Motor control device

Abstract

To estimate a rotational position of a motor with high accuracy.SOLUTION: A motor control device for estimating a rotational position of a motor comprises: a high-frequency signal application part that applies a high-frequency signal for estimating the rotational position; an induced voltage estimation device that estimates an expansion induced voltage excited by overlapping the high-frequency signal; and a position estimation device that estimates the rotational position of the motor on the basis of the expansion induced voltage. The induced voltage estimation device includes: a high-speed expansion induced voltage estimation observer that estimates a first expansion induced voltage at a high-speed rotation of the motor; a low-speed expansion induced voltage estimation observer that estimates a second expansion induced voltage at a low-speed rotation of the motor; and a voltage synthesis part that synthesizes the first and second expansion induced voltages, and outputs the expansion induced voltage. The high-speed expansion induced voltage estimation observer contains a time constant variable filter that adjusts a phase of the first expansion induced voltage.SELECTED DRAWING: Figure 2

Description

[Technical field]

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

[0002] Conventionally, position sensorless control of a synchronous motor (hereinafter, motor) is known (for example, see Non-Patent Document 1). In the position sensorless control of a motor, the rotational position of the motor is estimated from the extended electromotive force (EEMF) without using a position sensor. In this position sensorless control, the extended electromotive force (EEMF) excited in proportion to the rotational speed of the motor is used as the ω ) and the extended induced voltage (EEMF) excited by superimposing a high-frequency signal h Specifically, in the position sensorless control, the EEMF is used in the medium to high speed range of the motor. ω By using EEMF, the motor stops at low speeds. ω The shortfall is made up by EEMF h By supplementing this with the rotational position, the rotational position is estimated over the entire speed range. [Prior art documents] [Non-patent literature]

[0003] [Non-Patent Document 1] Takumi Futamura and Shinji Michiki, "Full-Speed ​​Position Sensorless Control of Permanent Magnet Synchronous Motors Using Signal Superposition and Speed-Excited Extended Induced Voltage", IEEJ Transactions on Electrical Engineering, Japan, IEEJ, 2020, Vol. 140, No. 8, pp. 589-596 Summary of the Invention [Problem to be solved by the invention]

[0004] In the position sensorless control of the motor in Non-Patent Document 1, a high frequency signal is applied to estimate the position of the motor when it is stopped and at low speed. On the other hand, in the position sensorless control, position estimation is performed from the extended electromotive force caused by the speed in the medium and high speed ranges of the motor, so a high frequency signal is not necessary, and the application of a high frequency signal becomes a disturbance that deteriorates the accuracy of the position estimation. Furthermore, in the position sensorless control, a low pass filter (LPF) and a band pass filter (BPF) are used to extract the signals required for position estimation when the motor is stopped and at low speed. As a result, the EEMF obtained through the LPF and BPF is h (e2 ^ ) and EEMF ω (e1 ^ ) may cause a phase shift in the estimation accuracy of the motor's rotational position.

[0005] In view of the above, an object of the present disclosure is to provide a motor control device that can accurately estimate the rotational position of a motor. [Means for solving the problem]

[0006] The motor control device disclosed herein is a motor control device that estimates a rotational position of a motor, and includes a high-frequency signal application unit that applies a high-frequency signal for estimating the rotational position, an induced voltage estimator that estimates an extended induced voltage excited by superimposing the high-frequency signal, and a position estimator that estimates the rotational position of the motor based on the extended induced voltage, wherein the induced voltage estimator has a high-speed extended induced voltage estimation observer that estimates a first extended induced voltage when the motor is rotating at high speed, a low-speed extended induced voltage estimation observer that estimates a second extended induced voltage when the motor is rotating at low speed, and a voltage synthesis unit that synthesizes the first extended induced voltage and the second extended induced voltage to output the extended induced voltage, and the high-speed extended induced voltage estimation observer includes a time constant variable filter that adjusts the phase of the first extended induced voltage. Effect of the Invention

