JP4766530B2 - Motor controller with magnetic flux angle correction function - Google Patents

Description

  The present invention relates to a motor control device that controls a motor, and more particularly, to a motor control device having a function of correcting a magnetic flux angle of a permanent magnet synchronous motor.

  In general, in order to control a permanent magnet synchronous motor (hereinafter simply referred to as “motor”), it is extremely important to accurately grasp the relative positional relationship between the stator and the rotor (hereinafter referred to as “magnetic flux angle”). is important. For this reason, the motor control device that controls the motor is provided with a pair of magnetoelectric transducers composed of Hall sensors and the like arranged with an electrical angle shifted by 90 °, and a sine wave signal and a cosine wave signal output therefrom. Based on this, the magnetic flux angle is grasped.

  However, since the magnetic flux angle obtained by the magnetoelectric converter includes some errors due to processing errors of parts constituting the motor or assembly errors between parts, the motor cannot be controlled with high accuracy only by this information. .

Therefore, for example, in the motor control device described in Patent Document 1, the d-axis current, the q-axis current, and the d-axis voltage of a motor operating in an arbitrary state are measured, and the magnetic flux angle error is estimated based on these. ing. And the true magnetic flux angle is calculated | required by correct | amending the magnetic flux angle obtained from a magnetoelectric converter with the estimated magnetic flux angle error.
JP 2005-269761 A

  However, with this method, the motor cannot be started when the error is large. Therefore, in the conventional motor control device, it is necessary to manually adjust the magnetic flux angle to such an extent that it can be rotated in advance, which is very troublesome.

  The present invention has been made in view of the above circumstances, and the problem is that a motor control device that does not require manual adjustment of the magnetic flux angle in advance and can correct the magnetic flux angle error with high accuracy. Is to provide.

  In order to solve the above problems, a motor control device according to the present invention is a motor control device that controls a motor by vector control based on a d-axis and q-axis command current, and the d-axis and q-axis of the motor Based on the command current and the d-axis and q-axis currents, the first magnetic flux of the motor such that the d-axis current is equal to the d-axis command current and the q-axis current is equal to the q-axis command current. A sine wave signal and a cosine wave signal that are provided in or near the motor and that output the angular and first magnetic flux angular velocities and correspond to the relative positional relationship between the stator and the rotor of the motor. The d-axis current becomes equal to the d-axis command current, and the q-axis current becomes equal to the q-axis command current based on a pair of magnetoelectric converters that output and the sine wave signal and cosine wave signal Such a second of the motor A second detector for outputting a bundle angle and a second magnetic flux angular velocity, and receiving a command from the outside, the motor made unloaded based on the first magnetic flux angle and the first magnetic flux angular velocity is made constant by vector control. A mode control unit that switches between a correction mode to be operated and a normal mode in which the motor is normally operated by vector control based on the second magnetic flux angle and the second magnetic flux angular velocity; and in the correction mode, A correction angle measuring unit that measures a phase shift amount of the second magnetic flux angle and outputs the shift amount as a correction angle; and a storage unit that stores the correction angle, and the second detection unit in the normal mode. The second magnetic flux angle output from is corrected by the correction angle.

  Preferably, the motor control device includes a correction value measuring unit that measures amplitudes and offsets of the sine wave signal and the cosine wave signal in the correction mode and outputs the amplitudes and offsets as correction values, and the storage unit Further stores the correction value, and the second detection unit corrects the sine wave signal and the cosine wave signal with the correction value, and based on the corrected sine wave signal and cosine wave signal, The second magnetic flux angle and the second magnetic flux angular velocity of the motor are output.

  More preferably, in the motor control device, the correction angle and the correction value are average values during the constant speed operation of the motor.

  In order to solve the above-described problem, a forklift according to the present invention includes any one of the motor control devices described above, and the forklift controls the EPS motor with the motor control device, and the q-axis command current is supplied to the steering. The d-axis command current is constant according to the applied torque, and the d-axis command current is constant.

