JP2019106768A - Motor control device - Google Patents

Abstract

To reduce vibration or the like caused by load torque fluctuation by reducing a conversion error of an axis error fluctuation component.SOLUTION: A motor control device comprises: an axis error calculator which calculates an axis error between a control axis of a motor and a real axis; a speed estimator which estimates an average estimation speed of the motor from the axis error; a speed fluctuation generator which generates speed fluctuation of the motor from the axis error; and a position estimator which estimates a rotation angle position of the motor from an estimation speed resulting from adding the average estimation speed and the speed fluctuation. The speed fluctuation generator generates the speed fluctuation of the motor from the axis error calculated by the axis error calculator and a mechanical angle phase of the motor estimated by the position estimator.SELECTED DRAWING: Figure 7

Description

  The present invention relates to a motor control device.

The angular velocity ω of the rotating sensorless three-phase motor is the rotation angle position (estimated rotation angle position) θ _{dc of the} estimated control axis (dc-qc axis) and the rotation of the actual axis (dq axis) which is the actual rotation axis the axis error Δθ is the difference between the angular position theta _d is calculated by proportional integral (PI). In the control system of the sensorless three-phase motor, the calculated angular velocity ω is fed back to adjust the angular velocity ω so that the axis error Δθ approaches zero. The angular velocity ω obtained in this way is used for comparison with the angular velocity command value ω ^*, and the electrical angle of the rotor estimated by integrating the angular velocity ω to estimate the electrical angle phase θ _e of the rotor 3-phase using the phase _{θ e (U, V, W} ) / 2 phase (d-q) conversion, and 2-phase / 3-phase conversion of the reverse takes place.

JP, 2016-82637, A

  Among the motors, there is a motor for driving a compressor used in an air conditioner or the like. In the compressor, the load torque periodically fluctuates during one rotation of the rotor of the motor that drives the compressor due to the pressure change of the gas refrigerant in the suction, compression, and discharge strokes. Since this cyclic load torque fluctuation is a factor that causes the motor speed to fluctuate to generate vibration and noise, torque correction to suppress cyclic load torque fluctuation is generally performed.

  However, since this torque correction allows speed fluctuation to such an extent that vibration and noise do not pose a practical problem from the viewpoint of power consumption reduction and overcurrent prevention, the actual angular velocity is the load torque and motor output. It fluctuates periodically due to the difference with the torque, and the axis error Δθ also fluctuates periodically. The estimated angular velocity ω calculated from the axis error Δθ is calculated by proportionally integrating (PI) the axis error Δθ by the velocity estimator (PLL). Therefore, although the average angular velocity of the estimated angular velocity ω can be estimated, it is instantaneous There is an amplitude and phase shift between the actual angular velocity and this, and this amplitude and phase shift periodically fluctuates. That is, the estimated angular velocity ω and the actual angular velocity are not synchronized. As a result, the fluctuation of the axis error Δθ continues to occur.

  In a control system that performs torque control of a three-phase motor by position sensorless vector control, the position estimator estimates the position of the rotor based on the above estimated angular velocity ω, and generates a torque command value based on the estimated rotor position. And 3 phase / 2 phase conversion and 2 phase / 3 phase conversion. Therefore, if there is a periodically varying amplitude and phase shift between the estimated angular velocity ω and the actual angular velocity, the error in the torque command value resulting from it, the three-phase / two-phase conversion, and the two-phase / three-phase conversion Conversion errors occur. As a result, a phase shift periodically changing between the control axis (dc-qc axis) to be estimated and the actual rotation axis (dq axis) remains, and the axis error Δθ is zero even if feedback control is repeated. As a result, there is a problem that motor vibration or step out occurs.

  The present invention has been made in view of the above, and eliminates the periodic fluctuation of the amplitude and phase shift between the estimated angular velocity and the actual angular velocity and synchronizes them, thereby causing the fluctuation of the axis error Δθ. To provide a motor control device that suppresses motor vibration and step out.

  In order to solve the problems described above, an example of the embodiment of the present invention is an axis error computing unit that computes an axis error between a control axis of a motor and a real axis, and a speed estimation that estimates an average estimated speed of the motor from the axis error. , A velocity fluctuation generator that generates a motor velocity fluctuation from an axis error, and a position estimator that estimates a rotational angle position of the motor from an estimated velocity obtained by adding the average estimated velocity and the speed fluctuation.

  According to an embodiment of the present invention, by synchronizing the estimated speed of the motor with the actual speed, the error due to the three-phase / two-phase conversion and vice versa is reduced, and as a result Vibration and the like due to load torque fluctuation can be suppressed.

