A high-efficiency resonant solar micro-inverter

Transmission grids worldwide are presently facing challenges in integrating large scale renewable systems due to their limited power transmission capacity. This paper presents a novel circuit topology and control for grid connected micro-inverters suitable for solar AC modules. This topology is based on the single-stage DC to AC conversion approach. The circuit has an L-C series resonant converter, a high frequency transformer and a line frequency unfolder. Design and control considerations are presented along with the detailed design of resonant components. The circuit components and controls have been optimized to achieve very high efficiency at various load and input conditions. A controller has been designed and simulated using a Simulink^® numeric package. An experimental prototype was designed to achieve a high California Energy Commission (CEC) efficiency rating.