Motor control device

Abstract

To stabilize the control of a motor.SOLUTION: In a motor control device 100a, adders 44 and 45 add a high-frequency removal d-axis driving voltage command value Vdm* and a high-frequency removal q-axis driving voltage command value Vqm*, which are obtained by removing a high frequency component from a d-axis driving voltage command value Vdm and a q-axis driving voltage command value Vqm for driving a motor M at a desired rotation number, to a d-axis high-frequency voltage command value Vdh* and a q-axis high-frequency voltage command value Vqh* for generating a high-frequency current to be used for estimation of a rotor position of the motor M to calculate a d-axis voltage command value Vd* and a q-axis voltage command value Vq*. An axial error calculation unit 30 calculates an axial error Δθ by using the high-frequency current generated in response to the application of the d-axis high-frequency voltage command value Vdh* and the q-axis high-frequency voltage command value Vqh*. A drive component removal filter 50a removes a current component generated by the drive of the motor M from a d-axis current Id and a q-axis current Iq.SELECTED DRAWING: Figure 1

Description

Technical Field

[0001] The present disclosure relates to a motor control device.

Background Art

[0002] As one of the rotor position estimation techniques in sensorless vector control for an AC motor, there is a technique of applying a high-frequency voltage that does not contribute to torque generation to the motor and estimating the rotor position using the high-frequency component (hereinafter sometimes referred to as "high-frequency current") included in the detected current. In this technique, the rotor position is estimated based on the in-phase current vector that rotates in the same direction as the high-frequency magnetic flux vector generated in response to the application of the high-frequency voltage and the mirror-image current vector that rotates in the opposite direction to the high-frequency magnetic flux vector (Patent Document 1). Hereinafter, the in-phase current vector and the mirror-image current vector may be collectively referred to as the "in-phase mirror-image current vector".

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] Here, if the pass frequency band in the filter used when generating the in-phase mirror-image current vector is not appropriately set, the accuracy of rotor position estimation (hereinafter sometimes referred to as "position estimation accuracy") decreases due to the response delay of the filter or the extraction of current components other than the high-frequency current. Also, when the frequency of the current component for driving the motor and the frequency of the high-frequency current for rotor position estimation are set close to each other, or when the command value of the high-frequency voltage is not correctly generated due to the influence of the high-frequency current component caused by the cogging torque of the motor, the position estimation accuracy also decreases. As a result, the control of the motor becomes unstable.

[0005] Therefore, the present disclosure proposes a technique capable of stabilizing the control of a motor.

Means for Solving the Problems

[0006] The motor control device of the present disclosure includes a calculator, an axis error calculator, a current calculator, a converter, and a drive component removal filter. The calculator calculates a voltage command value based on a drive voltage command value for driving the motor at a desired rotation speed and a high-frequency voltage command value for generating a high-frequency current used for estimating the rotor position of the motor. The axis error calculator calculates an axis error using the high-frequency current generated in response to the application of the high-frequency voltage command value. The current calculator calculates a three-phase current including the high-frequency current. The converter converts the three-phase current into a two-phase current including the high-frequency current. The drive component removal filter extracts the high-frequency current from the two-phase current by removing a current component generated accompanying the driving of the motor from the two-phase current.

Advantages of the Invention

[0007] According to the present disclosure, it is possible to stabilize the control of a motor.

Brief Description of the Drawings

[0008]

Figure 1

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DETAILED DESCRIPTION OF THE INVENTION

[0009] Hereinafter, embodiments of the present disclosure will be described with reference to the drawings. In the following embodiments, the same parts may be denoted by the same reference numerals, and redundant descriptions may be omitted.

[0010] In the present disclosure, a motor control device that performs sensorless vector control of a permanent magnet synchronous motor (PMSM) that drives a compressor will be described as an example. However, the disclosed technology is widely applicable to a motor control device that estimates the rotor position using magnetic pole polarities for a motor having magnetic pole polarities.

[0011] [Embodiment 1] <Configuration of Motor Control Device> FIG. 1 is a diagram showing a configuration example of a motor control device according to Embodiment 1 of the present disclosure. In FIG. 1, a motor control device 100a includes subtracters 11, 18, 19, a speed controller 12, adders 21, 22, 44, 45, a current command value calculator 14, a current controller 20, a d-q / u, v, w converter 23, a PWM (Pulse Width Modulation) modulator 24, and an IPM (Intelligent Power Module) 25. The IPM 25 is connected to a motor M. An example of the motor M is a PMSM.

[0012] Further, the motor control device 100a includes a shunt resistor 26, current sensors 27a, 27b, and a three-phase current calculator 28. Note that the motor control device 100a may have either the shunt resistor 26 or the current sensors 27a, 27b.

[0013] Further, the motor control device 100a includes a u, v, w / d-q converter 29, an axis error calculator 30, a PLL (Phase Locked Loop) controller 31, a position estimator 32, a 1 / Pn processor 33, and a decoupling controller 36.

