Protection method for abnormal power failure of indoor unit in multi-connected air-conditioning system

Abstract

The invention discloses an abnormal power-off protection method of a VRV air-conditioning system indoor unit. The abnormal power-off protection method of the VRV air-conditioning system indoor unit comprises the following steps that (1) whether a zero cross signal exists or not at present is judged, and if not, the duration time without a zero cross signal is judged; (2) whether the duration time without a zero cross signal exceeds a preset threshold value t1 or not is judged, if yes, the current operation mode of an air conditioner is judged, and an electronic expansion valve is controlled to a corresponding position according to the operation mode; and in the step (1) if an indoor unit single-chip microcomputer does not detect a zero cross signal, a power supply circuit of the indoor unit single-chip microcomputer is automatically switched to an energy storage circuit to supply power. According to the abnormal power-off protection method of the VRV air-conditioning system indoor unit, the indoor unit single-chip microcomputer judges an abnormal power-off phenomenon of the indoor unit by detecting the zero cross signal, the opening degree of the electronic expansion valve is adjusted and controlled according to the current operation mode of the air conditioner, refrigerant backflow is prevented, and an insufficient evaporation phenomenon is prevented. The arrangement of the energy storage circuit is the premise for guaranteeing that the indoor unit single-chip microcomputer can work when power is off.

Description

technical field [0001] The invention belongs to the technical field of air conditioning, and in particular relates to a protection method for abnormal power failure of an indoor unit of a multi-connected air conditioning system. Background technique [0002] As the number of indoor units that can be connected to multi-connected air conditioners increases, the assembly environment becomes more and more complex. Especially for air conditioners installed in office buildings, since the power supply of each indoor unit is independently controlled by each owner, frequent occurrences The situation where some indoor units are powered off individually; the power failure of some indoor units in a multi-split system brings about the biggest problem is that the state of the electronic expansion valve is uncertain. If the electronic expansion valve is in the open state, the refrigerant will directly flow back to the outdoor unit side at this time. , resulting in insufficient evaporation,...

AI Technical Summary

Problems solved by technology

[0005] In order to solve the problem of poor user experience or high hardware cost when dealing with abnormal power failures in the existing multi-connected air-conditioning units, the present invention proposes a protection method for abnormal power-off of indoor units of a multi-connected air-conditioning system, which can solve the above problems

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