FIG. 1 is a diagram for explaining an example of speed estimation means according to the prior art. FIG. 2 is a diagram for explaining an example of the process of speed estimation in the prior art. FIG. 3 is a diagram for explaining an example of error generation in two-phase / three-phase conversion and three-phase / two-phase conversion in the prior art. FIG. 4 is a diagram for explaining an example of a means for suppressing the fluctuation of the axis error according to the disclosed technique. FIG. 5 is a diagram for explaining an example of a process in which the variation in axis error is suppressed in the disclosed technique. FIG. 6 is a block diagram showing an example of a motor control device according to Embodiment 1 (and Embodiment 2). FIG. 7 is a block diagram showing an example of the speed fluctuation generator according to the first embodiment. FIG. 8 is a block diagram showing an example of the speed fluctuation generator according to the second embodiment. FIG. 9 is a view showing an example of a demodulation phase table of axis error correction according to the second embodiment.

  An example of an embodiment of a motor control device according to the disclosed technology will be described below with reference to the attached drawings. In the following embodiments, torque control of a permanent magnet synchronous motor (PMSM (Permanent Magnet Synchronous Motor)) for driving a compressor having periodic load torque fluctuation is performed by position sensorless vector control, for example, an air conditioner or low temperature The present invention relates to a motor control device such as a storage device. However, the disclosed technology is widely applicable to motor control devices that perform torque control of a motor that drives a load having periodic load torque fluctuations. Moreover, when it only describes as speed by the following description, unless otherwise indicated, it represents angular velocity.

  Note that the embodiments described below do not limit the disclosed technology. In addition, the embodiments described below and the modifications thereof can be combined as appropriate without causing any contradiction. In addition, embodiments shown below mainly show configurations and processes according to the disclosed technology, and description of the other configurations and processes is simplified or omitted. Moreover, in each embodiment, the same code | symbol is provided to the same structure and process, and description of an existing structure and process is abbreviate | omitted.

  In addition, the list of the description of the symbol used below is shown in the following (Table 1).

[Summary of prior art]
Prior to the description of the embodiments, an outline of the prior art will be described. FIG. 1 is a diagram for explaining an example of speed estimation means according to the prior art. FIG. 2 is a diagram for explaining an example of the process of speed estimation in the prior art. FIG. 3 is a diagram for explaining an example of error generation in two-phase / three-phase conversion and three-phase / two-phase conversion in the prior art.

As shown in FIG. 1, in the prior art, an axis error Δθ is input to a velocity estimator (PLL (Phase Locked Loop)), and proportional integration (PI) is performed by the velocity estimator. An electrical angle estimated angular velocity ω _e is generated such that the error Δθ approaches zero. Then, the electric angle estimated angular velocity ω _e is integrated by the position estimator to generate an electric angle phase θ _e . Since the current estimated position of the rotor is ahead of the actual position if the axis error Δθ is positive, the speed estimator reduces the output electrical angle estimated angular velocity ω _e and the axis error Δθ is negative. For example, since the current estimated position of the rotor is behind the actual position, the output electrical angle estimated angular velocity ω _e is increased.

In the configuration shown in FIG. 1, although the electrical angle estimated angular velocity ω _e can be estimated as an average angular velocity by proportional integral (PI) of the axis error Δθ, as described above, the instantaneous values of the actual electrical angular velocity and the electrical angle estimated angular velocity ω _e Amplitude and phase do not match. Therefore, the fluctuation component of the axis error Δθ remains, and the axis error Δθ continues to fluctuate as shown in FIG. Note that ω _e in FIG. 2 is an estimated electrical angle velocity generated as an angular velocity that brings the axis error Δθ close to zero by performing proportional integration (PI) of the axis error Δθ. The electric angle estimated angular velocity ω _e generated in this manner is fed back for each carrier period.

By axial error Δθ fluctuates, as shown in FIG. 3, the error occurs in the electrical angle estimate angular velocity omega _e, errors occur in more electrical angle phase theta _e. Therefore, the 3-phase / 2-phase conversion in a two-phase / three-phase conversion and UVW / dq converter in the dq / UVW converter using electrical angle phase theta _e, conversion error is generated.

[Technology of disclosure]
FIG. 4 is a diagram for explaining an example of a means for suppressing the fluctuation of the axis error according to the disclosed technique. FIG. 5 is a diagram for explaining an example of a process in which the variation in axis error is suppressed in the disclosed technique.

The technique disclosed in the present application, a rotational angular position (the estimated rotational angular position) theta _dc of the estimated control shaft (dc-qc axis), and the rotational angular position theta _dq of the actual rotation axis real axis (dq axis) Is separated from the axis error .DELTA..theta., Which is the difference between them, and the speed fluctuation .DELTA..omega. _E is generated from the separated axis error fluctuation component. The speed variation [Delta] [omega _e, the estimated speed as an estimated speed that is corrected by adding the outputted average estimated speed omega _e0 by the speed estimator (hereinafter, also referred to as electrical angle estimate angular velocity) for the control of the motor controller obtains the omega _e By applying, the fluctuation of the axis error Δθ is suppressed. Specifically, as shown in FIG. 4, the speed fluctuation generator connected in parallel with the speed estimator is provided in the front stage of the position estimator. The velocity fluctuation generator receives the axis error Δθ and the mechanical angle phase θ _m output by the position estimator, and generates a velocity fluctuation Δω _e .

