Leakage Current Reduction in a Single-Phase Bidirectional AC–DC Full-Bridge Inverter

The leakage current in grid-interface converter systems presents a considerable issue in regard to safety and efficiency. The full-bridge inverter is a well-accepted topology in single-phase power conversion applications. The high-frequency pulsewidth modulation (PWM) modulation schemes are normally applied to the full-bridge topology for smaller ac filter size, which, however, generates a high-frequency dc-side leakage current, resulting in an enormous negative impact on dc components, such as photovoltaic panels and energy storage elements. In this paper, a modified full-bridge inverter topology to reduce the dc-side leakage current as well as to mitigate the ac-side common-mode electromagnetic interference noise is presented. Several considerations are discussed, such as the PWM modulation and filter design. Compared to the other existing methods, the proposed solution provides a reliable performance for bidirectional operation, minimum additional components, low cost, and a simple design process.