Three-Phase Isolated Boost DC-DC Converter for High Voltage Applications

The voltage fed DC-DC converter has been suffering from problems associated with large transformer leakage inductance due to high transformer turn ratio when it is applied to low-voltage, high-current step-up application such as fuel cells. This paper proposes a new three-phase voltage fed DC-DC converter, which is suitable for high-voltage, high-current applications. The transformer turn ratio is reduced to half owing to Δ-Y connection. The zero-voltage and zero-current switches (ZVZCS) for all switches are achieved over wide load range without affecting effective duty cycle. A clamp circuit not only clamps the surge voltage but also reduces the circulation current flowing in the high-current side, resulting in significantly reduced conduction losses. The duty cycle loss can also be compensated by operation of the clamp switch.The detailed design and operating principles are described and simulated using Pspice. The proposed converter is very attractive for electrolyser application