Load self-adaptation variable-frequency multi-connection heat pump system and method for controlling compressor frequency

Abstract

The invention discloses a load self-adaptation variable-frequency multi-connection heat pump system and method for controlling compressor frequency. The system comprises indoor units, outdoor units, a frequency control device, and pipes connecting the indoor units and the outdoor units. Each indoor unit is provided with an indoor heat exchanger for indoor heat exchanger. Each outdoor unit is provided with a compressor. The frequency control device is used for controlling compressor frequency. The frequency control device is also used for acquiring actual measured return air temperature of the operating indoor units when number of the operating indoor units is unchanged and intaking temperature of indoor units indicating indoor load changes. Heat exchange target parameters are determined according to difference of set indoor temperature and actual measured return air temperature. Actual measured heat exchange parameters corresponding to the heat exchange target parameters are acquired, and the difference of the actual measured heat exchange parameters and the heat exchange target parameters is applied to a preset frequency control function to control the frequency of the compressors. By the system and the method, frequency control precision under refrigerating work conditions can be increased.

Description

technical field [0001] The invention relates to the control technology of frequency conversion multi-connection heat pump system, in particular to a load self-adaptive frequency conversion multi-connection heat pump system and a method for controlling the frequency of compressors. Background technique [0002] Frequency conversion multi-connected heat pump system is a complex refrigeration system with complex structure, huge system, highly coupled internal parameters, and various boundary conditions. [0003] figure 1 It is a structural schematic diagram of the existing frequency conversion multi-connected heat pump system. Such as figure 1 As shown, the frequency conversion multi-connected heat pump system generally consists of one or more outdoor units 01, one or more indoor units 02, central control network (CS-NET) device 03, refrigerant pipeline 04, one or more The branch pipe 05 and the communication line 06 are composed. A plurality of outdoor units 01 form an out...

AI Technical Summary

Problems solved by technology

However, when a single indoor cooling and heating load changes, the existing method of controlling the frequency of the compressor, because the actual temperature parameters of the indoor unit are not reflected in the control strategy of the compressor cooling frequency Fc during cooling, so that the compressor cooling frequency The control accuracy is not high, resulting in relatively low compressor volumetric efficiency and system energy efficiency; and when heating, the maximum value of the target exhaust pressure Pdomax has only three levels of values, and the control accuracy is also low

[0031] Furthermore, in the actual operation of the frequency conversion multi-connected heat pump system, the probability of running 100% load is relatively small. The machine operates in the middle and low frequency range to achieve a smaller compression ratio, so as to ensure that the volumetric efficiency of the compressor and the energy efficiency of the system are relatively high. However, the existing compressor frequency control method cannot quickly and accurately adjust the compressor when the load changes. Frequency to control the refrigerant flow rate, so as to achieve the purpose of load self-adaptation

Images