[0014] Further, the motor control device 100a includes high-pass filters 41, 42, a high-frequency voltage command value generator 43, a Pn processor 46, high-frequency voltage removal filters 61, 62, and a drive component removal filter 50a.

[0015] The subtracter 11 calculates an angular velocity error Δω by subtracting the mechanical angular velocity estimation value ωm, which is the current estimated angular velocity output from the 1 / Pn processor 33, from the mechanical angular velocity command value ωm input from outside the motor control device 100a (for example, a higher-level controller) to the motor control device 100a. Here, the mechanical angular velocity command value ωm * is a command value determined based on the desired rotational speed of the motor M. * The speed controller 12 generates a torque command value T

[0016] such that the average of the angular velocity error Δω approaches 0. * ​

[0017] The current command value calculator 14 distributes the torque command value T * to the d-axis current command value Id * and the q-axis current command value Iq * on the d-q coordinate axes.

[0018] The subtractor 18 subtracts the high-frequency removed d-axis current Idm output from the high-frequency removal filter 41 from the d-axis current command value Id * to calculate the d-axis current error Id_diff, which is the error between the d-axis current command value Id * and the high-frequency removed d-axis current Idm. The subtractor 19 subtracts the high-frequency removed q-axis current Iqm output from the high-frequency removal filter 42 from the q-axis current command value Iq * to calculate the q-axis current error Iq_diff, which is the error between the q-axis current command value Iq * and the high-frequency removed q-axis current Iqm.

[0019] The current controller 20 calculates a temporary d-axis voltage command value Vdt by performing PI (Proportional Integral) control based on the input d-axis current error Id_diff. Also, the current controller 20 calculates a temporary q-axis voltage command value Vqt by performing PI control based on the input q-axis current error Iq_diff.

[0020] The decoupling controller 36 generates a d-axis decoupling voltage command value Vda for compensating the temporary d-axis voltage command value Vdt based on the electrical angular velocity command value ωe * output from the Pn processor 46 and the d-axis current command value Id * output from the current command value calculator 14. Also, the decoupling controller 36 generates a d-axis decoupling voltage command value Vda for compensating the temporary d-axis voltage command value Vdt based on the electrical angular velocity command value ωe * output from the Pn processor 46 and the q-axis current command value Iq *Based on this, a q-axis decoupled voltage command value Vqa for compensating the virtual q-axis voltage command value Vqt is generated. The d-axis decoupled voltage command value Vda and the q-axis decoupled voltage command value Vqa are decoupled compensation values for canceling the interference between the d-q coordinate axes by feedforward.

[0021] The adder 21 calculates the d-axis drive voltage command value Vdm by adding the d-axis decoupled voltage command value Vda to the virtual d-axis voltage command value Vdt. The adder 22 calculates the q-axis drive voltage command value Vqm by adding the q-axis decoupled voltage command value Vqa to the virtual q-axis voltage command value Vqt. Thereby, the d-axis drive voltage command value Vdm and the q-axis drive voltage command value Vqm in which the interference between the d-q coordinate axes is canceled by feedforward are obtained.

[0022] The high-frequency voltage removal filter 61 extracts the high-frequency removal d-axis drive voltage command value Vdm from the d-axis drive voltage command value Vdm by removing the high-frequency components existing in the high-frequency current frequency fh * (fh * = ωh * / 2π) band of the d-axis drive voltage command value Vdm. Also, the high-frequency voltage removal filter 62 extracts the high-frequency removal q-axis drive voltage command value Vqm from the q-axis drive voltage command value Vqm by removing the high-frequency components existing in the high-frequency current frequency fh * band of the q-axis drive voltage command value Vqm. The high-frequency voltage removal filters 61 and 62 are realized by, for example, a band-stop filter F(s). The high-frequency voltage angular frequency (hereinafter sometimes referred to as "high-frequency angular frequency") ωh * is input from the outside of the motor control device 100a (for example, a higher controller) to the motor control device 100a. In Equation (1), "s" is a Laplace operator, "d" is the notch depth, and "ζ" is a predetermined filter coefficient representing the notch bandwidth. * The band-stop filter F(s) having the high-frequency angular frequency ωh * as the center frequency of the band-stop can be realized according to Equation (1). The high-frequency angular frequency ωh * is input from the outside of the motor control device 100a (for example, a higher controller) to the motor control device 100a. In Equation (1), "s" is a Laplace operator, "d" is the notch depth, and "ζ" is a predetermined filter coefficient representing the notch bandwidth.

Number

[0023] The d-q / u,v,w converter 23 converts the two-phase d-axis voltage command value Vd * and the q-axis voltage command value Vq * output from the adders 44 and 45 into the three-phase U-phase output voltage command value Vu * , V-phase output voltage command value Vv * and W-phase output voltage command value Vw * based on the electrical angular phase θe output from the position estimator 32. The electrical angular phase θe output from the position estimator 32 indicates the current rotor position of the motor M.

