Method for judging open circuit of power device

According to the method for judging the open circuit of the power device, the current of each phase of a three-phase motor is collected, and if the absolute value of the positive peak value of the current of the same phase is smaller than half of the absolute value of the negative peak value, the upper power device of the phase is in open circuit; if the absolute value of the positive peak value of the current of the same phase is two times greater than the absolute value of the negative peak value, the lower power device of the phase is disconnected; if the peak value absolute value of the phase with the minimum peak value absolute value is smaller than half of the peak value absolute value of the phase with the maximum peak value absolute value, the upper power device and the lower power device of the phase with the minimum peak value absolute value are both disconnected; if the peak value of any phase of current is smaller than the threshold value, the upper power device and the lower power device of at le