JP2004019461A - Control device for compressor motor - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a control device for a compressor motor, suppressing the rotating vibration of the compressor even when an error occurs in a compression starting position. <P>SOLUTION: The control device for the compressor motor controls the driving voltage of a motor by multiplying an average voltage command corresponding to a deviation in the rotating number of the motor 3 for driving the compressor by a torque control pattern changing corresponding to a change pattern of loading torque during one rotation of the motor. It comprises a compression starting position detection part 11 for detecting the compression starting position of the compressor, a rotating number variation detection part 20 for detecting the variation of the rotating number of the motor, correction parts 21, 22 for correcting the detected compression starting position in accordance with the detected variation of the rotating number, and a torque control pattern storage part 12 storing the torque control patterns. The driving voltage of the motor is controlled by multiplying the average voltage command by the torque control pattern read out of the torque control pattern storage part at a timing for the compression starting position corrected by the correction part. <P>COPYRIGHT: (C)2004,JPO

Description

[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to a control device for a motor for a compressor, and more particularly to a technique for reducing vibration of a motor driving the compressor.
[0002]
[Prior art]
Conventionally, a control device for controlling an electric motor for driving a compressor has been known. As such a control device, for example, Japanese Patent Application Laid-Open No. 2001-295969 discloses a "control device for a compressor motor" that can reduce rotational vibration generated due to imbalance between the drive torque and the load torque of the compressor. Has been disclosed.
[0003]
The control device for the compressor motor includes a storage unit in which a coefficient that changes in a pattern corresponding to a change pattern of the load torque during one rotation of the compressor is stored in advance as a torque control pattern. Then, the rotation angle of the motor is detected, a coefficient corresponding to the detected rotation angle is read from the storage means, and the read coefficient is multiplied by an average voltage command corresponding to the rotation speed deviation of the motor to obtain a new voltage command. Is generated, and the motor is driven based on the generated new voltage command so that the torque of the motor follows a change in the load torque during one rotation.
[0004]
[Problems to be solved by the invention]
The compressor motor control device described above detects the compression start position of the compressor and starts reading the torque control pattern based on the detected compression start position. Then, a new voltage command is generated based on the torque control pattern to drive the motor.
[0005]
However, since the compression start position is determined mechanically, when the stator of the motor is incorporated into the compressor during the manufacture of the compressor, a variation occurs in the installation angle and an installation error occurs. As a result, a displacement occurs at the compression start position, causing rotational vibration.
[0006]
Therefore, an object of the present invention is to provide a control device for a compressor motor that can suppress rotational vibration even if an error occurs in the compression start position of the compressor.
[0007]
[Means for Solving the Problems]
The means for solving the problem will be described below using the numbers and symbols used in [Embodiments of the Invention]. These numbers and symbols are added to clarify the correspondence between the description of [Claims] and the description of [Embodiments of the Invention]. It should not be used to interpret the technical scope of the described invention.
[0008]
In order to achieve the above object, the control device for a motor for a compressor according to the present invention provides an average voltage command corresponding to a rotation speed deviation of the motor (3) for driving the compressor during one rotation of the motor (3). A control device for a motor for a compressor for controlling a drive voltage of a motor (3) by multiplying a torque control pattern that changes in accordance with a change pattern of a load torque of the compressor, and detects a compression start position of the compressor. A compression start position detection unit (11), a rotation speed fluctuation width detection unit (20) for detecting a fluctuation width of the rotation speed of the electric motor (3), and a compression start position detected by the compression start position detection unit (11). A correction unit (21, 22) for correcting based on the fluctuation width of the rotation speed detected by the rotation speed fluctuation detection unit (20), and a torque control pattern storage unit (12) storing the torque control pattern. And the correction unit (21, 2 The driving voltage of the electric motor (3) is controlled by reading out the torque control pattern from the torque control pattern storage unit (12) at the timing of the compression start position corrected in the above) and multiplying the torque control pattern by the average voltage command. .
[0009]
According to the control device for the compressor motor, the compressor is operated after the compression start position detected by the compression start position detection unit (11) is corrected so that the rotation frequency oscillation width is minimized. When manufacturing the compressor, when the stator of the electric motor (3) is installed in the compressor, even if the installation angle varies and an installation error occurs, rotational vibration can be suppressed.
