Contact Us

Leakage Current Reduction in Single-phase Bi-directional ac-dc Full-Bridge Inverter

Fig. 1. Modified 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 PWM modulation schemes are normally applied to the full-bridge topology because of its smaller ac filter size. This generates a high-frequency dc-side leakage current resulting in an enormous negative impact on dc components, such as photovoltaic (PV) panels and energy storage elements. In this nugget, a modified full-bridge inverter topology to reduce the dc-side leakage current as well as to mitigate the ac-side CM electromagnetic interference (EMI) noise is proposed with detailed design procedures. Compared to the other existing methods, the proposed solution provides a reliable performance for bi-directional operation, minimum additional components, low cost, and a simple design process.

Fig. 2. Leakage current level by using the typical full-bridge inverter (upper waveform, [5A/DIV]) and the modified full-bridge inverter (lower waveform, [5mA/DIV]).