Adaptively modulated multi-state inverter system and modulating method thereof

An adaptively modulated multi-state inverter system, comprising:

• a split capacitor, a first bridge arm, a second bridge arm, a third bridge arm, a fourth bridge arm and an isolation switch;
• wherein on each of the first, second and third bridge arms a pair of complementary power switch groups is arranged;
• the isolation switch group comprises a first fuse, a second fuse, a third fuse and a fourth fuse as well as a first bidirectional thyristor, a second bidirectional thyristor, a third bidirectional thyristor, a fourth bidirectional thyristor, a fifth bidirectional thyristor and a sixth bidirectional thyristor;
• on each output branch of the first bridge arm, the second bridge arm, and the third bridge arm, a corresponding one of the first fuse, the second fuse and the third fuse is connected in series such that the output branches of the first, second and third bridge arms output a three-phase voltage, and at a three-phase output voltage side a first shared auxiliary branch and a second shared auxiliary branch are arranged;
• the first auxiliary branch starts from an output branch of the fourth bridge arm, on which output branch the fourth fuse is connected and is then connected to an output terminal of the three-phase voltage via the first, second and third bidirectional thyristors respectively;
• the second auxiliary branches starts from a DC side feed branch from a midpoint of the split capacitor, and is connected to the output terminal of the three-phase voltage via the fourth, fifth, and sixth bidirectional thyristors respectively.