AC and DC isolation inverter technology: DC system uses high frequency and high efficiency DC isolation converter, so that the input and output electrical isolation, effectively prevent electric shock accidents, make the DC system grounding problem very simple, and the two grounding is more convenient. The active filter technology used in DC greatly reduces the noise of the system and improves the input voltage of the DC system. The DC/DC high frequency isolation converter is connected to the inverter with high voltage and APFC high voltage in parallel. So when the power supply is normal, the inverter is supplied by AC rectifier and the DC is in the state of hot backup. When the power interruption or abnormal AC input, protect the normal startup, DC isolated by the DC/DC transform to the inverter power supply, inverter into 220V sine wave output voltage, so whether it is normal or not, the power supply system is through the inverter power supply to the load, so it is always the output AC voltage and frequency stabilization the voltage of 220V, realize the uninterrupted work.