[0007] According to the present disclosure, the rotational position of the motor can be estimated with high accuracy. [Brief description of the drawings]

[0008] [Figure 1] FIG. 1 is a diagram relating to a motor control device according to the present embodiment. [Diagram 2] FIG. 2 is a diagram relating to an induced voltage estimator of the motor control device according to this embodiment. [Diagram 3] FIG. 3 is a phase diagram relating to the frequency characteristics of the low-pass filter of the elimination filter. [Figure 4] FIG. 4 is a Bode plot of the gain characteristic of the observer. [Diagram 5] FIG. 5 is an explanatory diagram of the extended induced voltage before and after noise is removed. [Figure 6] FIG. 6 is a graph comparing the deviation between the command value and the actual measured value regarding the rotation speed of the motor in this embodiment with that in the conventional method. [Figure 7] FIG. 7 is a graph comparing the estimation error of the rotational position of the motor in this embodiment with the conventional method. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0009] Hereinafter, the embodiments of the present disclosure will be described in detail with reference to the drawings. Note that the disclosure is not limited to these embodiments. In addition, the components in the following embodiments include those that are easily replaceable by those skilled in the art, or those that are substantially the same. Furthermore, the components described below can be appropriately combined, and when there are multiple embodiments, each embodiment can be combined.

[0010] [Present embodiment] The motor control device 10 according to this embodiment is a device that controls the rotation of a motor 5, and is, for example, a vector control device. The motor 5 is, for example, a three-phase motor, and the motor control device 10 controls the motor 5 by converting a two-phase voltage of the d-axis and q-axis into a three-phase voltage of U-phase, V-phase, and W-phase. The motor control device 10 will be described with reference to FIG. 1.

[0011] (Motor control device) Fig. 1 is a diagram relating to a motor control device according to this embodiment. As shown in Fig. 1, a motor control device 10 includes a rotation speed control unit 21, a torque control unit 22, a high-frequency signal application unit 23, a current control unit 24, two-phase / three-phase conversion units 25 and 26, an induced voltage estimator 27, a position estimator 28, and a rotation speed estimator 29.

[0012] The rotation speed control unit 21 controls the rotation speed of the motor 5, and a speed command value ω * and the estimated rotation speed ω of the motor 5. ^ (In addition," ^ " is a symbol added above the text in the figure) and the estimated speed value ω of the rotation speed of the motor 5 are input. ^ is input from a rotation speed estimator 29, which will be described later. The rotation speed control unit 21 calculates the input speed estimate value ω ^ is the speed command value ω * The torque command value T of the rotation torque of the motor 5 is set to * Output.

[0013] The torque control unit 22 controls the rotation torque of the motor 5, and receives a torque command value T * The torque control unit 22 receives the input torque command value T * Based on this, the current command value Idq applied to the motor 5 is * Output.

[0014] The high-frequency signal application unit 23 applies a high-frequency voltage that becomes a high-frequency signal to the current control unit 24. The high-frequency signal is a voltage that is applied in order to estimate the rotational position of the motor 5.

[0015] The current control unit 24 controls the current input to the motor 5, and receives a current command value Idq from the torque control unit 22. * is input. Current command value Idq * are the current command values ​​for the d-axis and q-axis. The current control unit 24 calculates the input current command value Idq* Based on this, the current control unit 24 controls the current and voltage to be input to the two-phase / three-phase conversion unit 25. Furthermore, based on the current output from a two-phase / three-phase conversion unit 26 described later, the current control unit 24 executes decoupling control to suppress current oscillation due to interference between the d- and q-axes.

