Cycloconverter-Based Double-Ended Microinverter Topologies for Solar Photovoltaic AC Module

This paper investigates a novel half-bridge cycloconverter configuration on load side with devices operating at line frequency, thus providing direct high-frequency ac to line frequency ac conversion with transformer isolation. This paper also presents a detailed comparative study and evaluation of double-ended converters, viz., full-bridge, half-bridge, and push-pull-based microinverter topologies for solar photovoltaic ac module. Double-ended converters offer merits of no transformer saturation, reduced transformer, and filter size. Simple sinusoidal pulsewidth modulation for standalone mode and current control for grid-tied mode are implemented for front-end devices. Comparative study reveals that half-bridge topology is cheaper than the other two topologies and has comparable efficiency with full bridge. A 250-W laboratory prototype of half-bridge microinverter is developed, and experimental results are demonstrated to show its performance under various conditions, i.e., standalone, grid-tied, and change of current references.