Then, as shown in FIG. 5, a speed fluctuation is generated for each cycle (load torque fluctuation cycle) T of one rotation of the motor rotor, and the phase of the speed fluctuation is delayed by π / 2 and output as a speed fluctuation Δω _e The next estimated period is added to the average estimated velocity ω _e0 output by the velocity estimator to generate an estimated electrical angular velocity ω _e . The electrical angle estimate angular velocity omega _e applied to the control of the motor control device, by performing feedback control, to suppress the fluctuation of the axis error [Delta] [theta].

Note that the fluctuation of the axial error Δθ can be suppressed by using the estimated electrical angular velocity ω _e obtained by adding the velocity fluctuation Δω _e delayed in phase by, for example, π / 2 to the axial error Δθ. The fluctuation of the rotor position θ delayed by π / 2 phase with respect to the speed fluctuation Δω _e further delayed by π / 2 phase becomes the phase inverted with respect to the fluctuation of axial error Δθ, and the fluctuation of axial error Δθ Is offset. The rotor position θ changes with a delay of π / 2 with respect to the speed fluctuation Δω _e , as is apparent from the fact that the rotor position θ is expressed by the integral of the rotor angular velocity ω, as shown in the following equation (1).

Embodiment 1
(Motor control device according to the first embodiment)
FIG. 6 is a block diagram showing an example of the motor control device according to the first embodiment. In the first embodiment, the fluctuation component of the axis error Δθ is separated to calculate the speed fluctuation, and the phase of the calculated speed fluctuation is delayed by π / 2 and added to the average estimated speed of the next cycle obtained from the axis error Δθ. The electric angle estimated angular velocity is estimated such that the axis error Δθ approaches zero.

The motor control device 100 according to the first embodiment controls the motor 10. The motor control device 100 is configured to add the velocity fluctuation Δω _e generated by the velocity fluctuation generator to the average estimated velocity ω _e0 that is the output of the velocity estimator to generate the estimated electrical angular velocity ω _e .

The motor control device 100 includes subtractors 11, 16 and 17, a speed controller 12, adders 13, 19, 20 and 32, a current command generator 14, a correction torque generator 15, and a voltage command generator 18. The motor control device 100 further includes a dq / u, v, w converter (two-phase / three-phase converter) 21, a PWM (Pulse Width Modulation) modulator 22, and an IPM (Intelligent Power Module) 23. The motor control device 100 also includes a shunt resistor 26 (or current sensor 24, 25), a 3φ current calculator 27, u, v, w / d-q converter (three-phase / two-phase converter) 28, axis error The arithmetic unit 29, the speed estimator (PLL) 30, the speed fluctuation generator 31, the position estimator 33, the non-interference controller 34, and the 1 / P _n processor 35 are provided.

Subtractor 11 subtracts the mechanical angle estimated angular velocity ω _m which is the current estimated angular velocity output by 1 / P n processor 35 from the mechanical angular velocity command value ω _m ^* input to motor control device 100, and the angular velocity deviation Δω Is output to the speed controller 12.

The speed controller 12 generates and outputs an average torque command value T ₀ ^* such that the angular velocity deviation Δω input from the subtractor 11 is reduced. The adder 13 outputs a total torque command value T ^* obtained by adding the average torque command value T ₀ ^* output by the speed controller 12 and the fluctuation torque command value ΔT output by the correction torque generator 15.

The current command generator 14 generates and outputs a d-axis current command value I _d ^* and a q-axis current command value I _q ^* from the total torque command value T ^* output from the adder 13. Specifically, the current command generator 14 generates a d-axis current command value I _d ^* and a q-axis current command value I _q ^* on the dq coordinate axis from the total torque command value T ^* . The d-axis current command value I _d ^* and the q-axis current command value I _q ^* are generated to be values on the maximum torque / current curve, for example, in the normal control region where the motor voltage is not in the voltage saturation region If the voltage is in the voltage saturation region, it is generated to be a value on the induced voltage ellipse.

The correction torque generator 15 estimates a mechanical angle which is a periodical speed fluctuation in one rotation of the motor included in the mechanical angle estimated angular velocity ω _m outputted by the speed fluctuation allowance value | Δω _m | ^* , 1 / P n processor 35. From the angular velocity fluctuation Δω _m and the mechanical angular phase θ _m outputted by the position estimator 33, a fluctuation torque command value ΔT for suppressing the periodic velocity fluctuation Δω _e is generated. The fluctuation torque command value ΔT is adjusted in consideration of power consumption reduction, prevention of demagnetization of the motor 10, and the like. Here, the mechanical angle phase θ _m is the rotational angle position of the motor (rotor) represented by the mechanical angle.