[0016] The two-phase / three-phase conversion unit 25 converts the current and voltage in the dq orthogonal two-axis rotating coordinate system input from the current control unit 24 into a current (Iuvw) and voltage in a UVW three-phase stationary coordinate system, and outputs them to the motor 5. The two-phase / three-phase conversion unit 26 converts the current (Iuvw) and voltage in the UVW three-phase stationary coordinate system output from the two-phase / three-phase conversion unit 25 into a current and voltage in a dq orthogonal two-axis rotating coordinate system, and inputs them to the current control unit 24. The two-phase / three-phase conversion units 25 and 26 also receive the rotational position θ of the motor 5 estimated by a position estimator 28, which will be described later. ^ is input, and the rotation position θ ^ The conversion process is performed based on the

[0017] The induced voltage estimator 27 estimates the extended induced voltage e ^ Specifically, the induced voltage estimator 27 estimates the extended induced voltage e2 excited by the high-frequency signal applied by the high-frequency signal application unit 23. ^ and the extended induced voltage e1 excited in proportion to the motor rotation speed ^ The extended induced voltage e by superposing ^ It is estimated that.

[0018] Fig. 2 is a diagram relating to the induced voltage estimator of the motor control device according to this embodiment. As shown in Fig. 1 and Fig. 2, the induced voltage estimator 27 has a high-speed extended induced voltage estimation observer 31, a low-speed extended induced voltage estimation observer 32, and a voltage synthesis unit 33. The high-speed extended induced voltage estimation observer 31 and the low-speed extended induced voltage estimation observer 32 each include a current Iαβ(i) and a voltage Vαβ in a two-phase stationary coordinate system. * (v * ) is entered.

[0019] The high-speed extended induced voltage estimation observer 31 estimates the first extended induced voltage e1 ^ The high-speed extended induced voltage estimation observer 31 estimates the input current i and voltage v * Based on the first extended induced voltage e1 ^ The high-speed extended induced voltage estimating observer 31 includes a time constant variable filter 35, which estimates the first extended induced voltage e1 ^ The time constant variable filter 35 is, for example, a low-pass filter.

[0020] The low-speed extended induced voltage estimation observer 32 estimates the second extended induced voltage e2 ^ The low-speed extended induced voltage estimation observer 32 estimates the input current i and voltage v * Based on the second extended induced voltage e2 ^ The extended induced voltage estimation observer for low speed 32 also includes a rejection filter 36, which is a filter that extracts signals necessary for position estimation. The rejection filter 36 is, for example, a low-pass filter and a band-pass filter.

[0021] Here, the low-pass filter of the elimination filter 36 will be described with reference to Fig. 3. Fig. 3 is a phase diagram relating to the frequency characteristics of the low-pass filter of the elimination filter. In Fig. 3, the vertical axis represents phase, and the horizontal axis represents frequency. As shown in Fig. 3, the low-pass filter of the elimination filter 36 reduces the second extended induced voltage e2 as the rotation speed of the motor increases and the fundamental frequency of the extended induced voltage increases. ^ The frequency characteristic is such that the phase delay of

[0022] For this reason, the time constant variable filter 35 reduces the second extended induced voltage e2 by the low-pass filter of the removal filter 36 according to the rotation speed of the motor 5. ^ The first extended induced voltage e1 is set to match the phase lag of ^The frequency characteristic adjusts the phase of the

[0023] Here, the high-speed extended induced voltage estimation observer 31 and the low-speed extended induced voltage estimation observer 32 use a minimum-order observer. Fig. 4 is a Bode diagram relating to the gain characteristics of the observers. In Fig. 4, the vertical axis represents the observer gain, and the horizontal axis represents the frequency. In Fig. 4, the same-order line represents the gain characteristics of a same-order observer that estimates the extended induced voltage from the entire state of the motor 5, and the minimum-order line represents the gain characteristics of a minimum-order observer that estimates the extended induced voltage from a portion of the state of the motor 5 and has a lower order than the same-order.

