A low-voltage protection method for rail vehicle air-conditioning units

Abstract

The invention discloses a low-pressure protection method for a rail vehicle air-conditioning unit, which belongs to the technical field of rail vehicle air-conditioning equipment, and is based on a rail vehicle air-conditioning unit with a low-pressure pressure protection switch and a low-pressure pressure sensor or an evaporation temperature sensor, including pressure drop load entering steps and The step of pressure drop and load exit, the step of pressure drop and load entry includes: real-time detection of low pressure or evaporation temperature, if the detection of low pressure LP ≤ LP1 or evaporation temperature T ≤ T1 and the duration of t1, open the bypass solenoid valve; pressure drop and load exit The steps include: if it is detected that the low pressure LP ≥ LP2 or the evaporation temperature T ≥ T2 for a duration of t2, and at the same time the bypass solenoid valve has been opened for not less than 3 minutes, allowing the bypass solenoid valve to be closed. The present invention advances the low-voltage protection measures of the air-conditioning system before low-voltage faults occur through unloading start-up automatic control and pressure drop-load automatic control by combining software and hardware, and can significantly reduce the failure rate of system low-voltage protection.

Description

technical field [0001] The invention belongs to the technical field of rail vehicle air-conditioning equipment, and in particular relates to a low-voltage protection method for rail vehicle air-conditioning units. Background technique [0002] Most of the air-conditioning units currently used in rail vehicles are still fixed-frequency air conditioners. The low-voltage protection method mainly uses software to record the number of action protection times of the low-voltage switch, fault lockout, and fault reset to realize the low-voltage protection of the refrigeration system. [0003] In the transitional season of spring and autumn when the external temperature is low, the set temperature inside the car is low and / or the air supply volume is too small due to the dirty filter of the air conditioner, so that the evaporation temperature of the air conditioner unit is lower than the freezing point of water, and the evaporator freezes. Frost, and then the low pressure switch acti...

AI Technical Summary

Problems solved by technology

[0004] Since the existing low-voltage protection method can only try to avoid the system being locked by the low-voltage protection, the protection is based on the fact that the low-voltage switch has already operated, and there is no predictive automatic control of the operation of the refrigeration system to adjust in advance to avoid The low-pressure switch is activated. At this time, the refrigeration system may have frosted and sprayed water, or the system cannot be prevented from being locked by the low-pressure protection in the end.

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