Research On Bidirectional Converter For Hybrid Electric Vehicle

As the energy crisis and the pressure for environmental protection,the development of new energy vehicles is considerable.In view of the actual demand of hybrid electric vehicles,a bidirectional converter with high power density,high efficiency,safe isolation and low current ripple is studied.The bi-directional converter mainly consists of bidirectional DC-DC converter,threephase rectifier and three-phase inverter.Based on the analysis of the current demand for HEVs,the overall scheme of the bi-directional converter is designed.Aiming at the hybrid control active clamp current source half-bridge bidirectional DCDC converter,based on the analysis of its working principle,modified soft-start control strategies is proposed to improve its startup performance.Simulation results show that the improved DC-DC converter has the characteristics of high efficiency,safe isolation,low current ripple and small starting current.The mathematic model of three-phase three-leg rectifier is established.Through simulation research,the control strategy and modulation are optimized.The simulation results show that the output of the three-phase three-leg rectifier has small DC fluctuation.A novel diode clamped multilevel inverter is proposed,and its mathematical model is established.Through simulation research,an optimized compensation and control strategy for balancing the voltages of capacitors is obtained.The simulation results show that compared with the output of three-phase three-leg inverter,the proposed multi-level inverter has the advantages of low harmonic content,good electromagnetic compatibility,low switching loss,and wide inverse frequency band.In order to verify the feasibility of theoretical research,the main circuit,driver circuit and sampling circuit of bidirectional DC-DC converter,three-phase three-leg rectifier rectifier and multi-level inverter,and control board are developed,and the corresponding control software is programed.Then the development and debugging of the prototype are completed.And the experimental research is carried out.The experimental results verify the correctness of theoretical analysis and simulation design,and the viability of the proposed schemes and designs.