[0024] The PWM modulator 24 generates six-phase PWM signals based on the U-phase output voltage command value Vu * , V-phase output voltage command value Vv * , W-phase output voltage command value Vw * and a PWM carrier signal, and outputs the generated six-phase PWM signals to the IPM 25.

[0025] Based on the six-phase PWM signals output from the PWM modulator 24, the IPM 25 generates three-phase AC voltages of the U-phase, V-phase, and W-phase from the DC voltage Vdc, and applies the generated three-phase AC voltages to the U-phase, V-phase, and W-phase of the motor M.

[0026] When the bus current is detected by the one-shunt method using the shunt resistor 26, the three-phase current calculator 28 calculates the U-phase current Iu, V-phase current Iv, and W-phase current Iw of the motor M from the six-phase PWM switching information output from the PWM modulator 24 and the detected bus current. Alternatively, when the U-phase current and V-phase current are detected by the current sensors 27a and 27b, the three-phase current calculator 28 calculates the remaining W-phase current Iw based on Kirchhoff's law of "Iu + Iv + Iw = 0". The three-phase current calculator 28 outputs the phase currents Iu, Iv, and Iw of each phase to the u,v,w / d-q converter 29.

[0027] The u, v, w / d-q converter 29 converts the three-phase U-phase current Iu, V-phase current Iv, and W-phase current Iw into the two-phase d-axis current Id and q-axis current Iq based on the electrical angular phase θe output from the position estimator 32.

[0028] The high-frequency removal filter 41 extracts the high-frequency removal d-axis current Idm, which is a driving component contributing to torque generation, from the d-axis current Id by removing the high-frequency component of the d-axis current Id. Also, the high-frequency removal filter 42 extracts the high-frequency removal q-axis current Iqm, which is a driving component contributing to torque generation, from the q-axis current Iq by removing the high-frequency component of the q-axis current Iq. The high-frequency removal filters 41 and 42 are realized, for example, by a band-stop filter F(s). The high-frequency angular frequency ωh * The band-stop filter F(s) having the high-frequency angular frequency ωh as the center frequency of the band-stop can be realized according to Equation (1).

[0029] The PLL controller 31 calculates the electrical angular estimated angular velocity ωe, which is the current estimated angular velocity of the motor M, based on the axis error Δθ.

[0030] The position estimator 32 estimates the electrical angular phase θe based on the electrical angular estimated angular velocity ωe.

[0031] The 1 / Pn processor 33 calculates the mechanical angular estimated angular velocity ωm by dividing the electrical angular estimated angular velocity ωe by the number of pole pairs Pn of the motor M.

[0032] The Pn processor 46 * multiplies the mechanical angular velocity command value ωm * by the number of pole pairs Pn of the motor M to calculate the electrical angular velocity command value ωe.

[0033] The high-frequency voltage command value generator 43 generates the d-axis high-frequency voltage command value Vdh based on the high-frequency angular frequency ωh * and the high-frequency voltage amplitude command value Vh input from the outside of the motor control device 100a (for example, a higher-level controller) to the motor control device 100a. * * ​and the q-axis high-frequency voltage command value Vqh * are generated. Hereinafter, the d-axis high-frequency voltage command value and the q-axis high-frequency voltage command value may be collectively referred to as the "high-frequency voltage vector". The high-frequency voltage vector Vdh * , Vqh * is generated to generate a high-frequency current used for estimating the rotor position and does not contribute to torque generation for estimating the rotor position. That is, the high-frequency current used for estimating the rotor position is generated in response to the application of the high-frequency voltage vectors Vdh * , Vqh * to the motor M.

[0034] The adder 44 calculates the d-axis voltage command value Vd * by adding the high-frequency removal d-axis drive voltage command value Vdm * and the d-axis high-frequency voltage command value Vdh * . The adder 45 calculates the q-axis voltage command value Vq * by adding the high-frequency removal q-axis drive voltage command value Vqm * and the q-axis high-frequency voltage command value Vqh * . Hereinafter, the d-axis drive voltage command value Vdm and the q-axis drive voltage command value Vqm are collectively referred to as the "drive voltage command value Vm", and the high-frequency removal d-axis drive voltage command value Vdm * and the high-frequency removal q-axis drive voltage command value Vqm * may be collectively referred to as the "high-frequency removal drive voltage command value Vm * ".

[0035] The drive component removal filter 50a extracts the high-frequency d-axis current Idh from the d-axis current Id and the high-frequency q-axis current Iqh from the q-axis current Iq by removing components other than the high-frequency components in the frequency band of the high-frequency current frequency fh * based on the mechanical angular velocity command value ωm * and the high-frequency angular frequency ωh * . The non-high-frequency current is a current component generated along with the drive of the motor M. Hereinafter, the high-frequency d-axis current Idh and the high-frequency q-axis current Iqh may be collectively referred to as the "high-frequency current Ih".

