[0063] As a third aspect, in the motor control device 10, 100 according to the first or second aspect, the low-pass filter for calculating the initial value has a second low-pass filter that performs filtering on the current used to calculate the proportional term related to the switching initial value.

[0064] According to this configuration, by using the second low-pass filter 91 as a low-pass filter for calculating the initial value, it is possible to remove the sixth-order harmonic component of the fundamental frequency of the current from the current used to calculate the proportional term when switching between voltage phase control and vector control. * Since fluctuations in the switching threshold can be suppressed, switching chattering can be suppressed from occurring when the switching threshold is crossed.

[0065] As a fourth aspect, in the motor control device 10, 100 according to any one of the first to third aspects, a decoupling control is further performed to compensate for interference due to speed electromotive force generated inside the motor, and a second processing unit is further provided that performs filtering on the current used to calculate the decoupling term related to the decoupling control of the motor, and the second processing unit has a third low-pass filter 57 that removes the sixth-order harmonic component of the fundamental frequency of the current.

[0066] According to this configuration, when switching between voltage phase control and vector control, the third low-pass filter 57 can also remove the sixth-order harmonic component of the fundamental frequency of the current used to calculate the decoupling term related to the decoupling control of the motor. * Since fluctuations in the switching threshold can be further suppressed, it is possible to suppress the occurrence of switching chattering across the switching threshold.

[0067] As a fifth aspect, in the motor control device 10, 100 relating to the fourth aspect, the low-pass filter 77, 91 for calculating the initial value of the first processing unit and the third low-pass filter 57 of the second processing unit are low-pass filters with the same cutoff frequency.

[0068] According to this configuration, the low-pass filters 57, 77, and 91 can have the same cutoff frequency, so that the responsiveness of the current after filtering can be matched, and the influence of different current responsiveness can be suppressed.

[0069] As a sixth aspect, in the motor control device 100 according to the fourth or fifth aspect, the third low-pass filter 57 performs filtering when the motor 5 is in an overmodulation driving state, but does not perform filtering when the motor 5 is not in an overmodulation driving state.

[0070] According to this configuration, the filter process is not executed when the motor 5 is not in the overmodulation drive state, so that the deterioration of responsiveness caused by the execution of the filter process can be suppressed.

[0071] As a seventh aspect, in the motor control device 100 according to the fourth or fifth aspect, the third low-pass filter 57 performs filtering when the modulation rate is equal to or greater than a threshold value determined based on the modulation rate of overmodulation corresponding to the magnitude of the sixth-order harmonic component of the fundamental frequency of the current, but does not perform filtering when the modulation rate is less than the threshold value.

[0072] According to this configuration, the motor 5 does not perform filtering when it is not affected by the sixth harmonic component of the fundamental frequency of the current (when the harmonic component is not significant), thereby suppressing deterioration in responsiveness due to the execution of filtering.

[0073] As an eighth aspect, in the motor control device 10, 100 relating to any one of the second to fifth aspects, the low-pass filter 77, 91 for calculating the initial value of the first processing unit and the third low-pass filter 57 of the second processing unit have cutoff frequencies that are the same as the control frequency of the current.

[0074] According to this configuration, the responsiveness of the current after filtering can be matched with the responsiveness of the current control, so that the influence of switching between the execution and non-execution of filtering can be suppressed.

[0075] A motor control method according to a ninth aspect is a motor control method executed by a motor control device 10, 100 that switches between vector control and voltage phase control of a motor 5 and also executes non-interference control that compensates for interference due to speed electromotive force generated inside the motor, wherein the motor control device 10, 100 switches between the voltage phase control and the vector control depending on the driving state of the motor 5, and performs filtering on the current used to calculate the initial value for switching that is calculated at the time of switching, and the filtering removes sixth-order harmonic components of the fundamental frequency of the current.

[0076] According to this configuration, when switching between voltage phase control and vector control, filtering is performed on the current used to calculate the initial value for switching, thereby making it possible to remove the sixth-order harmonic component of the fundamental frequency of the current. * Since fluctuations in the switching threshold can be suppressed, the occurrence of switching chattering across the switching threshold can be suppressed. [Explanation of symbols]

[0077] 1 System 5 motors 6 inverters 7 PWM converter 8 Position Sensor 9 Current Sensor 10, 100 Motor control device 21 Vector control unit 22 Voltage phase control section 23 Control switching determination unit 24 Control switch 25 Two-phase / three-phase conversion unit 26 Three-phase / two-phase conversion unit 31 Speed ​​control section 32 Torque control section 33 Current control section 34 First initial value calculation unit 35 Second initial value calculation unit 41 Phase control section 42 Voltage control section 43 Third initial value calculation unit 55 Non-interference term processing section 57 Low-pass filter (third low-pass filter) 72 Non-interference term processing section 73 Proportional term processing section 77 Low-pass filter (first low-pass filter) 91 Low-pass filter (second low-pass filter) 101 Judgment section

Claims

1. A motor control device that switches between vector control and voltage phase control of a motor, a switching unit that switches between the vector control and the voltage phase control in accordance with a driving state of the motor; a first processing unit that performs a filter process on a current used to calculate a switching initial value that is calculated when the switching unit switches between the voltage phase control and the vector control; The motor control device wherein the first processing unit has a low-pass filter for calculating an initial value that removes a sixth-order harmonic component of the fundamental frequency of the current.

2. a decoupling control for compensating for interference caused by a speed electromotive force generated inside the motor is further performed; The low-pass filter for calculating the initial value is 2. The motor control device according to claim 1, further comprising a first low-pass filter that performs filtering on a current used to calculate a decoupling term related to the initial value for switching in the decoupling control of the motor.

3. The low-pass filter for calculating the initial value is 2. The motor control device according to claim 1, further comprising a second low-pass filter that performs filtering on the current used to calculate the proportional term related to the initial value for switching.

4. a decoupling control for compensating for interference caused by a speed electromotive force generated inside the motor is further performed; a second processing unit that performs filtering on a current used to calculate a decoupling term related to the decoupling control of the motor; 2. The motor control device according to claim 1, wherein the second processing unit has a third low-pass filter that removes a sixth-order harmonic component of the fundamental frequency of the current.

5. 5. The motor control device according to claim 4, wherein the low-pass filter for calculating the initial value in the first processing unit and the third low-pass filter in the second processing unit are low-pass filters with the same cutoff frequency.

6. 5. The motor control device according to claim 4, wherein the third low-pass filter performs filtering when the motor is in an overmodulation driving state, but does not perform filtering when the motor is not in an overmodulation driving state.

7. 5. The motor control device according to claim 4, wherein the third low-pass filter performs filtering when the modulation rate is equal to or greater than a threshold value of the modulation rate determined based on a modulation rate of overmodulation corresponding to the magnitude of a sixth-order harmonic component of the fundamental frequency of the current, but does not perform filtering when the modulation rate is smaller than the threshold value.

8. 5. The motor control device according to claim 4, wherein the low-pass filter for calculating the initial value of the first processing unit and the third low-pass filter of the second processing unit have cutoff frequencies that are the same as the control frequency of the current.

9. A motor control method executed by a motor control device that switches between vector control and voltage phase control of a motor and also executes decoupling control that compensates for interference caused by speed electromotive force generated inside the motor, comprising: The motor control device includes: switching between the voltage phase control and the vector control according to a driving state of the motor; Filtering is performed on the current used to calculate the initial switching value that is calculated when switching. The motor control method includes filtering to remove sixth-order harmonic components of the fundamental frequency of the current.

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