JP2002039075A - Control method of compressor motor - Google Patents

Abstract

(57) [Summary] [PROBLEMS] To reliably reduce vibration of a compressor. SOLUTION: In step S4, a vibration acceleration is detected in a section where the rotational angle of the compressor motor is 60 degrees. The average value of the vibration acceleration for one rotation is calculated. After that, in step S5, the detection result is compared with the average value, and in step S6, it is determined whether or not the comparison results for a certain number of motors are the same. If “YES” here, the process shifts to the step S7 to correct the PWM duty ratio (applied voltage) for each electrical angle of 60 °. In this case, when the vibration acceleration at each rotation electrical angle of 60 ° is smaller than the average vibration acceleration, the voltage applied to the compressor motor is increased by a predetermined constant width, and the vibration acceleration at each rotation electrical angle of 60 ° is averaged. When it is larger than the vibration acceleration, the voltage applied to the compressor motor is reduced by a predetermined constant width, and when they are equal, the correction of the voltage applied to the compressor motor is not performed.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a compressor motor control method for reducing compressor vibration.

[0002]

Conventionally, there has been a problem that vibration occurs in a compressor. To solve this problem, as disclosed in Japanese Patent Application Laid-Open No. Hei 10-201289, a rotation speed fluctuation during one rotation of the compressor motor is detected, and an application to the compressor motor is made so as to eliminate the speed fluctuation. There is one that corrects the voltage. But,
In this case, it is not always possible to directly reduce the vibration of the compressor itself.

[0003] The present invention has been made in view of the above circumstances, and an object of the present invention is to provide a method of controlling a compressor motor that can reliably reduce the vibration of the compressor.

[0004]

SUMMARY OF THE INVENTION The present invention focuses on the fact that vibration of a compressor can be directly detected by attaching an acceleration sensor to the compressor, and the vibration acceleration is compared for each predetermined electrical angle section. According to the results, attention was paid to the fact that the vibration of the compressor can be reduced by increasing or decreasing the applied voltage in a predetermined electrical angle section unit.

According to a first aspect of the present invention, there is provided a compressor having a compressor motor including a reciprocating-type compression mechanism and a DC brushless motor for driving the compressor, and a method for controlling the compressor motor. An acceleration sensor is attached, the acceleration sensor detects the vibration acceleration of the compressor, and the acceleration sensor averages the vibration acceleration of the compressor for one rotation of the compressor motor by, for example, a microcomputer as a control circuit. The present invention is characterized in that a voltage applied to the compressor motor is corrected for each predetermined rotation electrical angle section of the compressor motor based on the calculated average vibration acceleration. In the method for controlling the compressor motor, the vibration of the compressor can be directly measured by attaching the acceleration sensor to the compressor. Then, an average value of the vibration acceleration of the compressor for one rotation of the compressor motor is calculated by, for example, a microcomputer, and based on the average vibration acceleration, the average value of the compressor motor for each predetermined rotation electrical angle section of the compressor motor is calculated. Is applied, the vibration of the compressor due to the unevenness of the motor rotation speed during one rotation of the compressor motor is reduced. In this case, as described above, since the vibration of the compressor can be directly measured, the vibration of the compressor can be directly reduced.

According to a second aspect of the present invention, the vibration acceleration is detected for each predetermined rotation electrical angle section of the compressor motor, the vibration acceleration in each predetermined rotation electrical angle section is compared with the average vibration acceleration, and each predetermined rotation electrical angle is detected. When the vibration acceleration for each section is smaller than the average vibration acceleration, the voltage applied to the compressor motor is increased. When the vibration acceleration for each predetermined rotation electrical angle section is larger than the average vibration acceleration, the voltage applied to the compressor motor is reduced. It is characterized in that when they are equal, the correction of the voltage applied to the compressor motor is not performed.

When the vibration acceleration of each of the predetermined rotation electrical angle sections of the compressor motor is smaller than the average vibration acceleration, the voltage applied to the compressor motor is increased, and the vibration acceleration of each of the predetermined rotation electrical angle sections is smaller than the average vibration acceleration. When the voltage is large, the voltage applied to the compressor motor is reduced, and when the voltage is equal, the correction of the voltage applied to the compressor motor is not performed. This is very effective in reducing the vibration of the compressor.

