Staged synchronous compressor and expansion valve control method for thermostatic and humidistatic air conditioning unit

Abstract

The invention relates to a staged synchronous compressor and expansion valve control method for a thermostatic and humidistatic air conditioning unit. The control method includes the steps: dividing system control into a coarse control stage and a fine control stage according to the starting state and the normal running state of the air conditioning unit, performing preset open-loop control at the coarse control stage by increasing the frequency of the compressor at the speed of 3Hz / s to the highest frequency for the compressor to run and setting the openness of the electronic expansion valve to reach 50%-70%; and performing synchronous compressor and expansion valve closed-loop control at the fine control stage by performing adaptive PID (proportion integration differentiation) adjustment according to inputted indoor and outdoor temperature and humidity change and change rate, superheat degree and superheat degree change rate, outputting frequency signals of the compressor and openness signals of the expansion valve, and controlling the rotation speed of the compressor and the opening pulse of the expansion valve to realize synchronous control. The time of temperature and humidity fluctuation of a controlled environment at the starting stage of the thermostatic and humidistatic air conditioning unit or due to external interference with the thermostatic and humidistatic air conditioning unit can be greatly shortened, and delay and over-control of the system control due to respectively independent control for the compressor and the expansion valve are relieved.

Description

technical field [0001] The invention belongs to the technical field of air-conditioning control, in particular to a stage-by-stage compressor-expansion valve synchronous control method applied to a constant-temperature and constant-humidity air conditioner, which can realize high-precision control of the temperature and humidity of the constant-temperature and constant-humidity air conditioner. Background technique [0002] At this stage, the precise control of the control environment of the constant temperature and humidity air conditioner is mainly realized in two ways: one is to precisely control the required cooling capacity (dehumidification capacity) by adjusting the output of the compressor to achieve the high precision requirements of constant temperature and humidity. Compressors with adjustable capacity such as frequency conversion or digital scroll are often needed; the second is to use thyristor PID to adjust the heating and humidification capacity, so as to accur...

AI Technical Summary

Problems solved by technology

[0003] In the frequency conversion or digital scroll constant temperature and humidity air conditioning system control, the current control method often considers the control of the electronic expansion valve and the compressor in isolation, which is prone to hysteresis or overshooting, often making the compressor and the electronic expansion valve in the air. Matching and coordination cannot be achieved in a short period of time. Although the system will tend to be stable for a long time, the air-conditioning environment is often changeable and complex. Once a change occurs, it will take a long time to stabilize the system. The refrigeration system is always running at its best

Images