Combined three-level AC direct converter with input and output sharing the same ground

Combined TL AC direct converter with input and output sharing the same ground combined by two AC direct converters is presented in the paper. The operation principle in steady state of the proposed converter is investigated. Voltage-united control strategy for the converter is also presented and analyzed. And key parameter design is given. The circuit topology and the feasibility of the voltage-united control strategy are well proved by experiment results.