[0036] The axis error calculator 30 calculates an axis error Δθ (the difference between the actual rotation axis and the estimated rotation axis) based on the high-frequency d-axis current Idh, the high-frequency q-axis current Iqh, and the high-frequency angular frequency ωh. That is, the axis error calculator 30 calculates the axis error Δθ, which is the deviation between the d-q coordinate axes and the estimated coordinate axes of the d-q coordinate axes, using the high-frequency current vector generated in response to the application of the high-frequency voltage vectors Vdh * , Vqh * . *

[0037] <Configuration of High-Frequency Voltage Command Value Generator> FIG. 2 is a diagram showing a configuration example of a high-frequency voltage command value generator according to Embodiment 1 of the present disclosure. In FIG. 2, the high-frequency voltage command value generator 43 includes a phase generator 43a, a cosine-sine signal generator 43b, and a multiplier 43c.

[0038] The phase generator 43a generates a high-frequency phase θh, which is the phase of the high-frequency voltage vector, by integrating the high-frequency angular frequency ωh in the range of “0 ≦ θh ≦ 2π”. *

[0039] The cosine-sine signal generator 43b generates cosine and sine values u(θh) of the high-frequency phase θh according to Equation (2).

Equation

[0040] The multiplier 43c generates a d-axis high-frequency voltage command value Vdh * and a q-axis high-frequency voltage command value Vqh * according to Equation (3) based on the cosine and sine values u(θh) and the high-frequency voltage amplitude command value Vh * .

Equation

[0041] <Configuration of Axis Error Calculator> ​​FIG. 3 is a diagram showing a configuration example of the shaft error calculator according to Embodiment 1 of the present disclosure. In FIG. 3, the shaft error calculator 30 includes a synchronous mirror image current vector generator 301 and a mirror image estimator 302. The shaft error calculator 30 utilizes the magnetic salient polarity of the motor M and calculates the shaft error Δθ based on the high-frequency angular frequency ωh * and the high-frequency d-axis current Idh and the high-frequency q-axis current Iqh. FIG. 4 is a diagram showing a configuration example of the synchronous mirror image current vector generator according to Embodiment 1 of the present disclosure. In FIG. 4, the synchronous mirror image current vector generator 301 includes an inverter b11 and D-factor filters b12, b13.

[0042] In FIG. 4, the inverter b11 inverts the sign of the high-frequency angular frequency ωh * and outputs the inverted high-frequency angular frequency -ωh * to the D-factor filter b12.

[0043] The D-factor filters b12, b13 are filters that separate and extract the in-phase component and the mirror image component. The D-factor in the D-factor filters b12, b13 is defined by Equation (4) using the identity matrix I, the alternating matrix J, and the Laplace operator s.

Equation

[0044] Based on the inverted high-frequency angular frequency -ωh * , the D-factor filter b12 detects the in-phase current vector Ihp included in the high-frequency d-axis current Idh and the high-frequency q-axis current Iqh. The in-phase current vector Ihp rotates in the same direction as the high-frequency magnetic flux vector generated in response to the application of the high-frequency voltage vectors Vdh * , Vqh * .

[0045] Based on the high-frequency angular frequency ωh * , the D-factor filter b13 detects the mirror image current vector Ihn included in the high-frequency d-axis current Idh and the high-frequency q-axis current Iqh. The mirror image current vector Ihn rotates in the same direction as the high-frequency magnetic flux vector generated in response to the application of the high-frequency voltage vectors Vdh * , Vqh *Rotates in the direction opposite to the high-frequency magnetic flux vector generated in response to the application of

[0046] Here, the D-factor filters b12 and b13 perform the same function as a filter with a frequency characteristic F(s + jωh * ) for each scalar signal that is a component of the 2×1 vector. Therefore, by designing F(s) to have a low-pass characteristic and applying it to the D-factor filters b12 and b13, the D-factor filters b12 and b13 will function as band-pass filters centered at ωh * . Furthermore, the D-factor filters b12 and b13 have the characteristic of polarity separation. That is, due to the band-pass characteristics of polarity separation in the D-factor filters b12 and b13, the high-frequency d-axis current Idh and the high-frequency q-axis current Iqh can be separated into an in-phase current vector Ihp and a mirror-image current vector Ihn

[0047] The mirror-image estimator 302 calculates the axis error Δθ according to equations (5) and (6) based on the in-phase current vector Ihp and the mirror-image current vector Ihn. That is, the mirror-image estimator 302 calculates the arctangent of the synthetic vector obtained by vector addition of the in-phase current vector Ihp and the mirror-image current vector Ihn with the same norm as the axis error Δθ

Equation

Equation

[0048] <Configuration of the drive component removal filter> Figure 5 is a diagram showing a configuration example of the drive component removal filter according to Embodiment 1 of the present disclosure. In Figure 5, the drive component removal filter 50a includes a high-pass filter 50a1 (the first filter of the present invention), a filter constant calculator 50a2, a low-pass filter 50a3 (the second filter of the present invention), and a notch filter 50a4 (the third filter of the present invention).

[0049] Here, the in-phase mirror image current vector generator 301 included in the axis error calculator 30 functions as a band-pass filter. In a band-pass filter, the wider the pass frequency band, the faster the response speed of the filter.

