Control method suitable for universal input voltage buck-boost grid-connected inverter

The present invention discloses a control method suitable for a wide input voltage step-down grid inverter, the inverter control method of the case. The present invention is an input voltage of the feedback signal to the output voltage and the switching gate switch control signal after a specified comparison, when the gate switch control signal is low, wide input voltage for the grid-down inverter operates the lifter voltage mode, the first, second, fifth, sixth frequency switching power switch in a half line cycle, the third, the fourth power switch in the entire high-frequency switching frequency cycle; when said selected the switching control signal is high, wide input voltage for the grid-down inverter operates in the buck mode, the first, second, third, fourth power switch switching frequency, fifth, sixth power switch in a half cycle of the high frequency switching frequency. The present invention is applicable to a wide input voltage and the buck transformed grid inverter, reducing the weight and volume of the filter inductor, reducing the voltage and current stress on the power switch, improve the conversion efficiency, reduce the cost, solve the problem through the power switches of the inverter bridge leg, improving the reliability.