An RCDD snubber for a bidirectional flyback converter

Increased usage of renewable energy sources has boosted the demand for power electronics converters. Indeed, the DC/DC flyback converter is nowadays frequently used in applications where isolation is required, due to its low component count, simple structure and high energy efficiency. One of the major challenges faced in a flyback converter is the excess voltage stress sensed by its semiconductor devices, because of the interrupted current flow through its transformer leakage inductances. In this paper, a high-efficient bidirectional flyback converter, operating in discontinuous conduction mode, is examined with an integrated RCDD snubber. Additionally, experimental comparison where the converter runs with a typical RCD and RCDD snubber network, is done. Experimental results on an IGBT-based bidirectional flyback converter validate the applicability of the RCDD snubber demonstrating energy efficiency above 90%. Furthermore, the operation of the bidirectional converter with the employed snubber is thoroughly analysed and an appropriate mathematical analysis is conducted highlighting all the design specifications of the proposed snubber.