Based on the research status of the topology of five-level high-voltage grid-connected inverter

a five-level neutral-point-clamped(5L-NPC)inverter topology with flying-capacitor auxiliary arm is proposed

and the self-balancing of neutral-point is realized by flying-capacitor technology. The proposed converter can be used as a high-power grid-connected inverter or a static synchronous compensator(STATCOM)in the 10 kV wind power conversion system and photovoltaic power generation system. Firstly

the causes of unbalancing problem of the three neutral points in a conventional 5L-NPC inverter are analyzed. Then

the self-balancing principle of the neutral-point by using the flying-capacitor technology is explained in detail

and the selection range of the relevant parameters is given. Finally

the correctness and feasibility of the proposed topology are verified.