Control method and device for starting and stopping of compressors in parallel connection unit

Abstract

The invention discloses a control method and device for starting and stopping of compressors in a parallel connection unit. By optimizing the running time of the compressors, reliable running of the system is guaranteed. The method includes the following steps that the gas sucking pressure p of the parallel connection refrigerating unit is acquired, and is compared with the machine increasing pressure p and the machine decreasing pressure pj; and the accumulated running time of the standby compressors is read, and the compressors are controlled to be started and stopped orderly according to the principle that the compressor shortest in accumulated running time is firstly started and the compressor longest in accumulated running time is firstly shutdown. According to the control method, bycomparing the total accumulated running time of the compressors, the compressors are controlled to start and stop, the running time of the compressors is made uniform, starting and stopping are made in order, and the reliability of the system is improved. The possibility that the compressors in the refrigerating parallel connection unit break down is reduced, the service life of the whole refrigerating parallel connection compressors is prolonged, and the problem that the service life of the compressors is not matched with the service life of other devices of the refrigerating parallel connection unit is solved.

Description

technical field [0001] The invention relates to the technical field of refrigeration, and more specifically relates to a control method and a control device for starting and stopping compressors in a parallel unit. Background technique [0002] With the continuous advancement of refrigeration technology, parallel refrigeration units have been widely used due to their high reliability and low operating costs. [0003] In the design of parallel refrigeration units, the peak value in summer is used as the design basis. However, the capacity used at night in winter is about 20% of the total capacity, and the load fluctuates greatly. During the operation of refrigeration parallel units, it is often necessary to increase or reduce the number of compressors in operation. Each compressor is often started and stopped according to the suction pressure. In the refrigeration parallel unit, the suction pressure is higher than the set value, and a signal for requesting compressor increa...

AI Technical Summary

Problems solved by technology

The disadvantage of the above three control methods is that the cumulative running time of the compressors in the parallel unit is not uniform. The long-term operation of the refrigeration parallel unit will definitely lead to the cumulative running time of some compressors in the parallel unit. The accumulative running time of the compressor is short, but the life of the compressor is fixed, resulting in the failure of the compressor with a long running time first or a higher probability of failure

In the refrigeration parallel unit, when any one or more compressors fail, it should not be replaced. Therefore, the faulty compressor reduces the service life of the entire parallel unit and increases the operating cost of the refrigeration system; moreover, the compressor After a failure, if it cannot be repaired in time, the refrigeration system may not be able to resume work in time, causing damage to the valuables stored in it and causing losses; more importantly, among the above three control methods, only the control object compressor sends The control signal does not have a feedback link to detect whether the compressor is running, and the system is not reliable

[0004] Although there is a technical solution for recording the running time of the compressor in the prior art, the recorded running time is only used as a recorded data for viewing and does not participate in the control

Images