Comparison of Updated Soft Switched Full Bridge Converter Using Voltage-Doubler-Type Rectifier with Existing Techniques

摘要

An updated soft switched full bridge converter with voltage doubler type rectifier is proposed to reduce the circulating loss in primary and the voltage stress in secondary. The conventional converter is having the drawbacks such as circulating loss in the primary, voltage spike across the rectifier diode. Also the conventional system is using large output inductor in the secondary side; because of this core loss occurs. In this paper we introduce a new technique to overcome the above said drawbacks. Without an auxiliary circuit, zero - voltage switching (for leading - leg switches) and zero - current switching (for lagging - leg switches) are achieved in the entire operating range, which reduces the circulating loss in the primary side. To implement the converter without an additional inductor, the leakage inductance of the transformer is utilized as the resonant inductor. The resonance between the leakage inductance of the transformer and the rectifier capacitor can reduce the current stresses of the rectifier diodes and the conduction losses. The clamp diode is used to clamp the voltage spike across the rectifier diode which reduces the voltage stress of the rectifier diode. Due to its many advantages this converter is attractive for high voltage and high power applications. The analysis and design considerations of the proposed converter are presented. The simulation results confirm efficiency above 98% which is 3% to 5% more than the conventional converters.