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This paper presents a new microinverter topology that is intended for single-phase grid-connected PV systems. The proposed microinverter topology is based on a flyback converter, where an extra switch is added to separate the decoupling capacitor from the PV Module, which allows for a high voltage and voltage ripples across its terminals. This results in reducing the power decoupling required capacitance. In this manner, long life-time low power density film capacitors can be used instead of life-time limited high power density electrolytic capacitors, resulting in remarkable increase of microinverter's lifespan. The main advantages of the proposed topology are summarized as: 1) eliminating the double-frequency power ripple using a small film capacitor; 2) using long lifetime film capacitors, which will improve the reliability of the inverter; and 3) requiring no additional circuitry to manage the transformer leakage energy. A 100-W microinverter prototype was built to verify the proposed topology. Experimental results show that the proposed topology and its control scheme can realize the power decoupling, while maintaining very good conversion efficiency numbers. [ABSTRACT FROM AUTHOR]

A pulse-skipping control strategy is proposed to improve efficiency of grid-tied inverters at light loads. To maximize the efficiency of pulse-skipping operation mode, three key parameters are identified and optimized based on a loss model, which is developed to find the maximal efficiency points using a 3-D search technique. A 200-W prototype inverter was setup to verify the proposed control strategy. The experimental results show that the proposed pulse-skipping control strategy greatly improves the inverter's efficiency at light loads and match the simulation results fairly well, thus, validating the proposed optimization method for pulse-skipping operation. [ABSTRACT FROM PUBLISHER]