JPH02142392A - Compressor driver - Google Patents

Abstract

PURPOSE:To prevent the vibration and noise generated in a compressor by apparently canceling the pulsation of a load torque at the time when the compressor makes one revolution. CONSTITUTION:Electric current is rectified by a rectifier circuit 50, converted into AC by an inverter circuit 10, and supplied to a compressor 20. The compressor 20 is fitted with a vibration detector 30, of which output is inputted to a microcomputer 40. The pulsation of a load torque of the compressor 20 is represented by the output of the vibration detector 30. The microcomputer 40 detects the pulsation of the load torque from the output of the vibration detector 30, and controls the pulsation so that the PWM pulse width is made larger when the load torque is large and the PWM signal pulse width is made small when the load torque is small to prevent the pulsation of the load torque.

Description

[Detailed Description of the Invention] <Industrial Application Field> The present invention provides a compressor built into an air conditioner, a refrigerator, etc.
The present invention relates to a compressor drive device driven by a WM type inverter circuit.

<Prior Art> Among household electrical appliances that are becoming increasingly sophisticated, air conditioners, refrigerators, and the like are widely available with built-in inverter circuits that are controlled by microcomputers. The compressor drive unit installed in this type of equipment usually uses PWM (pulse width modulation), which is easy to interface with a microcontroller.
The inverter circuit of this method is adopted.

A conventional compressor drive device generates a PWM signal in a microcomputer according to the set rotation speed of the compressor, operates a PWM inverter circuit based on this PWM signal, and controls the alternating current supplied to the compressor. The configuration is such that this drive is controlled by varying the frequency and level.

<Problems to be Solved by the Invention> However, in the case of the above conventional example, the load torque when the rotor of the compressor rotates once is not constant, and uneven rotation occurs in the rotor of the compressor, causing the compressor to The disadvantage is that it generates vibration and noise. In other words, although you can enjoy many benefits due to the functions of inverter circuits,
Since it generates noise and vibration, the image as a product is poor.

The present invention was devised in view of the above circumstances, and PW
It is an object of the present invention to provide a compressor drive device that can reduce noise and vibration as much as possible even though it has a configuration including an M-type inverter circuit.

<Means for Solving the Problems> A compressor drive device according to the present invention includes: a PWM inverter circuit that supplies power to a compressor; a vibration detector that detects drive vibrations of the compressor; and a PWM signal generating section that generates a PWM signal having a frequency determined by the set rotation speed of the compressor and a pulse width according to the detection result of the vibration detector, and outputs the generated PWM signal to the inverter circuit. .

<Operation> The detection result of the vibration detector provides the vibration level of the compressor, and also provides the load torque of the compressor as information, and the PWM signal generation section generates a pulse width according to the load torque of the compressor. Generate a PWM signal with When this PWM signal is introduced into the inverter circuit, the effective value of the generated alternating current changes, and the driving torque generated in the compressor changes, resulting in fluctuations in the load torque when the compressor rotates once. However, the appearance was canceled out.

<Embodiment> Hereinafter, one embodiment of the compressor drive device according to the present invention will be described with reference to the drawings. FIG. 1 is an electrical configuration diagram of the compressor drive device, and FIG. 2 is a timing chart showing the load torque and vibration detection signal of the compressor.

The compressor drive device described here is a circuit whose main configuration is a PWM inverter circuit 10 that supplies power to a compressor 20 installed in an air conditioner, and which generates a PWM signal generated by a microcomputer 40 serving as a PWM signal generation section. The compressor 20 is driven and controlled by varying the frequency and level of the three-phase alternating current generated by the inverter circuit 10 based on the signal.

Each component will be explained in detail below.

Commercial alternating current supplied to the air conditioner is converted into a direct current voltage by a converter circuit consisting of a guide bridge 50 and a smoothing capacitor 51, and the converted direct current voltage is led to an inverter circuit 10.

The inverter circuit 10 includes a total of six power transistors 1
1 to 16, the power transistor 11
- 16 are controlled respectively, and the basic configuration is such that the input DC voltage is converted into three-phase AC. Note that a flywheel diode 17 for absorbing regenerated power from the compressor 20 is connected between the collector emitters of the power transistors 11 to 16, respectively.

The three-phase alternating current generated by the inverter circuit 10 is applied to a three-phase induction motor in the compressor 20, thereby rotating a rotor connected to the three-phase induction motor. Furthermore, a vibration detector 30 is attached to a predetermined portion of the compressor 20 to detect drive vibrations generated when the rotor is driven to rotate.