According to a third aspect of the present invention, the average vibration acceleration of one rotation of the compressor motor is continuously compared with the vibration acceleration of each predetermined rotation electrical angle section, and the average vibration acceleration is compared with the predetermined rotation electric rotation of the compressor motor. It is characterized in that the voltage applied to the compressor motor is corrected when the result of one comparison with the vibration acceleration detected for each angular section is continuously the same for a predetermined number of times. Even when the compressor is vibrating, the vibration may be reduced at the next point in time. That is, the vibration may be temporary. However, according to the third aspect of the present invention, when the average vibration acceleration and the vibration acceleration detected for each predetermined rotation electrical angle section of the compressor motor for one time are continuously the same, the vibration is temporarily generated. Is not (constant). The reliability of the compressor vibration reduction control is improved by such a method of correcting the applied voltage to the compressor motor.

The invention of claim 4 is characterized in that the applied voltage is corrected in accordance with the difference between the vibration acceleration and the average vibration acceleration for each predetermined electrical angle section. When correcting the voltage applied to the compressor motor, a voltage value that is uniquely determined may be added or subtracted. Correcting the applied voltage according to the difference between the vibration acceleration and the average vibration acceleration makes it possible to correct the appropriate applied voltage.

According to a fifth aspect of the present invention, the compressor motor makes one rotation at a rotation electrical angle of 720 °, and the compressor operates for one cycle in this one rotation, and the predetermined rotation electrical angle section is 60 °.
The feature is that it is set to. When the compressor motor is a three-phase DC brushless compressor motor, the zero-cross interval of each phase is 60 ° (electrical angle). This electrical angle 6
Since 0 ° is used as the rotational electrical angle for measuring the vibration acceleration and correcting the voltage, the electrical angle detection is relatively easy. Also, in the case of a configuration in which the motor makes one rotation at an electrical angle of 720 °, there are 12 voltage correction opportunities for one rotation of the motor, and there is neither too much nor too little. The voltage is corrected at an appropriate number of times by the applied voltage matching the load fluctuation of the motor, which is effective in reducing the vibration.

[0011]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below with reference to the drawings. First, in FIG. 2, a compressor 1 includes a reciprocating compression mechanism 3 inside a closed case 2.
(Shown schematically in FIG. 4) and a compressor motor 4 composed of a DC brushless motor (see FIG. 3, hereinafter referred to as a motor 4). The compression mechanism 3 includes a cylinder 3a and a piston 3b, and performs one cycle of suction and compression (discharge) by one rotation of the motor 4. The motor 4 has three-phase windings 4u, 4u
v, 4w and the position detecting elements 5u, 5w
v, 5w. The compression mechanism 3 is driven by the motor 4, and the compression mechanism 3 operates one cycle for one rotation of the motor 4. The motor 4 makes one rotation at a rotational electrical angle of 720 °.

The inverter main circuit 6 is supplied with a DC power supply Vdc.
Switching elements (IGBT or FET) between a and 6b
7a to 7f are connected in a three-phase bridge, and freewheel diodes 8a to 8f are connected to the switching elements 7a to 7f, respectively, with the polarity shown. The output terminal of each phase bridge is connected to each phase winding 4u, 4v, 4w of the motor 4. That is, the motor 4 is driven by the inverter main circuit 6. The switching elements 7a to 7
f is PWM-controlled by the control circuit 10 via the drive circuit 9.

On the other hand, the compressor 1 is provided with an acceleration sensor 11 composed of, for example, a piezoelectric acceleration sensor. The acceleration sensor 11 detects the magnitude of the acceleration for a very short time and inputs a detection signal to the control circuit 10. In this case, the acceleration sensor 11 detects the magnitude of the acceleration as the magnitude of the vibration.

The control circuit 10 is constituted by a microcomputer having a data input interface from an acceleration sensor and an A / D conversion function. The control circuit 10 includes, as shown in FIG.
Various calculations and controls are executed in response to the input of 1. When a start signal for the compressor 1 is generated, the flowchart of FIG. 1 starts. In step S1, the motor 4 is started with the starting PWM duty ratio. In the next step S2, the unit PWM duty ratio set for each rotation of the motor is added from the starting PWM duty ratio until the specified duty ratio is reached. The motor 4 is started up sequentially. At the time of this PWM control, commutation timing is appropriately set by the position detection elements 5u, 5v, and 5w. In this way, the voltage applied to the motor 4 is gradually increased.

