A Single-Phase Nonisolated Inverter With a High Attenuation Gain Magnetic-Coupled Active Filter

This article presents a single-phase nonisolated inverter with a high attenuation gain magnetic-coupled active filter, which is able to strongly attenuate switching current ripple over a wide range of switching frequency. By applying active switching voltages to the coupled main and auxiliary inductors to generate opposing currents, the magnetic flux cancellation operation is achieved, thus actively eliminating switching current ripple on the output branch at any switching frequency. The magnetic-coupled active filter's insensitivity to switching frequency makes it ideal for variable frequency operation. Notably, all components required for this filter are inherent in the inverter, and therefore no additional filter elements are required. The working principle of the proposed inverter, the ripple attenuation capability, and the design of the controller is analyzed in detail in this article. Finally, the validity of the proposed inverter and control strategy are confirmed by simulation and experimental results.