Improved three-phase four-bridge-arm inverter

For a problem that the output voltage of a conventional three-phase inverter cannot fully compensate and a harmonic voltage distortion rate is high when a grid needs to be compensated with a very highvoltage and the grid is seriously polluted, the invention provides an improved three-phase four-bridge-arm inverter which comprises centralized control boards, driving circuits, DC voltage sources, three-phase inverter main circuits formed by four bridge arms and filtering circuits. The inverter is characterized in that a load neutral point is opened, and two ends of a three-phase load are connected to output ends of completely symmetrical three-phase four-bridge-arm inverters. Compared with the conventional inverter, the improved three-phase four-bridge-arm inverter has the advantages that the voltage amplitude of outputted by the inverter can be improved, the distortion rate of the harmonic voltage is reduced, the output quality of the voltage waveform of the entire inverter is improved, the voltage level of a