The subtractor 16 subtracts the d-axis current Id output by the u, v, w / d-q converter 28 from the d-axis current command value I _d ^* output by the current command generator 14 The deviation ΔId is output. Subtractor 17, the q-axis current command value _I ^{q *} outputted by the current command generator 14, u, v, q-axis obtained by subtracting the outputted q-axis current _{I q} by w / d-q converter 28 The current deviation ΔI _q is output.

The voltage command generator 18 uses the d-axis current deviation ΔI _d output from the subtractor 16 and the q-axis current deviation Δ I _q output from the subtracter 17 to generate a non-interference d-axis voltage command value V _dt before interference. A non-interference q-axis voltage command value V _qt is generated.

The adder 19 includes a non-interference before d-axis voltage command value V _dt output by the voltage command generator 18, output by the non-interference controller 34, a non-interference before d-axis voltage command value V _dt A d-axis voltage command value V _d ^* obtained by adding the non-interference correction value V _da for the non-interference generation is output. The adder 20 includes a q-axis voltage command value V _qt decoupling before output by the voltage command generator 18, output by the non-interference controller 34, a non-interference before the q-axis voltage command value V _qt A q-axis voltage command value V _q ^* obtained by adding the non-interference correction value V _qa to be corrected is output.

The dq / u, v, w converter 21 uses the electrical angle phase θ _e that is the current rotor position output from the position estimator 33 to generate two-phase d output from the adders 19 and 20. Axis voltage command value V _d ^* and q-axis voltage command value V _q ^* to 3-phase U phase output voltage command value V _U ^* , V phase output voltage command value V _V ^* , W phase output voltage command value V _W ^* Convert. The dq / u, v, w converter 21 converts the U-phase output voltage command value V _U ^* , the V-phase output voltage command value V _V ^* , and the W-phase output voltage command value V _W ^* into the PWM modulator 22. Output to The PWM modulator 22 generates a six-phase PWM signal from the U-phase output voltage command value V _U ^* , the V-phase output voltage command value V _V ^* , the W-phase output voltage command value V _W ^*, and the PWM carrier signal. Output to the IPM 23.

The IPM 23 converts the DC voltage V _dc supplied from the outside based on the six-phase PWM signal output from the PWM modulator 22 and applies it to the U-phase, V-phase and W-phase of the motor 10 respectively. An AC voltage is generated, and each AC voltage is applied to the U phase, the V phase, and the W phase of the motor 10.

When the 3φ current calculator 27 measures the bus current in the one-shunt method, the U-phase of the motor 10 is obtained from the 6-phase PWM switching information output by the PWM modulator 22 and the measured bus current. The current value I _U , the V-phase current value I _V , and the W-phase current value I _W are calculated.

Alternatively, the method of measuring the current is not limited to one shunt method of measuring the bus current, but two CTs (Current Transformers), for example, the current of the U phase of the motor 10 by the current sensor 24 and the motor of the current sensor 25 The current of 10 V phases may be measured. 3φ current calculator 27, when measured U-phase current and V-phase current by the current sensor 24, 25 and two CT, the remaining W-phase current values _{I w,} the Kirchhoff of _{I U + I V + I W} = 0 Calculated from the law. The 3φ current calculator 27 outputs the calculated phase current value I _U , I _V , I _W of each phase to the u, v, w / dq converter 28.

The u, v, w / d-q converter 28 outputs the 3-phase U-phase current value I _U output by the 3φ current calculator 27 based on the electrical angle phase θ _e output by the position estimator 33. , V-phase current value I _V , and W-phase current value I _W are converted into two-phase d-axis current I _d and q-axis current I _q . The u, v, w / dq converter 28 sends the d-axis current I _d to the subtractor 16, the axis error calculator 29, the non-interference controller 34 and the q-axis current I _q to the subtractor 17, It outputs to the non-interference controller 34 and the axis error calculator 29 respectively.

The axis error computing unit 29 outputs the d-axis voltage command value V _d ^* output from the adder 19 and the q-axis voltage command value V _q ^* output from the adder 20, u, v, w / d-q converter The axis error Δθ is calculated from the d-axis current I _d and the q-axis current I _q output by the V.28, and is output to the velocity estimator (PLL) 30 and the velocity fluctuation generator 31, respectively.

The speed estimator (PLL) 30 calculates an average estimated speed ω _e0 that brings the average component of the axis error Δθ closer to zero from the axis error Δθ output by the axis error calculator 29 and outputs the average estimated speed ω _e0 to the adder 32 Do. The velocity fluctuation generator 31 is a velocity that brings the fluctuation component of the axis error Δθ closer to zero from the axis error Δθ output by the axis error calculator 29 and the mechanical angle phase θ _m output by the position estimator 33. Generate a variation Δω _e .