[0010]
In the control device for a motor for a compressor according to the present invention, the correction units (21, 22) start compression in which a correction value is generated based on the rotation speed fluctuation width from the rotation speed fluctuation width detection unit (20). The compression start position is corrected by adding the correction values generated by the position correction unit (21) and the compression start position correction unit (21) to the compression start position detected by the compression start position detection unit (11). And an adder (22).
[0011]
Further, in the control device for a motor for a compressor according to the present invention, the compression start position correction unit (21) includes a correction value generated by the compression start position correction unit (21) when the electric motor (3) is under a constant load. Can be added to the compression start position detected by the compression start position detection unit (11).
[0012]
Furthermore, the control device for a compressor motor according to the present invention further includes a load state detection unit (30) for detecting a load state of the motor (3), and the compression start position correction unit (21) includes a load state detection unit. When the load state detected in (30) is constant, the correction value generated by the compression start position correction unit (21) is added to the compression start position detected by the compression start position detection unit (11). It can be configured as follows.
[0013]
According to this configuration, it is possible to determine whether the load state is constant by the load state detection unit (30). Therefore, it is necessary to wait for a predetermined standby time to elapse as a time until the load is stabilized. Therefore, the correction value of the compression start position can be quickly determined.
[0014]
BEST MODE FOR CARRYING OUT THE INVENTION
Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings. The control device for a compressor motor according to the present embodiment is an improvement of the control device for a compressor motor disclosed in Japanese Patent Application Laid-Open No. 2001-29569. Therefore, in the following, the description of the overlapping portion will be simplified, and therefore, please refer to JP-A-2001-29569 as needed.
[0015]
(Embodiment 1)
FIG. 1 is a diagram showing a configuration of a control device for a compressor electric motor according to Embodiment 1 of the present invention. The control device for the compressor motor includes a converter circuit 1, an inverter circuit 2, a DC brushless motor 3, a rotation speed / rotation angle detection unit 10, a compression start position detection unit 11, a torque control pattern storage unit 12, an adder 13, It comprises a proportional / integral constant section 14, a changeover switch 15, a constant generation section 16, a multiplier 17, an inverter UVW waveform control section 18, a rotation speed fluctuation width detection section 20, a compression start position correction section 21, and an adder 22. .
[0016]
Converter circuit 1 is a well-known circuit that converts power from an AC power supply into DC power and supplies it to inverter circuit 2. The inverter circuit 2 converts the DC power from the converter circuit 1 into three-phase power according to a control signal from the inverter UVW waveform control unit 18 and supplies the power to the DC brushless motor 3. The DC brushless motor 3 is a DC motor that drives a compressor (not shown).
[0017]
The rotation speed / rotation angle detection unit 10 detects the rotation speed and rotation angle based on the induced voltage of the DC brushless motor 3. Specifically, the rotation speed / rotation angle detection unit 10 detects the rotation speed of the DC brushless motor 3 based on the interval between the induced voltage zero-cross points, that is, the period of the induced voltage, and detects the induced voltage at the zero-cross point. Each time it passes, it detects that the rotation angles are 0 °, 90 °, 180 ° and 270 °. The rotation speed detected by the rotation speed / rotation angle detection unit 10 is sent to the adder 13 and the rotation speed fluctuation width detection unit 20, and the rotation angle is sent to the compression start position detection unit 11 and the inverter UVW waveform control unit 18. Sent.
[0018]
The compression start position detector 11 detects a compression operation start timing at which a compressor (not shown) coupled to the DC brushless motor 3 starts a compression operation. The rotation angle of the rotor of the DC brushless motor 3 when the compressor starts the compression operation is mechanically determined in advance. The compression start position detection unit 11 detects a timing at which the rotation angle of the DC brushless motor 3 detected by the rotation speed / rotation angle detection unit 10 reaches a predetermined rotation angle as a compression operation start timing of the compressor. Is sent to the adder 22.
[0019]
The adder 22 calculates a new compression start position by adding a correction value from a compression start position correction unit 21 to a signal indicating a compression operation start timing from the compression start position detection unit 11. The signal indicating the new compression start position output from the adder 22 is sent to the torque control pattern storage unit 12.