  According to the present invention, there is no need to manually adjust the magnetic flux angle in advance, and it is possible to provide a motor control device that can correct the magnetic flux angle error with high accuracy.

  Hereinafter, a preferred embodiment of a motor control device according to the present invention will be described with reference to the accompanying drawings.

[Function of each block]
FIG. 1 is a block diagram of a motor control device 1 according to the present invention. The motor control device 1 according to the present embodiment controls a 6-pole EPS motor (motor 21) that assists in changing the steering wheel angle. The motor 21 is vector-controlled so that it is generated. As is well known, the relative positional relationship between the stator and the rotor in the motor 21 can be expressed using a “mechanical angle” and an “electrical angle”. Unless otherwise specified, the rotational position is expressed by “electrical angle (= magnetic flux angle)”.

In the block diagram of FIG. 1, the speed control unit 5 is obtained by converting the angular velocity command ω _r output from the mode control unit 2 and the magnetic flux angular velocity ω ₃ output from the speed / angle switching unit 13 into a mechanical angle. A deviation Δω with respect to ω ₄ is proportionally / integrated to output a first q-axis current command i _q1 . The torque sensor 4 detects the torque applied to the steering 3 and outputs a second q-axis current command i _q2 proportional to the torque. In addition, the current switching unit 6 outputs either the first q-axis current command i _q1 or the second q-axis current command i _q2 in accordance with the first mode switching signal C ₁ (details will be described later). Output as i _q .

The current-voltage conversion unit 7 refers to the magnetic flux angle θ ₃ and the magnetic flux angular velocity ω _{3 so} that the q-axis current I _q is equal to the q-axis current command i _q and the d-axis current I _d is changed to the d-axis current command i. A d-axis voltage command V _d and a q-axis voltage command V _q that are equal to _d (“0” in this embodiment) are output.

続いて、二相−三相座標変換部８は、上記変数Ｖ_a、Ｖ_bを用いた次式によってｕ、ｖ、ｗ各相の電圧Ｖ_u、Ｖ_v、Ｖ_wを求め、該電圧によりモータ２１を駆動する。

Based on the d-axis voltage command V _d and the q-axis voltage command V _q , the two-phase to three-phase coordinate conversion unit 8 first obtains variables V _a and V _b by the following equations.

Subsequently, the two-phase to three-phase coordinate conversion unit 8 obtains voltages V _u , V _v , and V _w of each phase u, v, and w by the following equation using the variables V _a and V _b, and uses the voltages. The motor 21 is driven.

As shown in FIG. 1, each phase line connecting the two-phase to three-phase coordinate conversion unit 8 and the motor 21 is provided with a current sensor. The actual currents I _u , I _v , and I _w of the u, v, and w phases that flow toward 21 can be detected.

続いて、三相−二相座標変換部９は、上記変数Ｉ_a、Ｉ_bを用いた次式によってｄ軸電流Ｉ_d及びｑ軸電流Ｉ_qを求める。

Based on the detected currents I _u , I _v , and I _w of each phase, the three-phase to two-phase coordinate conversion unit 9 first obtains variables I _a and I _b by the following equations.

Subsequently, the three-phase to two-phase coordinate conversion unit 9 obtains the d-axis current I _d and the q-axis current I _q by the following equations using the variables I _a and I _b .

ここで、定数Ｒ_aはモータ２１の相抵抗、定数Ｌ_qはｑ軸インダクタンスである。 Based on the d-axis voltage V _d , the q-axis voltage V _q , the d-axis current I _d , the q-axis current I _q and the first magnetic flux angular velocity ω ₁ described later, the error angle detection unit 10 calculates the error angle ΔD by the following equation. Ask.

Here, the constant _Ra is the phase resistance of the motor 21, and the constant _Lq is the q-axis inductance.

