An Optimal Control Strategy for Single-Stage Dual-Bridge Series Resonant Microinverters

The single-stage dual-bridge series resonant converter (DBSRC) is gaining prominence in microinverter applications due to its straightforward design, minimal component requirements, and high efficiency. However, enhancing the efficiency of microinverters using the DBSRC topology presents challenges, including its extensive control complexity, variable voltage conversion ratios, and fluctuating load conditions. This paper introduces a novel control strategy that optimizes efficiency in real-time by fully leveraging phase-shift and frequency control capabilities. We present a closed-form analytical solution designed to maximize efficiency by minimizing RMS current under zero-voltage switching (ZVS) conditions. The effectiveness of our proposed control strategy is demonstrated on a 500-W microinverter platform.