[0050] However, due to the relationship of the sampling frequency based on the carrier frequency in the motor control device 100a, it may be difficult to sufficiently separate the frequency band of the non-high-frequency current and the frequency band of the high-frequency current (Reason 1). For example, since the calculation of the axis error is performed every one cycle of the carrier signal, when the high-frequency current frequency fh * is a high value close to the carrier frequency, the sampling frequency per cycle of the high-frequency current decreases, and the accuracy of position estimation deteriorates. Therefore, the high-frequency current frequency fh * is preferably a frequency sufficiently lower than the carrier frequency (for example, a frequency that is one-twentieth of the carrier frequency).

[0051] Also, since the magnitudes of the voltage and current of the drive component that contributes to torque generation change according to the drive conditions (load, rotation speed, etc.) of the motor M, even under the conditions where the voltage and current of the drive component are maximized, the drive component frequency band (that is, the frequency band other than the high-frequency current frequency fh * band) needs to ensure an attenuation amount such that the drive component current (that is, the non-high-frequency current) can be sufficiently removed (Reason 2).

[0052] Furthermore, with the driving of the motor, a high-frequency current component corresponding to the rotational speed of the motor is generated mainly due to the cogging torque of the motor. Hereinafter, the high-frequency current component generated due to the cogging torque of the motor may be referred to as "cogging current". The order of the frequency of the cogging current is determined according to the number of poles of the rotor of the motor M (hereinafter sometimes referred to as "number of rotor poles") and the number of slots of the motor M (hereinafter sometimes referred to as "number of motor slots"). For example, when the motor M is a motor with P poles and S slots, a cogging current with a frequency that is the least common multiple of P and S is generated. Furthermore, cogging currents with frequencies of 1 / 2 times, 2 times, 3 times, …, n times the least common multiple of P and S are also generated. For example, when the motor M is a 6-pole 9-slot motor, in addition to the 18th-order frequency which is the least common multiple of 6 and 9, a 9th-order frequency which is 1 / 2 times the least common multiple of 6 and 9, and cogging currents with frequencies of 36th, 54th, …, i.e., 18×nth order are generated. Such cogging current degrades the position estimation accuracy, so it is necessary to ensure an attenuation amount that can sufficiently remove the cogging current (Reason 3).

[0053] Then, due to the above Reasons 1, 2, and 3, it becomes necessary to narrow the pass frequency band of the in-phase mirror-image current vector generator 301 as the band-pass filter, and the filter response speed of the in-phase mirror-image current vector generator 301 becomes slow.

[0054] Therefore, in order to input the high-frequency d-axis current Idh and the high-frequency q-axis current Iqh into the in-phase mirror-image current vector generator 301, as shown in FIG. 5, the drive component removal filter 50a includes a high-pass filter 50a1, a filter constant calculator 50a2, a low-pass filter 50a3, and a notch filter 50a4. When the high-frequency d-axis current Idh and the high-frequency q-axis current Iqh are input into the in-phase mirror-image current vector generator 301, the current input into the in-phase mirror-image current vector generator 301 becomes only the high-frequency current generated by the high-frequency voltage for estimating the rotor position. In this way, by combining the high-pass filter 50a1, the low-pass filter 50a3, and the notch filter 50a4 to form a band-pass filter, it becomes possible to widen the pass frequency band of the in-phase mirror-image current vector generator 301 as a band-pass filter. Therefore, compared with the case of using a band-pass filter with a narrow pass frequency band as the in-phase mirror-image current vector generator 301, the filter response speed can be increased.

[0055] In FIG. 5, the high-pass filter 50a1 obtains the drive-current-removed d-axis current Id1 and the drive-current-removed q-axis current Iq1 after removing the drive current component (hereinafter sometimes referred to as "drive current") Im that contributes to the torque generation of the motor M from the d-axis current Id and the q-axis current Iq. The drive current Im is a current component generated accompanying the driving of the motor M by the drive voltage command value Vm. For example, it is preferable that the pass frequency band of the high-pass filter 50a1 be a frequency band equal to or higher than a frequency sufficiently higher than the mechanical angular velocity command value ωm * (for example, a frequency four times or higher than the mechanical angular velocity command value ωm * ).

[0056] When the drive current Im is removed by the high-pass filter 50a1, a phase shift occurs in the high-frequency current (drive-current-removed d-axis current Id1 and drive-current-removed q-axis current Iq1). Equation (7) shows the phase characteristic θhigh of the high-pass filter 50a1. In Equation (7), "HIGH_a0" is a predetermined filter constant of the high-pass filter 50a1. From Equation (7), the amount of phase shift in the high-frequency current frequency fh * band can be grasped.

Equation

[0057] On the other hand, the phase characteristic θlow of the high-frequency current frequency fh * band of the low-pass filter 50a3 is represented by Equation (8). In Equation (8), "LOW_a0" is the filter constant of the low-pass filter 50a3.

