Analytical Model of an Active-Clamp Bidirectional Flyback based on GaN Devices and Optimized Synchronous Operation

This study explores optimized synchronous operation with active clamps for the Multi-cell Multi-port Bidirectional Flyback (M2BF) configuration in response to the increasing popularity of multi-port structures in power electronic converters driven by renewable energy and electrical storage systems. Integrating active clamps in each cell enables Zero-Voltage Switching (ZVS) operation, reducing switching losses and third quadrant conduction losses, especially crucial for Gallium Nitride (GaN) semiconductors. In this work, analytical models describing M2BF with Active Clamp Bidirectional Flyback (ACBF) converter behavior were developed and experimentally validated, exploring the impact of leakage inductance on converter performance. The analysis highlights the substantial influence of leakage inductance on clamp capacitor voltage and the primary main power device’s drain-to-source voltage. The design parameters are analyzed to achieve the optimal balance of power losses. Emphasis is placed on optimizing the turn-off delay (x) for GaN devices, achieving high efficiency (120 W output power). Experimental validation using a GaN-based prototype confirms the efficacy of the proposed methodology.