Variable frequency controller precharging control method

The present invention relates to the technology of air-conditioner control and discloses a variable frequency controller precharging control method to solve the problems of the device damage caused by IGBT upper and lower bridge arm direct connection caused by a traditional technical control scheme and the large fluctuation of motor current waveform caused by the charging current of a sampling resistor. The scheme of the invention comprises that before the starting of a motor, the precharging control of a variable frequency controller is carried out, before the establishment of control chip power supply voltage of an upper bridge arm, the upper bridge arm IGBT PWM wave input is prevented, and in a pre-charge time T1, only the PWM wave of a lower bridge arm IGBT is inputted. The method is applicable to frequency converter precharging control.