Equation

[0058] Therefore, the filter constant calculator 50a2 calculates the filter constant LOW_a0 of the low-pass filter 50a3 according to Equations (9) and (10) based on the high-frequency angular frequency ωh * and the filter constant HIGH_a0 of the high-pass filter 50a1. The filter constant LOW_a0 is updated as needed with the change in the high-frequency angular frequency ωh * . The filter constant LOW_a0 calculated by the filter constant calculator 50a2 is set in the low-pass filter 50a3.

Equation

Equation

[0059] The low-pass filter 50a3 performs filtering processing on the drive-current-removed d-axis current Id1 and the drive-current-removed q-axis current Iq1 using the filter constant LOW_a0 calculated by the filter constant calculator 50a2. As a result, the phase shift generated in the drive-current-removed d-axis current Id1 and the drive-current-removed q-axis current Iq1 is compensated, and high-frequency noise Inoise is removed from the drive-current-removed d-axis current Id1 and the drive-current-removed q-axis current Iq1. The high-frequency noise Inoise is generated in a frequency band higher than the frequency of the high-frequency current Ih as the motor M is driven. The low-pass filter 50a3 outputs the noise-removed d-axis current Id2 and the noise-removed q-axis current Iq2 after the filtering processing to the notch filter 50a4.

[0060] The notch filter 50a4 obtains the high-frequency d-axis current Idh and the high-frequency q-axis current Iqh by removing the cogging current of the cogging frequency fcog from the noise-removed d-axis current Id2 and the noise-removed q-axis current Iq2. The cogging frequency fcog is calculated by dividing the multiplication result of the least common multiple of the rotor pole number P and the motor slot number S and the mechanical angular velocity command value ωm * by 2π, and the cogging frequency fcog is set as the center frequency of the attenuation band of the notch filter 50a4. The cogging frequency fcog is updated as needed along with the change in the mechanical angular velocity command value ωm * .

Equation

[0061] As described above, the drive-component removal filter 50a obtains the high-frequency current Ih by removing non-high-frequency currents from the d-axis current Id and the q-axis current Iq. For example, the drive current Im, the high-frequency noise Inoise, and the cogging current correspond to non-high-frequency currents that are current components generated as the motor M is driven.

[0062] <Operation of the drive-component removal filter> Figures 6, 7, 8, and 9 are diagrams showing operation examples of the drive component removal filter according to Embodiment 1 of the present disclosure. The d-axis current Id and q-axis current Iq input to the drive component removal filter 50a include a drive current Im, a cogging current, a high-frequency current Ih, and a high-frequency noise Inoise.

[0063] As shown in FIG. 6, the high-pass filter 50a1 removes the drive current Im from the d-axis current Id and the q-axis current Iq with a cut-off frequency that is, for example, four times the mechanical angular velocity command value ωm * of the frequency.

[0064] Next, the low-pass filter 50a3 compensates for the phase shift generated in the d-axis current Id1 with drive current removed and the q-axis current Iq1 with drive current removed using the filter constant LOW_a0 calculated by the filter constant calculator 50a2. At the same time as the phase shift is compensated, as shown in FIG. 7, the high-frequency noise Inoise is removed from the d-axis current Id1 with drive current removed and the q-axis current Iq1 with drive current removed.

[0065] Next, as shown in FIG. 8, the notch filter 50a4 removes the cogging current at the cogging frequency fcog from the d-axis current Id2 with noise removed and the q-axis current Iq2 with noise removed, with the cogging frequency fcog as the center frequency of the attenuation band.

[0066] Through the above-described filtering processes in the high-pass filter 50a1, the low-pass filter 50a3, and the notch filter 50a4, as shown in FIG. 9, the high-frequency current Ih is extracted from the d-axis current Id and the q-axis current Iq.

[0067] As described above, since the drive current Im is removed by the high-pass filter 50a1, the current input to the in-phase mirror image current vector generator 301 does not include the drive current Im. As a result, the pass frequency band of the in-phase mirror image current vector generator 301 as a band-pass filter can be widened, so that the rotor position can be accurately estimated without reducing the filter response speed in the in-phase mirror image current vector generator 301.

[0068] In addition, since the low-pass filter 50a3 performs filtering using the filter constant LOW_a0 calculated according to Equation (10), it is possible to prevent a phase shift from occurring in the current input to the in-phase mirror-image current vector generator 301, and thus it is possible to further prevent a decrease in position estimation accuracy. Further, since the high-frequency noise Inoise is removed by the low-pass filter 50a3, it is possible to prevent a decrease in position estimation accuracy.

[0069] In addition, since the cogging current is removed by the notch filter 50a4, it is possible to further prevent a decrease in position estimation accuracy.

[0070] <Operation of High-Frequency Voltage Removal Filter> Since the calculation of the axis error is performed every one cycle of the carrier signal, if the high-frequency current frequency fh * is a high value close to the carrier frequency, the number of samplings per cycle of the high-frequency current decreases, and the accuracy of position estimation decreases. Therefore, the high-frequency current frequency fh * is preferably a frequency sufficiently lower than the carrier frequency (for example, a frequency that is one-twentieth of the carrier frequency). For this reason, there are cases where it is difficult to sufficiently separate the frequency band of the non-high-frequency current from the frequency band of the high-frequency current.