The adder 32 estimates an electrical angle which is an estimated velocity corrected by adding the average estimated velocity ω _e0 output from the velocity estimator (PLL) 30 and the velocity fluctuation Δω _e output from the velocity fluctuation generator 31. An angular velocity ω _e is generated and output. Position estimator 33 estimates the electrical angle phase theta _e and mechanical angular phase theta _m from electrical angle estimate angular velocity omega _e outputted by the adder 32. Then, the position estimator 33 outputs the estimated electrical angle phase θ _e to the dq / u, v, w converter 21 and the u, v, w / dq converter 28, respectively. Further, the position estimator 33 outputs the estimated mechanical angle phase θ _m to the correction torque generator 15 and the speed fluctuation generator 31, respectively.

The non-interference controller 34 estimates the electrical angle after correction of the d-axis current I _d and the q-axis current I _q output by the u, v, w / d-q converter 28 and the adder 32. A non-interference correction value V _da for correcting the pre-interference d-axis voltage command value V _dt is generated from the angular velocity ω _e and output to the adder 19, and the pre-interference q-axis voltage command value V A non-interference correction value V _qa for correcting _qt is generated and output to the adder 20.

1 / Pn processor 35 calculates the mechanical angle estimated angular velocity omega _m of the electrical angle estimate angular velocity omega _e outputted by the adder 32 is divided by the number of pole pairs Pn of the motor 10, the subtracter 11 and the correction torque generator Output to 15 respectively.

(Speed fluctuation generator according to the first embodiment)
FIG. 7 is a block diagram showing an example of the speed fluctuation generator according to the first embodiment. The speed fluctuation generator 31 according to the first embodiment includes an axis error fluctuation component separator 31-1, an axis error fluctuation integrator 31-2, and a speed fluctuation demodulator 31-3.

The axis error fluctuation component separator 31-1 separates the fundamental wave component of the fluctuation from the input axis error Δθ. Specifically, two Fourier coefficients Δθ _sin (sin component) and Δθ _cos (cos component) are calculated from the axis error Δθ from the following equations (2-1) and (2-2) using the mechanical angle phase θ _m It is generated as a fundamental wave component of fluctuation. By accurately calculating the Fourier coefficient of the fundamental wave component of the fluctuation of the axial error Δθ every mechanical angle period, accurately extracting the fundamental wave component of the fluctuation of the axial error Δθ excluding the harmonic component of the fluctuation of the axial error Δθ Can. Δθ _sin and Δθ _cos are values updated every mechanical angle cycle.

The axis error fluctuation integrator 31-2 is a Fourier coefficient Δθ _sin of the fluctuation component of the axis error Δθ separated by the axis error fluctuation component separator 31-1 from the following equations (3-1) and (3-2) and applying the corrected [Delta] [theta] _cos gain k (integral gain for converting the position error [Delta] [theta] to the speed), stores the [Delta] [theta] _sin and [Delta] [theta] _cos in each period. Following (3-1) and (3-2) each of [Delta] [theta] _{Sin_i_old} and [Delta] [theta] _{Cos_i_old} in formula, which is [Delta] [theta] _{Sin_i} and [Delta] [theta] _{Cos_i} in the previous mechanical angle cycle.

The velocity fluctuation demodulator 31-3 calculates the velocity fluctuation Δω _e by the calculation of the following equation (4). By this processing, the accumulation result of the fluctuation of the axis error Δθ by the axis error fluctuation integrator 31-2 is converted to the phase of the speed fluctuation Δω _e delayed by the phase by π / 2, and at the timing of the mechanical angle phase θ _m The instantaneous value of the speed fluctuation Δω _e is generated. The above-mentioned phase π / 2 corresponds to a demodulation phase θ shift described later, and has a fixed value in the first embodiment.

From the following equation (5), the speed estimator (PLL) 30 performs the proportional integral (PI) on the axis error Δθ output by the axis error computing unit 29 so that the axis error Δθ approaches zero. Generate an average estimated velocity ω _e0 . Since the fluctuation of the axis error Δθ is suppressed by the speed fluctuation Δω _e which is the output of the speed fluctuation generator 31, the average estimated speed ω _e0 in which the influence of the fluctuation of the axis error Δθ is suppressed is calculated by the following equation (5) Can be generated by

Where K _p is a proportional gain of the velocity estimator (PLL) 30 and K _i is an integral gain of the velocity estimator (PLL) 30. When the proportional gain K _p and the integral gain K _i are defined as positive values, the sign of the axis error Δθ is made minus, as in the above equation (5). This is because the rotational angle position (estimated rotational angle position) θ _{dc of} the control axis (dc-dq axis) estimated when the axis error Δθ is positive is ahead of the actual rotational angle position θ _dq of the rotational axis (dq axis) If you are the so lowered the average estimated speed omega _e0, when the axis error Δθ is negative, i.e. the control axis is behind the dq axis in order that the increased average estimated speed omega _e0.