[0020]
The torque control pattern storage unit 12 stores a torque control pattern deviation table. Torques T1 to T6 shown in FIG. 2 indicate average values of the load torque of the compressor in each of the six rotation angle sections divided at intervals of 60 °. The output voltage of the inverter circuit 2 necessary for generating each of the load torques T1 to T6 can be obtained by calculation or simulation. Also, the average load torque Tav during one rotation of the compressor can be obtained by calculation or simulation.
[0021]
Assuming that the output voltages of the inverter circuit 2 required for generating the torques T1 to T6 are V1 to V6 and the output voltage of the inverter circuit 2 required for generating the average load torque Tav is Vav, the torque control pattern deviation table is as shown in FIG. 3, that is, the relationship between the control coefficient values (V1 / Vav) to (V6 / Vav) obtained by dividing each of the voltages V1 to V6 by the voltage Vav, and each rotation angle interval corresponding to these control coefficient values. I remember the relationship. The control count value stored in the torque control pattern storage unit 12 is sent to the multiplier 17 via the changeover switch 15.
[0022]
The adder 13 calculates a target rotation speed of the compressor (a target rotation speed of the DC brushless motor 3) given from the outside as a rotation speed command and an actual rotation speed of the compressor detected by the rotation speed / rotation angle detection unit 10. (Rotational speed deviation) is calculated. The rotational speed deviation output from the adder 13 is sent to a proportional / integral constant unit 14.
[0023]
The proportional / integral constant section 14 performs proportional / integral compensation on the rotational speed deviation from the adder 13, and outputs a voltage Vav corresponding to the average value of the rotational speed deviation of the compressor as an average voltage command. The average voltage command output from the proportional / integral constant section 14 is sent to the multiplier 17.
[0024]
The changeover switch 15 is turned on when the target rotation speed of the compressor is within a predetermined low rotation speed range. Then, the output of the torque control pattern storage unit 12 is selected in the on state. On the other hand, in the off state, the control coefficient value “1” generated by the constant generator 16 is selected and output.
[0025]
The multiplier 17 multiplies the average voltage command output from the proportional / integral constant section 14 by the control coefficient value selected by the changeover switch 15 and sends the multiplication result to the inverter UVW waveform control section 18 as a voltage command.
[0026]
The inverter UVW waveform control unit 18 has a PWM signal generation function, and based on the rotation angle detected by the rotation speed / rotation angle detection unit 10 and the voltage command from the multiplier 17, performs UVW voltage control on the voltage command. Convert to a signal. This UVW voltage control signal is sent to the inverter circuit 2.
[0027]
The rotation speed fluctuation width detection unit 20 detects a rotation speed fluctuation width r1 indicating the difference between the maximum rotation speed and the minimum rotation speed during one rotation based on the rotation speed detected by the rotation speed / rotation angle detection unit 10. I do. The detected rotational speed fluctuation width r1 is sent to the compression start position correction unit 21.
[0028]
The compression start position correction unit 21 generates a correction value for correcting the compression start position detected by the compression start position detection unit 11 based on the rotation speed fluctuation width r1 from the rotation speed fluctuation detection unit 20. The generated correction value is sent to the adder 22. The correction value output from the compression start position correction section 21 is configured to be fixed by activating a fixed signal (not shown).
[0029]
Next, the operation of the control device for a compressor motor according to Embodiment 1 of the present invention configured as described above will be described.
[0030]
First, the operation of correcting the compression start position of the compressor will be described. In this case, the DC brushless motor 3 is rotated at a constant load and a constant rotation speed. As the condition of the constant load, a standby time until the load is stabilized at a constant rotation speed (a certain frequency) can be adopted.
[0031]
In this state, the rotation speed / rotation angle detection unit 10 detects the rotation speed of the DC brushless motor 3 and sends it to the rotation speed fluctuation width detection unit 20. The rotation speed fluctuation width detection unit 20 detects the rotation speed fluctuation width r1 based on the received rotation speed and sends it to the compression start position correction unit 21. Accordingly, the compression start position correction unit 21 generates a correction value that minimizes the rotation speed fluctuation width r1 and sends the correction value to the adder 22.
