Design and analysis of a high frequency DC-DC converters for fuel cell and super-capacitor used in electrical vehicle

摘要

This work focuses on the application of the high frequency DC-DC converters used in electric vehicles. Two converters are necessary. The first converter is interposed between the fuel cell and the DC-AC inverter. It is unidirectional. The second one is used as interface between the ultra-capacitor and the DC-AC inverter. It allows the bidirectional of the power transfer. Each converter is composed of two full bridges, LC resonant filter and two planar transformers. The use of high frequency transformer allows to minimize the size and weight of the converter, produce a higher voltage in secondary side from input voltage (fuel cell or super-capacitor) and isolate the full bridges. The control strategy of the converters is the phase shift. The converters have been designed, realised and controlled by an FPGA board. To demonstrate the converters feasibility, two converters are implemented and tested. The switching frequency of two converters is 20 kHz. The first converter has a 24-V input and 200 V/1.2 kW output. But, the second converter has a 12.5-V input and 100 V/400 W output.