An unloading adjustment control method for a large-displacement frequency conversion multi-connection system

Abstract

The invention discloses an unloading adjustment control method of a large-displacement variable-frequency multi-split air conditioner system. The multi-split air conditioner system involves an outdoorunit and a plurality of indoor units, wherein each indoor unit comprises an indoor heat exchanger and an electronic expansion valve, the outdoor unit comprises an outdoor heat exchanger, a compressorand an unloading electromagnetic valve, and the unloading electromagnetic valve is used for enabling an air outlet side of the compressor to communicate with an air return side of the compressor. Thecontrol method comprises the steps that the multi-split air conditioner system enters a working mode, the starting-stopping states of all the indoor heat exchangers are detected and judged; if the working mode is the refrigerating mode, outlet temperature parameters of the indoor heat exchangers in the starting states are obtained, an outlet temperature average value is calculated, and the opening degree of the unloading electromagnetic valve is determined according to the outlet temperature average value; and if the working mode is the heating mode, the middle temperature parameters of the indoor heat exchangers in the starting states are obtained, a middle temperature average value is calculated, and the opening degree of the unloading electromagnetic valve is determined according to the middle temperature average value.

Description

technical field [0001] The invention relates to the technical field of multi-connected air conditioners, in particular to an unloading adjustment control method of a large-displacement variable-frequency multi-connected system. Background technique [0002] In the current multi-connected system, the model of the indoor unit is small, and the required cooling capacity is small, and even if the inverter compressor with large displacement operates at the lowest operating frequency, its output capacity is far greater than the demand of the indoor unit (for example, 20 HP The frequency conversion compressor runs at a minimum of 10Hz, and its compressor capacity exceeds 3000W), resulting in a contradiction between large compressor capacity and small demand for indoor unit capacity, that is, the phenomenon of "big horses and small carts". When the output is large, but the evaporator of the indoor unit is small and the caliber of the matching electronic expansion valve is also small...

AI Technical Summary

Problems solved by technology

[0002] In the current multi-connected system, the model of the indoor unit is small, and the required cooling capacity is small, and even if the inverter compressor with large displacement operates at the lowest operating frequency, its output capacity is far greater than the demand of the indoor unit (for example, 20 HP The frequency conversion compressor runs at a minimum of 10Hz, and its compressor capacity exceeds 3000W), resulting in a contradiction between large compressor capacity and small demand for indoor unit capacity, that is, the phenomenon of "big horses and small carts". When the output is large, but the evaporator of the indoor unit is small and the caliber of the matching electronic expansion valve is also small, the small caliber of the electronic expansion valve will frequently cause the high pressure of the multi-connected system to overshoot, resulting in the frequent start-up of the multi-connected system due to pressure protection. stop;

[0003] At the same time, in the cooling mode, the heat exchanger of the indoor unit cannot completely evaporate the liquid refrigerant, which will cause the evaporation temperature of the refrigerant to be very low, and eventually cause the heat exchanger of the indoor unit to be severely frosted and freeze. The anti-freeze protection of the indoor unit makes The indoor unit cannot continue to cool down, causing the ambient temperature on the indoor side to change greatly, which ultimately affects the comfort of users;

[0004] In the heating mode, if the heat exchanger of the indoor unit cannot condense completely, the condensation temperature of the refrigerant will be very high, and the indoor unit will be protected against high temperature. The temperature changes greatly, which ultimately affects the comfort of the user

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