| Electric vehicles are more environmentally friendly and economical than traditional fuel vehicles,and have become the development direction of future automobiles.As an important power conversion device,bidirectional DC-DC converter plays a key role in driving efficiency,driving range and other performance of electric vehicles.The research object of this paper is the non-isolated bidirectional DC-DC converter in the hybrid energy storage system composed of batteries and ultracapacitors.The main research content includes the following aspects:In order to improve the efficiency of the converter and reduce the voltage and current stress of the switching tube and the ripple of the output voltage and current,the topology of two-phase interleaved bidirectional DC-DC converter is improved,a new type of two-phase interleaved soft-switching bidirectional DC-DC converter using coupled inductor topology is proposed in this paper.The topology provides an auxiliary energy loop through the leakage inductor,which provides a condition for the zero voltage opening.In this paper,the two operating modes of the topology,the realization principle and the constraint conditions of the soft switch are analyzed in detail,and the circuit parameters of the main circuit are determined.Through simulation,it is verified that the topology can realize soft switching,and codirection coupled inductor can significantly reduce the output voltage and current ripple.In this paper,a bidirectional DC-DC converter is built with TMS320F28335 DSP as the control core.Experimental data show that the converter can realize bidirectional energy flow and realize zero voltage soft switch.The converter works in Boost mode and can Boost the ultracapacitor to power the load.Working in Buck mode,the converter can reduce the voltage at the high voltage side and charge the ultracapacitor.At the same time,codirection coupled inductor can reduce the output voltage and current ripple of the converter.The feasibility of the design scheme is proved. |
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