The proportional / integral control unit 11 obtains the first magnetic flux angular velocity ω ₁ such that the error angle ΔD becomes zero. The angle conversion section 12 integrates the first magnetic flux angular velocity omega _1, obtaining the first magnetic flux angle theta ₁ in the range of 0 to 360 °. The first magnetic flux angular velocity ω ₁ and the first magnetic flux angle θ ₁ are output toward the speed / angle switching unit 13. The operation of the speed / angle switching unit 13 will be described later. In this specification, the error angle detection unit 10, the proportional / integral control unit 11, and the angle conversion unit 12 are collectively referred to as a first detection unit 30.

As shown in FIG. 1, a pair of magnetoelectric converters 15 including Hall sensors and the like arranged with an electrical angle shifted by 90 ° are provided in or near the motor 21. The magnetoelectric converter 15 outputs a cosine wave signal HS ₁ (= cos θ _b ) and a sine wave signal HS ₂ (= sin θ _b ) having an electrical phase difference of 90 °. When the motor 21 is rotating at a constant speed, the magnetoelectric converter 15 outputs, for example, a cosine wave signal HS ₁ and a sine wave signal HS ₂ as shown in FIG.

Due to processing errors of parts constituting the motor or assembly errors between parts, a deviation occurs in amplitude and / or offset between the cosine wave signal HS ₁ and the sine wave signal HS ₂ . For example, in the example shown in FIG. 2A, the amplitude and offset of the cosine wave signal HS ₁ are V _a1 and V _o1 , respectively, whereas the amplitude and offset of the sine wave signal HS ₂ are V _a2 (< V _a1 ), V _o2 (<V _o1 ). Therefore, in this state, it is impossible to obtain accurate flux angle theta _b.

Therefore, in the motor control device 1 according to the present invention, the amplitude and offset of the cosine wave signal HS ₁ and the sine wave signal HS ₂ are measured in advance and stored as correction values (see FIG. 2A). Then, the magnetic flux angle θ _b is obtained using the cosine wave signal HS ₁ ′ and the sine wave signal HS ₂ ′ (see FIG. 2B) after being corrected with this correction value (see FIG. 2C).

上式を用いた補正によれば、結局、図２（Ｂ）に示す余弦波信号ＨＳ₁’及び正弦波信号ＨＳ₂’を得ることができる。そして、角度検出部１６は、この余弦波信号ＨＳ₁’及び正弦波信号ＨＳ₂’に基づいて、次式により磁束角θ_bを求める（図２（Ｃ）参照）。

Specifically, the correction value measuring unit 18 measures the amplitude V _a1 and the offset V _{o1 of} the cosine wave signal HS ₁ and the amplitude V _a2 and the offset V _{o2 of the} sine wave signal HS ₂ , and stores them at a predetermined timing. 20. The angle detection unit 16 corrects the cosine wave signal HS ₁ and the sine wave signal HS ₂ using each correction value stored in the storage unit 20. Correction is performed by the following equation.

According to the correction using the above equation, the cosine wave signal HS ₁ ′ and the sine wave signal HS ₂ ′ shown in FIG. Then, the angle detection unit 16, based on this cosine wave signal HS ₁ 'and a sine wave signal HS _2', (see FIG. 2 (C)) for obtaining the magnetic flux angle theta _b by the following equation.

Note that the angle detection unit 16 also performs correction to set the magnetic flux angle θ _b to the second magnetic flux angle θ ₂ based on the correction angle θ _a measured in advance, which will be described later.

The speed conversion unit 17 differentiates the second magnetic flux angle θ ₂ output from the angle detection unit 16 to obtain the second magnetic flux angular velocity ω ₂ . The second magnetic flux angular velocity ω ₂ and the second magnetic flux angle θ ₂ are output toward the speed / angle switching unit 13.

