With the unbalance load increasing in the distribution network

the network loss raises and the key equipment may become overcurrent even damage. For this problem the unbalance load control strategy of TNPC parallel static synchronous compensator is presented. Because of the efficiency and flexibility

parallel three level converter is the efficient solution for unbalance load in distribution network. For the unbalance load and TNPC parallel system

the equivalent model of TNPC parallel circulating current is established

and the zero sequence circulating current characteristic is analyzed. According to the zero sequence voltage injection modulation

the zero sequence circulating current is controlled. Then the DC neutral balance is controlled with modulation waveform decomposition

the zero sequence current and neutral point balance decoupling control parallel static synchronous compensator under unbalanced load is realized. Finally

the experimental platform of TNPC parallel STATCOM is built to verify the effectiveness of the coordination control strategy.