[0032]
Here, in the compression start position correction unit 21, a correction value that minimizes the rotation speed fluctuation width r1 can be obtained by the following procedure. That is, the compression start position correction unit 21 sends a plurality of correction values to the adder 22, and collects the rotation speed fluctuation width for each correction value detected by the rotation speed fluctuation width detection unit 20. Then, the correction value corresponding to the smallest one of the collected rotation speed fluctuation widths is determined as the correction value at which the rotation speed fluctuation width r1 is minimized. Thereafter, the fixed signal is activated, and the compression start position correction unit 21 outputs the determined correction value in a fixed manner. Since the built-in angle of the stator of the compressor is uniquely determined by the structure of the compressor, the above-described operation needs to be performed only once during the operation of the compressor.
[0033]
Next, the operation of the control device for the compressor motor will be described. In this case, it is assumed that the compression start position correction unit 21 is set to output a correction value that minimizes the rotation speed fluctuation width r1 by the above-described operation.
[0034]
Assuming that the target rotation speed is set to a rotation speed higher than the rotation speed in the low rotation speed range, the changeover switch 15 is turned off. As a result, the output of the proportional / integral constant section 14 is multiplied by the coefficient “1” from the constant generating section 16 in the multiplier 17. Accordingly, the output of the proportional / integral constant section 14 is directly sent to the inverter UVW waveform control section 18.
[0035]
That is, since the proportional / integral constant section 14 outputs an average voltage command obtained by averaging the rotational speed deviation output from the adder 13, the average voltage command is output when the changeover switch 15 is turned off. The command is directly input to the inverter UVW waveform control unit 18. Thereby, the inverter UVW waveform control unit 18 sends a UVW voltage control signal corresponding to the average voltage command to the inverter circuit 2, and as a result, the DC brushless motor 3 is driven to generate the average torque Tav.
[0036]
Next, when the target rotation speed is set to the rotation speed in the low rotation speed range, the changeover switch 15 is turned on. Therefore, the multiplier 17 multiplies the average voltage command output from the proportional / integral constant section 14 by the torque control pattern output from the torque control pattern storage section 12.
[0037]
The compression start position detection unit 11 detects a timing at which the rotation angle reaches a predetermined rotation angle as a compression operation start timing of the compressor, and sends a signal indicating that to the adder 22. On the other hand, the compression start position correction unit 21 sends the fixed correction value to the adder 22. The adder 22 adds the signal from the compression start position detection unit 11 and the signal indicating the correction value from the compression start position correction unit 21 and sends the result to the torque control pattern storage unit 12. As a result, at the timing when the rotation angle of the compressor becomes an accurate control start angle, reading of the contents stored in the torque control pattern storage unit 12 is started. Thus, from the torque control pattern deviation table, every time the rotation angle increases by 60 ° from the control start angle, the torque control pattern deviation α, that is, the control coefficient values V1 / Vav, V2 / Vav,. Vav is sequentially output.
[0038]
As described above, since the proportional / integral constant unit 14 outputs the voltage Vav corresponding to the average torque Tav, and the torque control pattern storage unit 12 outputs the torque control pattern α, the voltages V1, V2, ... V6 are sequentially output as new voltage commands. As a result, the torque of the DC brushless motor 3 changes in a manner of T1, T2,..., T6 during one rotation of the compressor, as shown in FIG. That is, it changes in accordance with the magnitude of the load torque and in accordance with the change in the load torque.
[0039]
According to the control device for a compressor motor according to the first embodiment of the present invention described above, the compression start position detected by the compression start position detection unit 11 is corrected so that the rotation frequency vibration width is minimized. Since the compressor is operated later, when the compressor is manufactured, when the stator of the DC brushless motor 3 is incorporated in the compressor, even if a variation occurs in the installation angle and an installation error occurs, the rotational vibration can be suppressed. it can.
[0040]
(Embodiment 2)
The control device for a compressor motor according to the second embodiment of the present invention is configured by adding a load state detection unit 30 to the control device for a compressor motor according to the first embodiment described above.