補正角θ_aは、所定のタイミングで記憶部２０に格納される。 The correction angle measurement unit 19 receives the first magnetic flux angle θ ₁ and the second magnetic flux angle θ ₂ . Then, the correction angle measurement unit 19 measures the amount of phase shift of the second magnetic flux angle θ ₂ with respect to the first magnetic flux angle θ _{1 and} outputs this as the correction angle θ _a . A first magnetic flux angle theta ₁ and the second magnetic flux angle theta ₂ of the phase relationship between the correction angle theta _a are as follows, as shown in FIG. 3, the second to the first magnetic flux angle theta ₁ When the phase of the magnetic flux angle θ ₂ is delayed, the correction angle θ _a is a positive value.

The correction angle θ _a is stored in the storage unit 20 at a predetermined timing.

この補正によれば、第１磁束角θ₁と同位相の第２磁束角θ₂を得ることができる。なお、本明細書では、角度検出部１６及び速度変換部１７を第２検出部３１と総称する。 The above-described correction of the magnetic flux angle θ _b in the angle detection unit 16 is performed using the correction angle θ _{a according} to the following equation.

According to this correction, the second magnetic flux angle θ ₂ having the same phase as the first magnetic flux angle θ ₁ can be obtained. In the present specification, the angle detection unit 16 and the speed conversion unit 17 are collectively referred to as a second detection unit 31.

  Next, two modes of the motor control device 1 according to the present invention, that is, “correction mode” and “normal mode” will be described.

[Correction mode]
And the correction mode uses only the blocks shown in FIG. 4, to measure the correction value regarding the amplitude or the like of the correction angle theta _a and the cosine wave signal HS ₁ and sine wave signal HS ₂ is rotated at a constant speed motor 21, storage The mode stored in the unit 20 is referred to.

As shown in FIG. 5, when the motor 21 can be unloaded at the time of factory shipment or when the motor 21 is replaced, when the operator turns on the mode switch, the correction mode is set, and the mode control unit 2 performs the first mode command. The signal C ₁ is changed to “H”. When the first mode command signal C ₁ is “H”, the speed / angle switching unit 13 selects the first magnetic flux angle θ ₁ and the first magnetic flux angular speed ω ₁ , which are set as the magnetic flux angle θ ₃ and the magnetic flux angular speed ω _3. Output. The current switching unit 6 selects the first q-axis current command i _q1 from the speed control unit 5 and outputs this as the q-axis current command i _q . That is, in the correction mode, the operation of the motor 21 is instructed not by the steering 3 but by the angular velocity command ω _r from the mode control unit 2.

When the operator turns on the motor drive switch after entering the correction mode, the mode control unit 2 gradually increases the angular velocity command ω _r over time T ₁ as shown in FIG. At this time, the current-voltage conversion unit 7 refers to the magnetic flux angle θ ₃ (= first magnetic flux angle θ ₁ ) and magnetic flux angular velocity ω ₃ (= first magnetic flux angular velocity ω ₁ ) output from the speed / angle switching unit 13. while, q-axis current I _q is equal to the q-axis current command i _q, and d-axis current I _d is the d-axis current command i _d equal such q-axis voltage command V _q and the d-axis voltage command V _d And the motor 21 is vector-controlled.

The reason why the motor drive switch is provided separately from the mode change switch is to prevent the operator from updating the correction value stored in the storage unit 20 by mistake. If such concern is not to omit the motor drive switch, after a certain period of time after being set to the correction mode angular velocity instruction omega _r may also be begins to increase.

When the time T ₁ elapses and the motor 21 enters the constant speed operation state, the mode control unit 2 changes the second mode command signal C ₂ to “H”. Then, using this as a trigger, the correction value measuring unit 18 and the correction angle measuring unit 19 start operating.

As described above, the correction value measurement unit 18 measures the amplitude V _a1 and offset V _{o1 of the} cosine wave signal HS ₁ output from the magnetoelectric converter 15 and the amplitude V _a2 and offset V _o2 of the limit wave signal HS ₂ . The correction angle measurement unit 19 measures the amount of phase shift of the second magnetic flux angle θ ₂ with respect to the first magnetic flux angle θ _{1 and} outputs this as the correction angle θ _a .

