An efficient self-voltage sharing input-series output-parallel converters

This paper deals with high voltage and high power DC-DC converters in the load side of non-grid-connected wind power system. The circuit is based on input-series output-parallel (ISOP) connected DC-DC converters topology because this kind of topology reduce the large voltage stress of all switches in each module. ISOP converters composed of DC-DC transformers which are their basic modules can realize the multi-module voltage balancing and current sharing automatically. Another advantage is each module achieves soft-switching by the resonance between the transformer leakage inductor and the parasitic capacitors of switches. So, the whole converters get high efficient. The scheme is so convenient that we only need to add the number of basic modules when the input voltage increases. Every circuit parameters which possibly influence the voltage sharing are enumerated. The effect of the dynamic voltage balancing is given by the simulation and experimental results. The experimental waveforms show that this kind of ISOP converters not only achieves voltage balancing and current sharing, but also has fast response to dynamic voltage equalization.