Multi-split air conditioning system

Abstract

The invention relates to a multi-split air conditioning system. The multi-split air conditioning system comprises a calculation module which calculates a difference delta P between exhaust pressure Pd and suction pressure Ps of a compressor before shutdown when an outdoor unit receives a shutdown instruction of the last indoor unit in operation; and a control module which is configured to execute the following voltage-sharing control that whether delta P is larger than delta P3 is judged; when delta P is smaller than or equal to delta P3, if current frequency H of the compressor is larger than a safe frequency value H0 when the compressor is safely shut down, the compressor is shut down after frequency of the compressor is reduced to be smaller than or equal to H0, and if H is smaller than or equal to H0, the compressor is shut down; and when delta P is larger than delta P3 and a current operation mode is a refrigeration mode, first pressure difference control is carried out, and when the current operation mode is a heating mode, second pressure difference control is carried out. According to the invention, on the basis of not increasing hardware parts, pressure difference is effectively balanced, and liquid return risks and noise risks are effectively reduced.

Description

technical field [0001] The invention belongs to the technical field of air conditioning, and in particular relates to a multi-connection system. Background technique [0002] In the existing multi-line system, such as figure 1 As mentioned above, the multi-connected system includes an outdoor unit 100 and a plurality of indoor units ( figure 1 Only one indoor unit 200 is shown in the figure), and the indoor unit 200 and the outdoor unit 100 are connected through a refrigerant connection pipeline. The indoor unit 200 is provided with an indoor heat exchanger 210, an indoor fan 220, and an electronic expansion valve 230, and the outdoor unit 100 includes an outdoor heat exchanger 110, an outdoor fan 120, a compressor 130, and a four-way valve 140 connected through a refrigerant connection pipeline. , electronic expansion valve 150, and oil separator 160. [0003] After the multi-connected unit is shut down, it is necessary to balance the pressure difference of the refrigera...

AI Technical Summary

Problems solved by technology

[0008] There are two hidden dangers in the above scheme. (1) When there is no gas-liquid separator in the multi-line system and the internal unit of the condenser of the outdoor unit is small, the refrigerant is guided to the suction side of the compressor by opening the valve to equalize the pressure, and there is a start-up process. The risk of "liquid return" of the compressor; (2) The pressure equalization process of opening the electronic expansion valve 230 of the indoor unit after the cooling operation is stopped will bring about a large refrigerant flow sound

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