A zero-voltage and zero-current switching full bridge DC-DC converter withtransformer isolation

A new primary-side-assisted zero-voltage and zero-current switching full br idge de-dc converter with transformer isolation is proposed. The proposed d e-de converter uses only one auxiliary transformer and two diodes to obtain ZCS for the leading leg. It has a simple and robust structure, and load cu rrent control capability even in short circuit conditions. Possibility of m agnetic saturation due to asymmetricity of circuits or transient phenomena is greatly reduced, which is a very attractive feature in dc-dc converters with transformer isolation. The power rating of the auxiliary transformer i s about 10% of that of the main transformer. Operation of a 12 KW prototype designed for welding application was verified by experiments.