Research On SWISS Rectifier Applied In Electric Vehicle Charging

Since the 21st century,the demand for energy is growing,which the traditional car consumed a lot of petrochemical energy.Therefore,developing the electric vehicle-based new energy vehicle technology vigorously,is the major countries and car manufacturers common strategy selection.SWISS rectifier,a high-power new DC charger,is a one-way,step-down,with a power factor correction function of the new three-phase rectifier;and with a unit power factor operation,low switching loss,low switching stress,low total harmonic distortion rate,the output bus voltage range adjustable and other excellent performance.Thus,it is very suitable for electric vehicle charging,and with a higher research value and application prospects.In this paper,the working principle and control strategy of SWISS rectifier were mainly studied.Furthermore,the virtual resistance damping control and the LC filter control strategy of the notch filter were proposed,which solved the resonance problem of the input LC filter and system oscillation.Finally,the simulation model was built and the results were analyzed in PLECS software.It shows that the relevant control strategy proposed in this paper is real and effective.Firstly,the paper introduced the principle of electric vehicle fast charge,that is,the three law of Ma Si;and elaborated SWISS rectifier working principle;in addition,designed main circuit parameters and calculated the power electronic device voltage and current stress.Then,on the basis of analyzing the working principle of SWISS rectifier,the control strategy of SWISS rectifier was introduced,and the current space vector control was emphatically elaborated.Two typical current space vector controls,the switching control strategy with the smallest amplitude of the injected current ripple and the switching control strategy with the smallest ripple of the DC bus inductor current,were emphasized.Moreover,the duty cycle of the switch in different sectors and different control strategies were calculated by mathematical derivation.Again,the paper introduced the working principle and parameter design method of LC filter briefly.It found that LC filter existed a resonant peak by drawing the bode diagram in MATLAB software,which might bring oscillation and reduce system efficiency.In order to solve this problem,the damping coefficient of the LC filter must be increased by compensation.Therefore,the thesis proposed passive damping and virtual damping control method,of which the bode diagram and advantages and disadvantages were analyzed and compared.In addition,another form of the virtual damping control method,that is,LC filter with notch filter control strategy,was introduced briefly.Finally,the simulation model of SWISS rectifier based on the PLECS software was built,and the main circuit and control circuit were described in detail.It focused on the LC filter non-damping control and virtual damping control strategies,of which steady state and dynamic work were mainly analyzed.At the same time,it also briefly analyzed the DC power supply ripple,the power loss and the system efficiency of SWISS rectifier.The simulation results show that the SWISS rectifier can express its excellent performance,and verify the virtual damping control strategy proposed in this paper is real and effective.