[0024] As shown in Fig. 4, the minimum order observer has a flat gain characteristic at high frequencies. Therefore, at high frequencies, the control system is likely to become unstable due to disturbances caused by high-frequency signals. However, by providing the time constant variable filter 35, the second extended induced voltage e2 due to the low-pass filter of the elimination filter 36 can be reduced. ^ FIG. 5 is an explanatory diagram of the state before and after noise removal of the extended induced voltage. As shown in FIG. 5, by providing a time constant variable filter 35 in the high-speed extended induced voltage estimation observer 31, the first extended induced voltage e1 ^ The control system is stabilized by removing high frequency components that become noise in the high frequency signal.

[0025] The voltage synthesis unit 33 synthesizes the first extended induced voltage e1 output from the high-speed extended induced voltage estimation observer 31. ^ and the second extended induced voltage e2 output from the low-speed extended induced voltage estimation observer 32. ^ The combined extended induced voltage e ^ The voltage synthesis unit 33 uses a weighting function according to the rotation of the motor 5 to output the first extended induced voltage e1 ^ and the second extended induced voltage e2 ^ It is a combination of the above.

[0026] The position estimator 28 receives the extended induced voltage e ^ The position estimator 28 estimates the extended induced voltage e ^ Based on this, the rotational position θ of the motor 5 ^ It is estimated that.

[0027] The rotation speed estimator 29 receives the rotation position θ of the motor 5 from the position estimator 28. ^ The rotational speed estimator 29 receives the rotational position θ ^ That is, the rotational position θ of the motor 5 ^ Calculate the differential value of the rotation speed ω ^ The rotation speed estimator 29 estimates the rotation speed ω ^ is output to the rotation speed control unit 21.

[0028] Next, a comparison between the motor control device 10 of this embodiment and a conventional motor control device will be described with reference to Figs. 6 and 7. Fig. 6 is a graph comparing the deviation between the command value and the actual measured value regarding the rotation speed of the motor, between this embodiment and the conventional one. Fig. 7 is a graph comparing the estimation error of the rotation position of the motor, between this embodiment and the conventional one. Note that the conventional motor control device has a configuration in which the time constant variable filter 35 is omitted from the motor control device 10 of this embodiment, and the first extended induced voltage e1 ^ and the second extended induced voltage e2 ^ The phase shifts between the two signals are not aligned.

[0029] As shown in FIG. 6, the deviation between the command value and the actual measured value of the motor rotation speed tends to become large at the timing of the arrow when the motor 5 changes from low speed to high speed. At the timing of the arrow, the deviation of this embodiment shown in the upper diagram is smaller than the conventional deviation shown in the lower diagram. In other words, it was confirmed that this embodiment can accurately estimate the motor rotation speed, and therefore can reduce the deviation between the actual measured value and the command value of the motor rotation speed compared to the conventional case. In the example shown in FIG. 6, the deviation ΔN of the rotation speed of this embodiment is 20 rpm, which is 0.25% of the speed fluctuation, and the deviation ΔN of the conventional rotation speed is 130 rpm, which is 1.6% of the speed fluctuation.

[0030] Also, as shown in FIG. 7, the estimation error of the motor's rotational position tends to become large at the timing of the arrow when the motor 5 transitions from low speed to high speed, as in FIG. 6. At the timing of the arrow, the estimation error of this embodiment shown in the upper diagram is smaller than the conventional estimation error shown in the lower diagram. In other words, it was confirmed that this embodiment can estimate the motor's rotational position with higher accuracy than the conventional method. In the example shown in FIG. 7, the estimation error Δθpp of the rotational position of this embodiment is 1.5 deg, while the estimation error Δθpp of the conventional rotational position is 4.2 deg.

[0031] As described above, the motor control device 10 according to the present embodiment can be understood, for example, as follows.

