Control method of low voltage operating fixed speed air conditioner

The present invention relates to a control method of a low voltage operation constant speed air conditioner, which is characterized in that the rotary speed of an indoor electric motor is adjustable, when the network voltage is changed, a conduction angle of a controlled silicon in a motor-drive circuit is adjusted in order to stabilize the rotary speed of the indoor electric motor, the different rotary speed shifts of an outdoor electric motor are changeable, under different ranges of the network voltage and/or different external disk temperature of the outdoor condenser, the outdoor electric motor operates on the different rotary speed shifts, controlling compressor overflowing protection, the closing down overflowing protection of the compressor is fed with the protection current value lower heat protector before the system heat protector feeds protection, and the batch restart of the compressor are completed within the setting time after feeding protection. The air conditioner of the present invention can be normal starting under 180V even under the condition of lower electric voltage and keep operation, the abnormal noise can be avoided when the electric network fluctuates, and the present invention can be active closing down protection and rapidly be automatic recovery normal running after electric voltage resumption.