[0071] In addition, due to the generation of the cogging current, there may already be fluctuations near the high-frequency current frequency fh * in the driving voltage command value Vm before the d-axis high-frequency voltage command value Vdh * and the q-axis high-frequency voltage command value Vqh * are superimposed. If there are fluctuations near the high-frequency current frequency fh * in the driving voltage command value Vm, the high-frequency voltage vector applied to the motor M for estimating the rotor position will not draw a perfect circle on the d-q coordinate axes, and the position estimation accuracy will decrease.

[0072] Therefore, as shown in FIG. 10, the high-frequency voltage removal filters 61 and 62 realized according to Equation (1) have a high-frequency current frequency fh* Using the center frequency of the attenuation band as the high-frequency current frequency fh * By removing the high-frequency components in the high-frequency band from the driving voltage command value Vm, as shown in FIG. 11, the high-frequency removal driving voltage command value Vm is obtained from the driving voltage command value Vm * is extracted. FIGS. 10 and 11 are diagrams showing operation examples of the high-frequency voltage removal filter according to the first embodiment of the present disclosure. From the driving voltage command value Vm, the high-frequency current frequency fh * Since the high-frequency components in the band are removed, the high-frequency voltage vector applied to the motor M for estimating the rotor position draws a perfect circle on the d-q coordinate axes, so that a decrease in the position estimation accuracy can be prevented.

[0073] Note that, in order to remove all current components in the frequency band near the frequency of the high-frequency voltage from the current input to the current controller 20, it is conceivable to widen the cutoff band of the high-frequency removal filters 41 and 42. However, for example, when removing high-frequency components using a notch filter or the like, widening the cutoff band causes a phase shift in the current components that are not removed. This phase shift increases as the cutoff band of the filter is widened. Also, it is conceivable to prevent the generation of high-frequency components by slowing down the response of the current controller 20. However, if the response of the current controller 20 is slowed down, the stability of the drive control of the motor M will decrease. Therefore, it is preferable to provide high-frequency removal filters 61 and 62 between the current controller 20 and the adders 44 and 45 so as not to have a significant impact on the drive control of the motor M.

[0074] The above describes the first embodiment.

[0075] [Second Embodiment] In the second embodiment, the difference from the first embodiment is that filtering processing is performed based on the mechanical angle estimation angular velocity ωm_iir after removing the fluctuation component of the mechanical angle estimation angular velocity ωm. Hereinafter, the differences from the first embodiment will be described.

[0076] <Configuration of Motor Control Device> FIG. 12 is a diagram showing a configuration example of the motor control device according to Embodiment 2 of the present disclosure. In FIG. 12, the motor control device 100b includes an IIR filter 51 and a drive component removal filter 50b.

[0077] The IIR filter 51 removes the fluctuation component of the mechanically estimated angular velocity ωm output from the 1 / Pn processor 33, and outputs the mechanically estimated angular velocity ωm_iir after removing the fluctuation component to the drive component removal filter 50b.

[0078] The drive component removal filter 50b extracts the high-frequency current Ih from the d-axis current Id and the q-axis current Iq by removing the non-high-frequency current from the d-axis current Id and the q-axis current Iq based on the mechanically estimated angular velocity ωm_iir and the high-frequency angular frequency ωh * and.

[0079] <Configuration of drive component removal filter> FIG. 13 is a diagram showing a configuration example of the drive component removal filter according to Embodiment 2 of the present disclosure. In FIG. 13, the drive component removal filter 50b includes a high-pass filter 50a1, a filter constant calculator 50a2, a low-pass filter 50a3, and a notch filter 50b4 (the third filter of the present invention).

[0080] In FIG. 13, the notch filter 50b4 obtains the high-frequency d-axis current Idh and the high-frequency q-axis current Iqh by removing the cogging current of the cogging frequency fcog from the noise-removed d-axis current Id2 and the noise-removed q-axis current Iq2. The cogging frequency fcog is calculated by dividing the multiplication result of the least common multiple of the rotor pole number P and the motor slot number S and the mechanically estimated angular velocity ωm_iir by 2π, as shown in Equation (12).

Equation

[0081] As described above, the drive component removal filter 50b obtains the high-frequency current Ih by removing the non-high-frequency current from the d-axis current Id and the q-axis current Iq, similarly to the drive component removal filter 50a of Embodiment 1.

[0082] As described above, even if filtering processing is performed using the mechanical angular velocity estimated value ωm_iir as a parameter representing the rotational speed of the motor M instead of the mechanical angular velocity command value ωm, it is possible to prevent a decrease in the position estimation accuracy as in the first embodiment. * Even if filtering processing is performed using the mechanical angular velocity estimated value ωm_iir as a parameter representing the rotational speed of the motor M instead of the mechanical angular velocity command value ωm, it is possible to prevent a decrease in the position estimation accuracy as in the first embodiment.

