JPH0642789B2 - Control device for compressor electric motor - Google Patents

Description

Description: TECHNICAL FIELD The present invention relates to a controller for a compressor electric motor that drives a compressor in which a load applied to an output shaft fluctuates in the same pattern during one rotation.

(Prior Art) Conventionally, in a compressor that repeats a cycle of suction, compression, and discharge during one rotation, a considerably large vibration is generated during operation, and in an air conditioner or the like incorporating this, the vibration of the compressor is reflected in the housing. It was transmitted and generated vibration (resonance) of the entire housing and noise due to vibration.

For this reason, conventionally, measures against this vibration noise have been taken by means such as providing a vibration damping material to the compressor.

(Problems to be Solved by the Invention) However, means such as providing a vibration damping material to the compressor only suppresses the vibration of the compressor from the outside, and is not a drastic measure.

An object of the present invention is to fundamentally and effectively suppress the vibration generation of a compressor.

Hereinafter, vibration generation of the conventional compressor will be described.

In a motor that drives a compressor that repeats suction, compression, and discharge cycles during one rotation, the load applied during one rotation of its output shaft fluctuates in substantially the same pattern as shown in FIG. 1 (C).

On the other hand, the voltage and current patterns supplied to the conventional motor have the waveforms shown in FIG. 1 (A) and the rotation patterns shown in FIG. 1 (B) so that the same torque is output during one rotation. It obtains a magnetic field.

However, when the load torque is applied as shown in FIG. 6C, the speed changes as shown in FIG. That is, during the compression process, a large load torque is applied to the output shaft of the electric motor, so the rotation speed decreases, and when the load applied to the output shaft is small like in the suction process, the rotation speed increases, and a large speed difference occurs during one rotation. It was found that this causes vibration.

(Means for Solving the Problem) The present invention relates to a compressor electric motor in which an output shaft is directly connected to a compressor that repeats a cycle of suction, compression, and discharge during one rotation, and is applied during one rotation of the output shaft. In a control device for a compressor electric motor, in which the speed during one rotation changes as the load changes in accordance with the cycle of suction, compression, and discharge, rotation is performed so as to suppress speed fluctuation during one rotation of the compressor electric motor. It is characterized by comprising a converter for controlling the current supplied to the compressor electric motor therein.

(Operation) Since the converter controls the current supplied to the rotating compressor electric motor so as to suppress the speed fluctuation during one rotation, the vibration of the compressor is suppressed.

(Embodiment) Hereinafter, the present invention will be described based on an embodiment shown in the drawings.

In FIG. 2, reference numeral 1 denotes an electric motor that drives the compressor 2, and its output shaft is directly connected to the compressor 2. This electric motor 1 is a converter 4
Is connected to the power source 5 through the converter, and the converter 4 can change the voltage supplied to the electric motor 1 in synchronization with the rotation of the electric motor 1. That is, as shown in FIG. 3 (A), the load torque applied during one rotation of the output shaft 3 of the electric motor 1 that drives the compressor 2 gradually increases from 0 ° to 360 °. In the case of the pattern, as shown in FIG. 2B, the converter 4 is the output shaft 3 of the electric motor 1.
Is controlled in synchronism with the rotation of, and converted into a current according to the load pattern.

Therefore, the current corresponding to the load torque applied to the output shaft 3 is supplied, and the strength of the magnetic field according to the load as shown in FIG. Therefore, it is possible to suppress a change in speed of the output shaft 3 of the electric motor 1 during one rotation, and it is possible to substantially eliminate vibration of the compressor 2.

(Effects of the Invention) As described above, the present invention is a compressor motor in which an output shaft is directly connected to a compressor that repeats a cycle of suction, compression, and discharge during one rotation, and the output shaft is rotated during one rotation. In a control device for a compressor electric motor in which the speed during one rotation changes due to such a load changing in accordance with a cycle of suction, compression, and discharge, it is possible to suppress speed fluctuation during one rotation of the compressor electric motor. Since the converter for controlling the current supplied to the rotating compressor electric motor is provided, it is possible to supply a current commensurate with the load torque of the compressor electric motor and reduce the occurrence of vibration of the compressor. .

[Brief description of drawings]

1 (A) to 1 (D) are conventional explanatory diagrams, (A) is a current waveform diagram, (B) is an explanatory diagram showing the strength of a magnetic field, and (C) is a curve diagram showing changes in load torque. , (D) is a curve diagram showing changes in rotation speed, FIG. 2 is a schematic configuration diagram showing one embodiment of the present invention, and FIGS. 3 (A) to (C) are explanatory views of the same embodiment.
(A) is a load torque curve diagram, (B) is a current waveform diagram,
(C) is an explanatory view showing the strength of the magnetic field. 1 ... Electric motor, 2 ... Compressor, 3 ... Output shaft, 4 ... Converter, 5
…Power supply.

Claims (2)

[Claims] 1. An electric motor for a compressor, an output shaft of which is directly connected to a compressor which repeats a cycle of suction, compression and discharge during one rotation.
In a control device for a compressor electric motor in which the speed applied during one revolution of the output shaft changes according to the cycle of suction, compression, and discharge, the speed of the electric motor for revolution changes. A compressor provided with a converter for controlling a current supplied to the rotating compressor electric motor so as to suppress speed fluctuation during one rotation of the compressor electric motor. Electric motor controller. 2. The converter controls the current supplied to the compressor electric motor by varying the voltage applied to the rotating compressor electric motor. A control device for an electric motor for a compressor as described.