In step S3, the PWM duty ratio is determined according to the difference between the motor rotation speed (which is detected by the position detection means) and the target rotation speed. As a result, the motor 4 is almost constantly rotated. Next step S4
Then, the rotation electric angle of 60 ° which is a predetermined rotation electric angle of the motor 4 is obtained.
In the section, acceleration, that is, vibration acceleration is detected by the acceleration sensor 11. Then, this is detected for one rotation of the motor 4 (720 ° in electrical angle), that is, twelve times for one rotation (the detection results are D1 to D12), and the average value of the vibration acceleration for one rotation is calculated ( The average value is Dave). Dave = (D1 + D2 +... D12) / 12 Then, in step S5, the detection results D1 to D12
And the average value Dave, and the comparison results K1 to K12
Is stored. This is performed a predetermined number of times, for example, two rotations. Note that the previous comparison results are K1 'to K12'. Then, in step S6, it is determined whether or not the above comparison results for two rotations of the motor are the same. That is, the current detection results K1-K corresponding to the previous detection results K1'-K12 '.
It is determined whether or not the result of the comparison with the reference numeral 12 is the same, and the comparison result in the next one rotation is also the same as the previous result.

If "YES" here, a step S7 is carried out.
Move to In step S7, the PWM duty ratio (applied voltage) in the 12 sections (for one rotation) for each electrical angle of 60 ° is corrected. In this case, when the vibration acceleration at each rotation electrical angle of 60 ° is smaller than the average vibration acceleration, the voltage applied to the motor 4 is increased by a predetermined constant width, and the vibration acceleration at each rotation electrical angle of 60 ° becomes the average vibration acceleration. When the acceleration is larger than the acceleration, the voltage applied to the motor 4 is reduced by a predetermined constant width, and when the acceleration is equal, the correction of the voltage applied to the compressor motor is not performed. Thereby, the vibration acceleration in one rotation of the motor 4 becomes uniform. Thereafter, the process proceeds to step S8,
The motor 4 is driven at the currently set PWM duty ratio for each electrical angle of 60 °, and when the motor stop signal is input, the operation of the motor 4 is stopped.

According to this embodiment, the vibration of the compressor 1 can be directly measured by attaching the acceleration sensor 11 to the compressor 1. An average value of the vibration acceleration of the compressor 1 in one rotation of the motor 4 is calculated from the vibration acceleration detected by the acceleration sensor 11 by a microcomputer as a control circuit, and based on the average vibration acceleration, the electric value of the motor 4 is calculated. Since the applied voltage to the motor is corrected every 60 ° section, the vibration acceleration in one rotation of the motor 4 becomes uniform, and the compressor vibration caused by the uneven motor rotation speed is reduced. In this case, as described above, since the vibration acceleration of the compressor 1 can be directly measured, the vibration of the compressor 1 can be directly reduced.

Further, according to the present embodiment, the vibration acceleration is detected for each predetermined rotation electrical angle section of the motor 4, and each of the electrical angles is detected.
The vibration acceleration in the 0 ° section is compared with the average vibration acceleration, and when the vibration acceleration in each predetermined rotation electrical angle section is smaller than the average vibration acceleration, the voltage applied to the motor 4 is increased,
When the vibration acceleration for each predetermined electrical angle section is greater than the average vibration acceleration, the voltage applied to the motor 4 is reduced, and when the vibration acceleration is equal, the correction of the voltage applied to the motor 4 is not performed. It is extremely effective for reduction.

In particular, when the result of one comparison between the average vibration acceleration and the vibration acceleration detected for each electric angle 60 ° section of the motor 4 is constant for a certain number of times, for example, twice, the voltage applied to the compressor motor is Since the correction is performed, the motor 4 is only output when the vibration is not temporary (it is constant).
The voltage applied to the motor can be corrected, and the reliability of the vibration reduction control is improved.

According to the present embodiment, in the motor 4 composed of a three-phase DC brushless motor, the zero-cross interval of each phase is 60 ° (electrical angle), and the electric angle is 60 °.
Is the rotational electrical angle for measuring the vibration acceleration and correcting the voltage, the electrical angle detection is relatively easy. And
Since the motor 4 is configured to make one rotation at a rotational electrical angle of 720 °, there are twelve voltage correction opportunities for one rotation of the motor 4, neither too much nor too little, and the compressor 1 operates for one cycle. Applied voltage correction matching the load state of the compressor motor can be performed, which is effective in reducing vibration.

In the above embodiment, the applied voltage to be corrected is set to a predetermined width in advance. However, this is because the applied voltage is corrected according to the difference between the vibration acceleration and the average vibration acceleration for each predetermined electrical angle section. You may do it. This makes it possible to correct the applied voltage more appropriately.

In step S6 in FIG. 1, the correction execution condition is that the detection result is the same for two rotations of the motor 4, but the correction execution condition is that the detection result is the same for two or more rotations of the motor 4. Is also good. In addition, the present invention is not limited to the above-described embodiment, and can be implemented with various modifications without departing from the scope of the invention.