[0083] The second embodiment has been described above.

[0084] As described above, the motor control device (the motor control devices 100a and 100b of the embodiments) of the present disclosure includes a calculator (adders 44 and 45 of the embodiments), an axis error calculator (axis error calculator 30 of the embodiments), a current calculator (3φ current calculator 28 of the embodiments), a converter (u, v, w / d-q converter 29 of the embodiments), and a drive component removal filter (drive component removal filters 50a and 50b of the embodiments). The calculator generates a drive voltage command value (d-axis drive voltage command value Vdm and q-axis drive voltage command value Vqm of the embodiments) for driving the motor (motor M of the embodiments) at a desired rotational speed and a high-frequency voltage command value (d-axis high-frequency voltage command value Vdh * , q-axis high-frequency voltage command value Vqh * ) for generating a high-frequency current (high-frequency current Ih of the embodiments) used for estimating the rotor position of the motor, and calculates a voltage command value (d-axis voltage command value Vd * , q-axis voltage command value Vq * ) based on these. The axis error calculator calculates an axis error (axis error Δθ of the embodiments) using the high-frequency current generated in response to the application of the high-frequency voltage command value. The current calculator calculates a three-phase current including the high-frequency current. The converter converts the three-phase current into a two-phase current including the high-frequency current. The drive component removal filter extracts the high-frequency current from the two-phase current by removing a current component (non-high-frequency current of the embodiments) generated due to the driving of the motor from the two-phase current.

[0085] For example, the drive component removal filter includes a first filter (high-pass filter 50a1 of the embodiments) that removes a current component (drive current Im of the embodiments) generated by the drive voltage command value.

[0086] For example, the drive component removal filter further includes a second filter (low-pass filter 50a3 in the embodiment) that compensates for the phase shift generated in the high-frequency current by the first filter and removes high-frequency noise (high-frequency noise Inoise in the embodiment) in a frequency band higher than the frequency of the high-frequency current.

[0087] For example, the drive component removal filter further includes a third filter (notch filters 50a4 and 50b4 in the embodiment) that removes a current component (cogging current in the embodiment) in a frequency band based on a frequency calculated by dividing the product of the least common multiple of the number of poles of the rotor of the motor and the number of slots of the motor and the rotational speed of the motor (mechanical angular velocity command value ωm * , mechanical angular velocity estimation ωm_iir) of the motor by 2π (cogging frequency in the embodiment).

[0088] Further, the motor control device (motor control devices 100a and 100b in the embodiment) of the present disclosure further includes a high-frequency voltage removal filter (high-frequency voltage removal filters 61 and 62 in the embodiment) that removes high-frequency components from the drive voltage command value.

Description of Reference Numerals

[0089] 100a, 100b Motor control devices 50a, 50b Drive component removal filters 50a1 High-pass filter 50a2 Filter constant calculator 50a3 Low-pass filter 50a4, 50b4 Notch filters 61, 62 High-frequency voltage removal filters

Claims

1. A calculator that calculates a voltage command value based on a drive voltage command value for driving a motor at a desired rotational speed and a high-frequency voltage command value for generating a high-frequency current used for estimating the rotor position of the motor; An axis error calculator that calculates an axis error using the high-frequency current generated in response to the application of the high-frequency voltage command value; A current calculator that calculates a three-phase current including the high-frequency current; A converter that converts the three-phase current into a two-phase current including the high-frequency current; A drive component removal filter that extracts the high-frequency current from the two-phase current by removing a current component generated along with the driving of the motor from the two-phase current; Comprising; The drive component removal filter further has a third filter that removes a current component in a frequency band based on a frequency calculated by dividing the product of the least common multiple of the number of poles of the rotor of the motor and the number of slots of the motor and the rotational speed of the motor by 2π. A motor control device.

2. The drive component removal filter has a first filter that removes a current component generated by the drive voltage command value. The motor control device according to claim 1. The motor control device according to claim 1.

3. The drive component removal filter further has a second filter that compensates for a phase shift generated in the high-frequency current by the first filter and removes high-frequency noise in a frequency band higher than the frequency of the high-frequency current. The motor control device according to claim 2. The motor control device according to claim 2.

4. Further comprising a high-frequency voltage removal filter that removes a high-frequency component from the drive voltage command value. The motor control device according to claim 1. The motor control device according to claim 1.

5. A calculator that calculates a voltage command value based on a drive voltage command value for driving a motor at a desired rotational speed and a high-frequency voltage command value for generating a high-frequency current used for estimating the rotor position of the motor; An axis error calculator that calculates an axis error using the high-frequency current generated in response to the application of the high-frequency voltage command value; A current calculator that calculates a three-phase current including the high-frequency current; A converter that converts the three-phase current into a two-phase current including the high-frequency current; A drive component removal filter that extracts the high-frequency current from the two-phase current by removing a current component generated along with the driving of the motor from the two-phase current; A high-frequency voltage removal filter that removes a high-frequency component from the drive voltage command value; A motor control device comprising.

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