The vibration detector 30 is a vibration sensor including, for example, a piezoelectric element, and converts the level of drive vibration of the compressor 20 into a vibration detection signal, which is a voltage signal, and outputs this to the input port of the microcomputer 40. The structure is as follows. Note that, as shown in FIG. 2, the load torque of the compressor 20 pulsates at the same period as the rotation period of the rotor, and this causes vibrations and the like in the compressor 20. Therefore, the vibration detection signal that provides the level of driving vibration of the compressor 20 changes at the same period as the rotation period of the rotor.

Moreover, the vibration detection signal and the load torque of the compressor 20 are
Since the vibration detector 30 is attached to the compressor 20 in a phase relationship that is determined depending on the location, the vibration detection signal is a signal that provides the load torque of the compressor 20.

In addition to its function as a PWM signal generator, the microcomputer 40 also has the function of controlling electrical components (not shown) in the air conditioner. is connected. In addition to the vibration detector 30, a setting section 42 such as a switch is connected to the input port, and through this setting section 42, the timing of starting and stopping the operation of the compressor 20 and the rotation speed setting of the compressor 20 can be set. It is about to be done. The PWM signal output from the output port of the microcomputer 40 will be explained in detail. This PWM signal signal window pulse waveform is composed of a total of three signals that are the same and have a phase shift of 120' from each other, and these signals are the power transistors 11.12, 13.14, and 15.16. It is designed to be introduced in each base.

Moreover, the current driver 41 has an inverter circuit built in, and the PWM signal window phases introduced into the bases of the power transistors 11 and 12 are shifted by 180 degrees from each other.

The same applies to the PWM signal windows introduced to the bases of the power transistors 13, 14 and 15, 16.

Next, in the compressor drive device configured as described above, vibrations generated in the compressor 20 when driving and controlling the compressor 20,
The noise can be suppressed as much as possible, and the principle will be explained along with an explanation of the operation.

First, when the timing for starting operation of the compressor 20 is given through the setting unit 42, the data in the ROM table is sequentially read out at a timing commensurate with the initial setting rotation speed of the compressor 20, and the correction process described below is performed. . The read data that has undergone correction processing is called the PWM signal signal window.
When this is introduced into the inverter circuit 10, a three-phase alternating current based on the PWM signal signal window is generated, and the compressor 20 is started. Note that the ROM table stores in advance PWM signal window value information having a predetermined pulse width.

By the way, the load torque of the compressor 20 during one revolution of the rotor of the compressor 20 pulsates as shown in FIG. It has been introduced. Then, the read data of the ROM table is corrected according to the input load torque. That is, when the detected load torque is large, the data is processed so that the PWM signal window pulse width becomes large, while when the detected load torque is small, the data is processed so that the PWM signal signal window pulse width becomes small. do. In this way, PW
By making the M signal signal window pulse width variable, the effective value of the three-phase AC generated by the inverter circuit 10 is made variable. When the effective value of the three-phase alternating current is made variable in this way, the driving torque of the compressor 20 changes accordingly, and as a result, the pulsation of the load torque when the compressor 20 rotates once becomes The appearance is canceled out, and as a result, even when the compressor 20 is started and reaches the initial set rotation speed, vibrations and noise are minimized. Note that in order to change the set rotation speed of the compressor 20 through the setting unit 42, the ROM
The only difference is the timing of reading data from the table, and the other circumstances are exactly the same.

Therefore, in the compressor drive device according to the present embodiment, by simply adding the vibration detector 30 and slightly changing the program of the microcomputer 40, the rotor of the compressor 20 rotates smoothly, and vibrations and noise are suppressed as much as possible. be able to. Therefore, the commercial value of the air conditioner can be increased.

Note that the compressor drive device according to the present invention can of course be applied not only to air conditioners but also to refrigerators and the like, and the PWM signal generation section may be an analog circuit consisting of a sawtooth wave generation circuit, a comparator circuit, etc.

<Effects of the Invention> As described above, the compressor drive device according to the present invention is configured such that the pulsation of the load torque when the compressor rotates once is canceled out, so that the compressor The rotor rotates smoothly, and vibrations and noise generated in the compressor can be reduced as much as possible.

[Brief explanation of the drawing]

1 and 2 are diagrams for explaining one embodiment of the compressor drive device according to the present invention, and FIG. 1 is an electrical configuration diagram of the compressor drive device, load torque and vibration of the compressor. 3 is a timing chart showing a detection signal. 10・ 20・ 30・ 40・ ・Inverter circuit・Compressor・Vibration detector・Microcomputer・PWM signal

Claims (1)

[Claims] (1) A PWM inverter circuit that supplies power to the compressor, a vibration detector that detects drive vibrations of the compressor, and a vibration detector that detects the vibrations at a frequency determined by the set rotation speed of the compressor. A compressor drive device comprising: a PWM signal generation section that generates a PWM signal having a pulse width according to a detection result of a detector and outputs the generated PWM signal to the inverter circuit.