Control method for guaranteeing stable operation of air source heat pump at low exhaust temperature of -40 DEG C

The invention discloses a control method for guaranteeing stable operation of an air source heat pump at the low exhaust temperature of -40 DEG C, and belongs to the technical field of low-temperatureoperation. A compressor communicates with an indoor heat exchanger, an outdoor heat exchanger and an economizer, and the indoor heat exchanger communicates with the economizer. The economizer communicates with the outdoor heat exchanger. When a unit operates, the outdoor temperature is measured; if the outdoor temperature is higher than a set value, the opening degree of a main electronic expansion valve is adjusted, and the exhaust temperature is adjusted; if the outdoor temperature is not lower than 60 DEG C, the opening degree of an air supply electronic expansion valve is adjusted, and air supply is carried out on the compressor; if the outdoor temperature is lower than 60 DEG C, air supply is not carried out on the compressor, and the process is finished if the standard is met; and if the outdoor temperature is lower than the set value, the opening degree of the main electronic expansion valve and the opening degree of the air supply electronic expansion valve are adjusted, the oil temperature is judged, and the process is finished if the standard is met. According to the control method, the air source heat pump can still stably operate in the low-temperature environment of -40 DEG C, the low-temperature performance of the unit is greatly improved, and the stability of unit operation is improved; and wet compression is avoided, and the advantages of being easy to control,high in practicality, high in stability and the like are achieved.