The adder 32 adds the correction of the average estimated speed ω _e0 which is the output of the speed estimator (PLL) 30 and the speed fluctuation Δω _e which is the output of the speed fluctuation generator 31, as shown in the following equation (6) The estimated electrical angle estimation angular velocity ω _e is generated.

The position estimator 33 integrates the corrected estimated electrical angle velocity ω _e output from the adder 32 from the following equation (7) to estimate the electrical angle phase θ _e indicating the rotor position. As the estimated electric angle estimated angular velocity ω _e after correction is corrected for the fluctuation component of the electric angle estimated angular velocity ω _e , an accurate rotor position (electric angle phase θ _e ) in which the dq axis coincides with the control axis is estimated. be able to.

Further, the position estimator 33 calculates the mechanical angle phase θ _m of the motor 10 by dividing the electric angle estimated angular velocity ω _e after correction by the pole pair number Pn of the motor 10 and integrating the electric angle estimated angular velocity ω _e after the correction Do.

  According to the first embodiment described above, when a three-phase motor having periodical load torque fluctuation is driven by position sensorless vector control, in the prior art, the axial error Δθ output by the axial error calculator 29 is cyclically generated. Although a fluctuation occurs, an average velocity and a velocity fluctuation are generated from this axis error Δθ, and the estimated angular velocity and the actual angular velocity are synchronized by feeding back an estimated angular velocity obtained by adding these, and the axis error Δθ converges to zero.

  The axis error is the difference (phase difference) between the control axis (dc-qc axis) and the real axis (dq axis), that is, the difference between the estimated rotor position and the actual rotor position (phase difference). By delaying the phase by a predetermined phase (for example, π / 2) with respect to the axial error fluctuation and generating the speed fluctuation from the relationship between the rotor and the rotational speed of the rotor, the phase is further delayed by the predetermined phase and the axial error fluctuation is Since the position fluctuation for suppression occurs in the opposite phase to the fluctuation of the axis error, the fluctuation of the axis error is corrected.

  The fluctuation amplitude of the estimated speed is generated for each load torque fluctuation cycle by multiplying the axis error fluctuation amplitude extracted by Fourier transform, for example, by a correction gain. By doing this, it becomes possible to correct the speed fluctuation amplitude for each load torque fluctuation cycle, and it is possible to reduce the steady-state error of the axis error fluctuation.

If the fluctuation component of the axis error Δθ becomes zero, the fluctuation of the velocity does not occur in the output of the velocity estimator (PLL) 30, and the average estimated velocity ω _e0 can be generated without the fluctuation of the velocity. The estimated velocity fluctuation synchronized with the actual velocity fluctuation is generated by adding the estimated velocity fluctuation component Δω _e generated as described above to the average estimated velocity ω _e0 output by the velocity estimator (PLL) 30 can do.

  The position estimator 33 can estimate the rotor position where the control axis (dc-qc axis) matches the real axis (dq axis) by integrating the estimated speed fluctuation synchronized with the actual speed fluctuation, and on the dq coordinate When converting the two-phase output voltage (d-axis voltage and q-axis voltage) into three phases, or converting the detected three-phase current into two-phase currents (d-axis current and q-axis current) on qd coordinates The conversion error at the time of switching can be suppressed, and the damping effect and control stability can be improved by torque control for suppressing periodic load torque fluctuation.

  That is, according to the first embodiment, when performing torque control of a motor for the purpose of damping the motor having periodic load torque fluctuation, the axis error becomes zero and the estimated position of the rotor and the actual position Since the phase difference between the phase of the speed fluctuation and the phase of the output torque is optimized by matching with the above, it is possible to improve the damping effect and the damping stability in the torque control.

Second Embodiment
In the first embodiment, the speed fluctuation Δω _e is generated by delaying the phase by a fixed value of π / 2 (demodulation phase θ _Shift ) with respect to the fluctuation of the axis error Δθ. This is based on the phase relationship between position variation and velocity variation. However, if the axis error Δθ itself generated by the axis error computing unit 29 also includes an error, the phase relationship between the position change and the speed change does not hold, and the demodulation phase of the speed change Δω _e with respect to the change of the axis error Δθ At a fixed value of θ _Shift of π / 2, the axis error Δθ may not converge to zero. The error of the axis error Δθ itself is considered to be due to the response performance of the axis error computing unit 29, but if the phase relationship between the axis error Δθ and the speed fluctuation Δω _e has a dependence on the speed, the axis error Δθ It is considered that the axis error Δθ can be converged to zero by making the demodulation phase θ _Shift of the velocity fluctuation Δω _e with respect to the fluctuation different according to the velocity. Therefore, in the second embodiment, the demodulation phase θ _Shift of the velocity fluctuation Δω _e is changed according to the velocity. For example, in the high speed rotation area of the motor 10, the demodulation phase θ _{Shift is set} to π / 2 or less, and in the low speed rotation area, the demodulation phase θ _Shift is set larger than π / 2.

