Method and device for protecting compressor

Abstract

The invention provides a method and device for protecting a compressor. The method comprises the steps that after the compressor receives turnoff signals, the whole machine current value of a mutual inductor in an air conditioner indoor unit is detected within the preset time period; whether the whole machine current value detected within the preset time period is within the preset current value range or not is judged; and according to the judgment result, control instructions are transmitted to the compressor. According to the method and device for protecting the compressor, whether adhesion of an alternating current contactor happens or not is effectively detected without additionally installing devices, and the purpose of protecting the compressor is achieved accordingly.

Description

technical field [0001] The invention relates to the technical field of automatic control, in particular to a method and device for protecting a compressor. Background technique [0002] Traditional low-power air conditioners use relays to control the connection between the compressor and the power supply. When the main controller of the air conditioner issues a command to turn off the compressor, it will cut off the power to the relay coil. After the coil loses its magnetism, the two relays in the relay will The two contacts will be reset under the action of the spring, so that the line between the compressor and the power supply is disconnected, and the compressor is powered off and shut down. With the increasing power of air conditioners, some high-power air conditioners or central air conditioners generally use more than 3 compressors. The traditional relay obviously cannot meet the requirements, so an AC contactor is used to control the on-off of the line. The principle...

AI Technical Summary

Problems solved by technology

[0003] However, in actual operation, the AC contactor of the air conditioner often causes the bonding force between the contacts to exceed the elastic force of the return spring due to the excessive current passing through, resulting in the spring being unable to connect the two contacts after the coil is powered off. The point is separated, or the contact cannot be separated due to the quality problem of the AC contactor, that is, the adhesion of the AC contactor occurs

Once the AC contactor sticks, the compressor will continue to run and cannot be stopped, while the fans of the indoor heat exchanger and outdoor heat exchanger have stopped and cannot exchange heat, causing a large amount of liquid to return to the compressor, which will damage the compressor in the long run

In order to protect the compressor, in the prior art, a current sensor electrically connected to the main controller is often added in the compressor to detect whether the current of the compressor is greater than 0A. When the detected compressor current is greater than 0A for a period of time 0A, it is determined that the AC contactor is stuck, causing the compressor to fail to stop

[0004] However, the above-mentioned prior art has the following problems: by adding a current sensor in the compressor to detect the current of the compressor, it will increase the production cost of the compressor and may even need to change the internal structure of the compressor, which is often not implemented in practice. too convenient

[0005] In view of the above problems, no effective solution has been proposed

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