Since the first detection unit 30 can detect the true magnetic flux angle while the motor 21 is operating at no load and at a constant speed, the first magnetic flux angle θ ₁ is the true magnetic flux angle. On the other hand, the second magnetic flux angle θ ₂ before correct correction includes an error. The correction angle θ _a output from the correction angle measurement unit 19 is the phase shift amount of the second magnetic flux angle θ ₂ with respect to the first magnetic flux angle θ ₁ as described above. Therefore, according to the correction angle theta _a, it can be corrected to cancel the second flux angle theta ₂ of the phase error. From the viewpoint of improving the correction accuracy, the offsets V _o1 , V _o2 , amplitudes V _a1 , V _a2, and correction angle θ _a are determined while the motor 21 is rotating at a constant speed (during time T _{2 in} FIG. 5). ) Is preferable.

When the time T ₂ elapses after the second mode command signal C ₂ becomes “H”, the mode control unit 2 starts to gradually decrease the angular velocity command ω _r and sets the second mode command signal C ₂ to “L”. Change to As a result, the operations of the correction value measuring unit 18 and the correction angle measuring unit 19 are stopped. The correction value measurement unit 18 and the correction angle measurement unit 19 continue to output the correction value and the like when the second mode command signal C ₂ becomes “L” even after the operation is stopped.

Thereafter, when the time T ₃ elapses, the mode control unit 2 sets the third mode command signal C ₃ to “H”, and as a trigger, correction values and corrections regarding the offsets V _o1 and V _o2 and the amplitudes V _a1 and V _a2. The angle θ _a is stored in the storage unit 20. When the previous correction value or the like is already stored in the storage unit 20, it is updated to the latest one. Then, the latest correction value and the correction angle θ _a can be referred to by the angle detector 16.

[Normal mode]
In the normal mode, only the block shown in FIG. 6 is used, and the motor 21 is normally operated in accordance with the operation of the steering wheel 3 while performing correction using the correction angle θ _a and the correction value stored in the storage unit 20. This is the mode to be used. That is, since the normal mode is based on the assumption that correction values and the like are stored in the storage unit 20, it is necessary to operate at least once in the correction mode before the normal mode.

In this mode, the angle detector 16 corrects the cosine wave signal HS ₁ and the sine wave signal HS ₂ output from the magnetoelectric converter 15, and uses the corrected cosine wave signal HS ₁ ′ and sine wave signal HS ₂ ′. The magnetic flux angle θ _b is obtained (see equations (6) and (7)), and the magnetic flux angle θ _b is corrected by equation (9). Thereby, the true second magnetic flux angle θ ₂ and the second magnetic flux angular velocity ω ₂ can be obtained.

The speed / angle switching unit 13 selects the true second magnetic flux angle θ ₂ and the second magnetic flux angular velocity ω ₂ obtained by the second detection unit 31 and outputs them as the magnetic flux angle θ ₃ and the magnetic flux angular velocity ω ₃ . . Further, the current switching unit 6 selects the second q-axis current command i _q2 from the torque sensor 4 and outputs this as the q-axis current command i _q .

The current-voltage conversion unit 7 refers to the magnetic flux angle θ ₃ (= second magnetic flux angle θ ₂ ) and magnetic flux angular velocity ω ₃ (= second magnetic flux angular velocity ω ₂ ) output from the speed / angle switching unit 13. However, the d-axis voltage command V _d and the q-axis voltage command V _q are set such that the q-axis current I _q becomes equal to the q-axis current command i _q and the d-axis current I _d becomes equal to the d-axis current command i _d. The motor 21 is output and vector controlled.