  The motor control apparatus 100A (refer to FIG. 6) according to the following second embodiment differs from the first embodiment in the configuration and processing of the speed fluctuation demodulator in the speed fluctuation generator 31A (refer to FIG. 6). Is the same as

(Speed fluctuation generator according to Embodiment 2)
FIG. 8 is a block diagram showing an example of the speed fluctuation generator according to the second embodiment. The speed fluctuation generator 31A according to the second embodiment includes an axis error fluctuation component separator 31A-1, an axis error fluctuation integrator 31A-2, and a speed fluctuation demodulator 31A-3. The axis error fluctuation component separator 31A-1 is the same as the axis error fluctuation component separator 31-1 in the first embodiment, and the axis error fluctuation integrator 31A-2 is the axis error fluctuation integrator 31-2 in the first embodiment. It is similar.

  The speed fluctuation demodulator 31A-3 further includes a speed fluctuation amplitude calculator 31A-31, an axis error fluctuation phase calculator 31A-32, a demodulation phase calculator 31A-33, a Pn processor 31A-34, and a speed fluctuation instantaneous value calculation. Vessel 31A-35.

Based on Δθ _{sin_i} and Δθ _{cos_i} calculated by the axis error fluctuation integrator 31A-2 from the above equations (3-1) and (3-2), the velocity fluctuation amplitude calculator 31A-31 calculates the following (9 The amplitude | Δω _e | of the fundamental wave component of the velocity fluctuation Δω _e is calculated from the equation). Since Δθ _{sin — i} and Δθ _{cos — i} are values updated every mechanical angular period, the amplitude | Δω _e | of the fundamental wave component of the speed fluctuation Δω _e is also updated every mechanical angular period.

The axial error fluctuation phase calculator 31A-32 calculates the phase φ _Δθi of the axial error fluctuation component updated for each mechanical angle cycle according to the following equation (10).

The Pn processor 31A-34 multiplies the mechanical angular velocity command value ω _m ^* input to the motor control apparatus 100 by the pole pair Pn of the motor 10 to calculate the electric angular velocity command value ω _e ^*, and calculates the demodulation phase calculator 31A. Output to -33.

The demodulation phase calculator 31A-33 has demodulation phase tables 31A-33t. FIG. 9 is a view showing an example of a demodulation phase table for correcting an axis error according to the second embodiment. The demodulation phase table 31A-33t acquires the demodulation phase θ _shift that brings the axis error Δθ close to zero for each of the electric angular velocity command values ω _e ^* output from the Pn processor 31A-34 by tuning, simulation, theoretical calculation, etc. Is a table stored in association with the electric angular velocity command value ω _e ^* . In the demodulation phase tables 31A to 33t, for example, the demodulation phase θ _shift1 is stored in association with the electric angular velocity command value ω _e ^* 1. The demodulation phase calculator 31A-33 refers to the demodulation phase table 31A-33t based on the input electric angular velocity command value ω _e ^* to calculate the demodulation phase θ _shift of the velocity fluctuation Δω _e with respect to the fluctuation of the axis error Δθ Do.

The electric demodulation phase calculator 31A-33, in the demodulation phase table 31A-33t, when the electrical angular velocity command value omega _e ^* which matches the electrical angular velocity command value input omega _e ^* does not exist, that is input The demodulation phase θ _shift associated with the electric angular velocity command value ω _e ^* that is closest to the angular velocity command value ω _e ^* is acquired. Alternatively, the electrical demodulation phase calculator 31A-33, in the demodulation phase table 31A-33t, when the electrical angular velocity command value omega _e ^* which matches the electrical angular velocity command value input omega _e ^* does not exist, that is input The target demodulation phase θ _shift may be calculated by linear interpolation from the demodulation phases θ _shift associated with the two values closest to the angular velocity command value ω _e ^* .

The velocity fluctuation instantaneous value calculator 31A-35 calculates an instantaneous value of the velocity fluctuation Δω _e from the following equation (11). By this calculation processing, the demodulation phase θ _{shift of the} velocity fluctuation is reflected on the accumulation result of the axial error fluctuation by the above equations (3-1) and (3-2), and the velocity fluctuation Δω at the mechanical angle phase θ _m An instantaneous value of _e is generated. The speed fluctuation Δω _e which is an instantaneous value generated by the speed fluctuation instantaneous value calculator 31A-35 is changed to the average estimated speed ω _e0 from the equation (6) in the adder 32 as in the first embodiment. By adding Δω _e, a corrected estimated electrical angle velocity ω _e including the fluctuation component is generated. The operator between the second term “φ _Δθi ” and the third term “θ _shift ” in the sine function on the right side of the following equation (11) becomes “+” when advancing the phase, and the phase It becomes "-" when delaying.