[0023]

As apparent from the above description, the present invention has the following effects. According to the first aspect of the present invention, the vibration acceleration of the compressor is directly detected, the average vibration acceleration is calculated based on the detection result, and the predetermined rotation electrical angle section of the compressor motor is calculated based on the average vibration acceleration. Since the applied voltage to the compressor motor is corrected every time, the vibration of the compressor can be reduced directly.

According to the second aspect of the present invention, when the vibration acceleration of the compressor motor for each predetermined rotation electrical angle section is smaller than the average vibration acceleration, the voltage applied to the compressor motor is increased, and the predetermined rotation electrical angle section is increased. When the vibration acceleration is larger than the average vibration acceleration, the voltage applied to the compressor motor is reduced, and when the vibration acceleration is equal, the correction of the voltage applied to the compressor motor is not performed. Becomes effective.

According to the third aspect of the invention, the result of one comparison between the average vibration acceleration and the vibration acceleration detected for each predetermined rotation electrical angle section of the compressor motor is continuously the same for a predetermined number of times. It is determined that the vibration generation is not temporary (it is permanent), and when this condition is satisfied, the voltage applied to the compressor motor is corrected. Therefore, the vibration reduction control can be performed only when necessary.

According to the fourth aspect of the present invention, the applied voltage is corrected according to the difference between the vibration acceleration and the average vibration acceleration for each predetermined rotational electrical angle section. Can be.

According to the fifth aspect of the invention, the compressor motor makes one rotation at a rotational electrical angle of 720 °, and the compressor operates for one cycle in this one rotation, and the predetermined rotational electrical angle section is set to 60 °. Therefore, it is relatively easy to measure vibration acceleration and detect a predetermined electrical angle for voltage correction for voltage correction, and to apply an applied voltage correction that matches the compressor motor load state during one cycle of operation of the compressor. Can be performed, which is effective in reducing vibration.

[Brief description of the drawings]

FIG. 1 is a flowchart of a motor control according to an embodiment of the present invention.

FIG. 2 is a front view of the compressor.

FIG. 3 is a diagram showing a motor drive circuit;

FIG. 4 is an operation diagram for explaining an operation.

[Explanation of symbols]

1 is a compressor, 3 is a reciprocating compression mechanism, 4 is a compressor motor, 6 is an inverter main circuit, 9 is a control circuit, and 11 is an acceleration sensor.

 ────────────────────────────────────────────────── ─── Continuing on the front page (72) Inventor Shigeo Hirahara 1-6 Ota Toshiba-cho, Ibaraki-shi, Osaka F-term in the Toshiba Osaka Plant (reference) 3H045 AA03 AA09 AA12 AA25 BA38 CA10 CA21 CA22 DA08 DA45 EA17 EA26 EA34 EA42

Claims (5)

[Claims] In a method for controlling a compressor motor having a compressor motor including a reciprocating compression mechanism and a DC brushless motor for driving the same, an acceleration sensor is attached to the compressor. Detecting the vibration acceleration of the compressor by the acceleration sensor, calculating an average value of the vibration acceleration of the compressor for one rotation of the compressor motor based on the detection result, based on the average vibration acceleration, A method of controlling a compressor motor, wherein a voltage applied to the compressor motor is corrected for each predetermined electrical angle section of the compressor motor. 2. A vibration acceleration is detected for each predetermined rotation electrical angle section of the compressor motor, and the vibration acceleration of each predetermined rotation electrical angle section is compared with the average vibration acceleration. Is smaller than the average vibration acceleration, the voltage applied to the compressor motor is increased. If the vibration acceleration for each predetermined rotation electrical angle section is larger than the average vibration acceleration, the voltage applied to the compressor motor is reduced. 2. The method according to claim 1, wherein the correction of the voltage applied to the motor is not performed. 3. An average vibration acceleration of one rotation of the compressor motor is continuously compared with a vibration acceleration of each predetermined rotation electrical angle section, and the average vibration acceleration is detected for each predetermined rotation electrical angle section of the compressor motor. 3. The method of controlling a compressor motor according to claim 2, wherein the voltage applied to the compressor motor is corrected when the result of one comparison with the obtained vibration acceleration is continuously the same for a predetermined number of times. 4. The control method for a compressor motor according to claim 1, wherein the applied voltage is corrected according to a difference between the vibration acceleration and the average vibration acceleration for each predetermined rotation electrical angle section. 5. The compressor motor has a rotation electrical angle of 720 ° and a rotation angle of 1 °.
5. The control method for a compressor motor according to claim 1, wherein the compressor rotates during one rotation, and the compressor operates for one cycle, and the predetermined rotation electrical angle section is set to 60 [deg.].