As described above, according to the motor control device 1 of the present invention, the cosine wave signal HS ₁ and the sine wave signal HS ₂ output from the magnetoelectric converter 15 are corrected and corrected in the correction mode. by correcting in square theta _a, without a special conditions such as no load, the true flux angle of the motor is possible to obtain the (second flux angle theta ₂₎ and the magnetic flux angular velocity (second magnetic flux angular velocity omega ₂₎ it can. The motor 21 can be controlled with high accuracy in accordance with the operation of the steering 3 by referring to the magnetic flux angle and the magnetic flux angular velocity.

It is a block diagram of a motor control device concerning the present invention. It is a graph of a signal waveform in the correction mode, where (A) is a sine / cosine wave signal before correction, (B) is a sine / cosine wave signal after correction, and (C) is a magnetic flux angle obtained from (B). is there. It is a graph for demonstrating operation | movement of the correction angle measurement part in correction | amendment mode. It is the block diagram which extracted only the part used in correction | amendment mode from FIG. It is a timing chart of correction mode. It is the block diagram which extracted only the part used in normal mode from FIG.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Motor control apparatus 2 Mode control part 3 Steering 4 Torque sensor 5 Speed control part 6 Current switching part 7 Current-voltage conversion part 8 Two-phase-three-phase coordinate conversion part 9 Three-phase-two-phase coordinate conversion part 10 Error angle detection part 11 Proportional / Integral Control Unit 12 Angle Conversion Unit 13 Speed / Angle Switching Unit 14 Divider 15 Magnetoelectric Converter 16 Angle Detection Unit 17 Speed Conversion Unit 18 Correction Value Measurement Unit 19 Correction Angle Measurement Unit 20 Storage Unit 30 First Detection Unit 31 Second detection unit

Claims (4)

A motor control device that controls a motor by vector control based on d-axis and q-axis command currents,
Based on the d-axis and q-axis command current and the d-axis and q-axis current of the motor, the d-axis current becomes equal to the d-axis command current, and the q-axis current becomes equal to the q-axis command current. A first detector for outputting the first magnetic flux angle and the first magnetic flux angular velocity of the motor;
A pair of magnetoelectric transducers provided in or near the motor and outputting a sine wave signal and a cosine wave signal according to the relative positional relationship between the stator and rotor of the motor;
Based on the sine wave signal and the cosine wave signal, the second magnetic flux angle of the motor such that the d-axis current is equal to the d-axis command current and the q-axis current is equal to the q-axis command current; A second detector for outputting a second magnetic flux angular velocity;
In response to a command from the outside, a correction mode in which the motor that is unloaded based on the first magnetic flux angle and the first magnetic flux angular velocity is operated at a constant speed by vector control, the second magnetic flux angle, and the second magnetic flux A mode control unit that switches between a normal mode in which the motor is normally operated by vector control based on an angular velocity;
A correction angle measurement unit that measures a phase shift amount of the second magnetic flux angle with respect to the first magnetic flux angle and outputs the shift amount as a correction angle during the correction mode;
A storage unit for storing the correction angle;
And the second magnetic flux angle output from the second detector in the normal mode is corrected by the correction angle. A correction value measuring unit that measures the amplitude and offset of the sine wave signal and the cosine wave signal during the correction mode, and outputs the amplitude and offset as a correction value;
The storage unit further stores the correction value,
The second detector corrects the sine wave signal and the cosine wave signal with the correction value, and based on the corrected sine wave signal and cosine wave signal, the second magnetic flux angle and the second magnetic flux of the motor. The motor control device according to claim 1, wherein the motor control device outputs an angular velocity.   The motor control device according to claim 2, wherein the correction angle and the correction value are average values during the constant speed operation of the motor. A forklift that includes the motor control device according to any one of claims 1 to 3 and controls an EPS motor by the motor control device,
The forklift characterized in that the q-axis command current increases or decreases in accordance with a torque applied to the steering, and the d-axis command current is constant.

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