[0041]
The load state detection unit 30 receives the PWM signal at a constant rotation speed generated by the inverter UVW waveform control unit 18. Then, it is checked whether the duty ratio of the input PWM signal is within a predetermined range, and when it is detected that the duty ratio is within the predetermined range, a constant load signal indicating that the engine is in a constant load state at a constant rotation speed is transmitted to the compression start position. It is sent to the correction unit 21.
[0042]
The compression start position correction unit 21 corrects the compression start position of the compressor described in the first embodiment assuming that the condition of the constant load is satisfied when the constant load signal is sent from the load state detection unit 30. Perform the operation of
[0043]
According to the control device for a compressor motor according to the second embodiment, the load state detection unit 30 can determine whether the condition of the constant load is satisfied. There is no need to wait for the waiting time to elapse. Therefore, the correction value of the compression start position can be quickly determined.
[0044]
【The invention's effect】
As described in detail above, according to the present invention, it is possible to provide a control device for a compressor motor that can suppress rotational vibration even if an error occurs in the compression start position of the compressor.
[0045]
More specifically, according to the compressor motor control device of the present invention, after the compression start position detected by the compression start position detection unit is corrected so that the rotation frequency vibration width is minimized, the operation of the compressor is started. Therefore, when manufacturing the compressor, when the stator of the electric motor is installed in the compressor, even if the installation angle varies and an installation error occurs, the rotational vibration can be suppressed.
[0046]
Further, since the load state detector can determine whether the load state is constant, there is no need to wait for a predetermined standby time to elapse before the load is stabilized, and the compression start position can be corrected. The value can be determined quickly.
[Brief description of the drawings]
FIG. 1 is a diagram showing a configuration of a control device for a motor for a compressor according to a first embodiment of the present invention.
FIG. 2 is a diagram illustrating a change pattern of a drive torque with respect to a change pattern of a load torque in a control device for a compressor motor according to a first embodiment of the present invention.
FIG. 3 is a diagram showing stored contents of a torque control pattern deviation table in the compressor motor control device according to the first embodiment of the present invention.
FIG. 4 is a diagram showing a configuration of a control device for a compressor motor according to a second embodiment of the present invention.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 Converter circuit 2 Inverter circuit 3 DC brushless motor 10 Number of rotations / rotation angle detection unit 11 Compression start position detection unit 12 Torque control pattern storage unit 13 Adder 14 Proportional / integral constant unit 15 Switch 16 Constant generation unit 17 Multiplier 18 Inverter UVW waveform control unit 20 Rotation speed fluctuation width detection unit 21 Compression start position correction unit 22 Adder

Claims (4)

The driving voltage of the motor is obtained by multiplying an average voltage command corresponding to a rotational speed deviation of the motor driving the compressor by a torque control pattern that changes in accordance with a change pattern of the load torque during one rotation of the motor. A control device for a compressor electric motor to be controlled,
A compression start position detection unit that detects a compression start position of the compressor,
A rotation speed fluctuation width detection unit that detects a fluctuation width of the rotation speed of the electric motor,
A correction unit that corrects the compression start position detected by the compression start position detection unit based on the fluctuation width of the rotation speed detected by the rotation speed fluctuation width detection unit,
A torque control pattern storage unit storing the torque control pattern,
A control of a motor for a compressor that controls the drive voltage of the motor by reading the torque control pattern from the torque control pattern storage unit at the timing of the compression start position corrected by the correction unit and multiplying the torque control pattern by the average voltage command. apparatus. The correction unit,
A compression start position correction unit that generates a correction value based on the fluctuation width of the rotation speed from the rotation speed fluctuation width detection unit,
An adder for correcting the compression start position by adding a correction value generated by the compression start position correction unit to the compression start position detected by the compression start position detection unit;
The control device for a motor for a compressor according to claim 1, comprising: The compression start position correction unit,
The motor for a compressor according to claim 2, wherein a correction value generated by the compression start position correction unit is added to a compression start position detected by the compression start position detection unit when the motor is under a constant load. Control device. Further comprising a load state detection unit for detecting a load state of the electric motor,
The compression start position correction unit detects a correction value generated by the compression start position correction unit in a state where the load state detected by the load state detection unit is constant, and the compression start position detection unit detects the correction value. The control device for a compressor electric motor according to claim 3, wherein the control is added to a compression start position.

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