[0032] A motor control device 10 according to a first aspect of the present invention is a motor control device 10 that estimates a rotational position of a motor 5, the motor control device 10 including a high-frequency signal application unit (high-frequency signal application unit 23) that applies a high-frequency signal for estimating the rotational position, and an extended induced voltage e excited by superimposing the high-frequency signal. ^ and an induced voltage estimator 27 for estimating the extended induced voltage e ^ and a position estimator 28 for estimating the rotational position of the motor based on a first extended induced voltage e1 ^and a high-speed extended induced voltage estimating observer 31 that estimates the second extended induced voltage e2 during low-speed rotation of the motor 5. ^ and a low-speed extended induced voltage estimating observer 32 for estimating the first extended induced voltage e1 ^ and the second extended induced voltage e2 ^ The extended induced voltage e ^ and a voltage synthesis unit 33 that outputs the first extended induced voltage e1. ^ The variable time constant filter 35 adjusts the phase of the

[0033] According to this configuration, the second extended induced voltage e2 ^ Even if a phase delay occurs in the first extended induced voltage e1, the time constant variable filter 35 ^ By adjusting the phase of the first extended induced voltage e1 ^ and the second extended induced voltage e2 ^ This allows the rotational position of the motor 5 to be estimated with high accuracy.

[0034] As a second aspect, in the motor control device 10 according to the first aspect, the low-speed extended induced voltage estimation observer 32 includes a removal filter 36 that removes high-frequency components of the high-frequency signal, and the removal filter 36 reduces the second extended induced voltage e2 ^ The time constant variable filter 35 increases the phase delay of the second extended induced voltage e2 by the removal filter 36 in accordance with the rotation speed of the motor 5. ^ The first extended induced voltage e1 ^ Adjust the phase of the signal.

[0035] According to this configuration, the time constant variable filter 35 can be made to correspond to the frequency characteristics of the elimination filter 36, so that the first extended induced voltage e1 ^ and the second extended induced voltage e2 ^ The phase of the signal can be suitably matched to that of the signal.

[0036] As a third aspect, in the motor control device 10 according to the first or second aspect, the time constant variable filter 35 has a function of removing noise from the high frequency signal.

[0037] According to this configuration, by providing the time constant variable filter 35, the first extended induced voltage e1 ^ By removing the high frequency components that become noise in the high frequency signal from the control system, it is possible to stabilize the control system, and therefore to suppress instability of the control caused by changes in the rotation speed of the motor 5. [Explanation of symbols]

[0038] 5 Motor 10 Motor control device 21 Rotational speed control section 22 Torque control section 23 High frequency signal application section 24 Current control section 25, 26 Two-phase / three-phase converter 27 Back EMF Estimator 28 Position Estimator 29 Rotational Speed ​​Estimator 31 High-speed extended induced voltage estimation observer 32 Extended induced voltage estimation observer for low speed 33 Voltage synthesis section 35 Variable time constant filter 36 Removal Filter

Claims

1. 2. A motor control device that estimates a rotational position of a motor, a high frequency signal applying unit that applies a high frequency signal for estimating the rotational position; an induced voltage estimator that estimates an extended induced voltage excited by superimposing the high frequency signal; a position estimator that estimates the rotational position of the motor based on the extended induced voltage, The induced voltage estimator is a high speed extended induced voltage estimating observer that estimates a first extended induced voltage during high speed rotation of the motor; a low speed extended induced voltage estimating observer that estimates a second extended induced voltage during low speed rotation of the motor; a voltage synthesis unit that synthesizes the first extended induced voltage and the second extended induced voltage to output the extended induced voltage, The motor control device, wherein the high speed extended induced voltage estimation observer includes a time constant variable filter that adjusts the phase of the first extended induced voltage.

2. the low-speed extended induced voltage estimation observer includes a removal filter that removes high-frequency components of the high-frequency signal, the removal filter increases a phase lag of the second extended induced voltage as the rotation speed of the motor increases; 2. The motor control device according to claim 1, wherein the time constant variable filter adjusts a phase of the first extended induced voltage to match a phase delay of the second extended induced voltage caused by the removal filter in accordance with a rotation speed of the motor.

3. 2. The motor control device according to claim 1, wherein the variable time constant filter has a function of removing noise from the high frequency signal.

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