According to the second embodiment described above, in addition to the first embodiment, considering that the demodulation phase θ _shift of the velocity fluctuation Δω _e for the axial error Δθ to converge to zero depends on the velocity, the velocity fluctuation Δω _e Since the demodulation phase is changed according to the number of rotations, the axis error Δθ can be converged to zero.

Modification of Embodiment 2
In the second embodiment, the demodulation phase calculator 31A-33 refers to the demodulation phase table 31A-33t based on the input electric angular velocity command value ω _e ^* to demodulate the velocity fluctuation Δω _e with respect to the fluctuation of the axis error Δθ. It is assumed that the phase θ _shift is acquired. However, the present invention is not limited to this, and the demodulation phase calculator 31A-33 does not have the demodulation phase table 31A-33t, and the relationship between the velocity and the demodulation phase at which the axis error becomes zero is a linear function or a quadratic function. When the approximate expression can be made by the function f (ω _m ^* ) of the mechanical angular velocity command value ω _m ^* , the demodulation phase θ _shift of the velocity fluctuation Δω _e with respect to the fluctuation of the axis error Δθ is calculated from the following equation (12) It is also good.

  About the above-mentioned embodiment and the specific name of illustration, processing, control, and information including various data and parameters, it shows only an example and can be suitably changed except a special mention. In addition, the configuration of each unit or each device in the above-described embodiment may be appropriately dispersed or integrated in view of processing load, mounting efficiency, and the like. Further, each process in the above-described embodiment may be executed by appropriately changing the process order from the process load, the mounting efficiency, and the like.

  The broader aspects of the embodiments described above are not limited to the specific details and representative embodiments represented and described above. Accordingly, various modifications may be made without departing from the general inventive concept or scope as defined by the appended claims and their equivalents.

10 Motor 11, 16, 17 Subtractor 12 Speed Controller 13, 19, 20, 32 Adder 14 Current Command Generator 15 Correction Torque Generator 18 Voltage Command Generator 21 dq / u, v, w Converter 22 PWM modulator 24, 25 current sensor 26 shunt resistor 27 3φ current calculator 28 u, v, w / dq converter 29 axis error calculator 30 speed estimator (PLL)
31, 31A Speed fluctuation generator 31-1, 31A-1 Axis error fluctuation component separator 31-2, 31A-2 Axis error fluctuation integrator 31-3, 31A-3 Speed fluctuation demodulator 31A-31 Speed fluctuation amplitude calculation 31A-32 Axis error fluctuation phase calculator 31A-33 Demodulation phase calculator 31A-33t Demodulation phase table 31A-34 Pn processor 31A-35 Speed fluctuation instantaneous value calculator 33 Position estimator 34 Decoupling controller 35 1 / Pn processor 100, 100A motor controller

Claims (3)

An axis error calculator for calculating an axis error between the motor control axis and the real axis;
A speed estimator for estimating an average estimated speed of the motor from the axis error;
A speed fluctuation generator that generates the speed fluctuation of the motor from the axis error;
A motor control device comprising: a position estimator which estimates a rotational angle position of the motor from an estimated speed obtained by adding the average estimated speed of the motor and the speed fluctuation of the motor. The speed fluctuation generator
An axial error fluctuation component separator that separates a fundamental wave component from a fluctuation component of the axial error;
An axis error fluctuation integrator that integrates the fundamental wave component separated by the axis error fluctuation component separator for each mechanical angle cycle of the motor;
A velocity fluctuation demodulator that delays the mechanical angle phase of the motor estimated by the position estimator by a predetermined amount from the fundamental wave component integrated by the axis error fluctuation integrator to generate the velocity fluctuation of the motor; The motor control device according to claim 1, further comprising: The speed fluctuation demodulator is
A velocity fluctuation amplitude calculator that calculates the magnitude of the fundamental wave component separated by the axial error fluctuation component separator;
An axial error fluctuation phase calculator that calculates the phase of the fluctuation component of the axial error updated for each mechanical angle cycle from the fundamental wave component separated by the axial error fluctuation component separator;
A motor angular velocity command value input to the motor control device is converted into an electrical angular velocity command value, and a demodulation phase of the velocity fluctuation is calculated from the electrical angular velocity command value such that a fluctuation component of the axis error approaches zero. A phase calculator,
The magnitude of the fundamental wave component calculated by the velocity fluctuation amplitude calculator, the phase of the fluctuation component of the axis error calculated by the axis error fluctuation phase calculator, and the velocity calculated by the demodulation phase calculator The motor control device according to claim 2, further comprising: a velocity fluctuation instantaneous value calculator that generates an instantaneous value of the velocity fluctuation at the mechanical angle phase of the motor from the demodulation phase of the fluctuation.

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