Research And Design Of Rectification/Inverter Bidirectional Converter In Bidirectional OBC

With the development of science and technology,the demand for energy is becoming more and more large.More and more people pay attention to the gradual exhaustion of fossil fuels and the pollution of the traditional fuel vehicles to the environment.The electric energy used by electric vehicles can be obtained through renewable energy,so it attracts attention widely and is popularized all over the world.Electric vehicle On Board Charger(OBC)is responsible for converting power grid AC power into DC power to recharge electric vehicle,and its performance has a very important influence on electric vehicle and power grid.The power factor is the first consideration of OBC.The high power factor is of great significance for the efficient utilization of electric power and the improvement of the power quality.Therefore,it is very necessary to study the OBC power factor correction technology.However,with the increase of functional demand,it is also required that OBC can transform the DC power of electric vehicle battery to AC power for the use of AC electric appliances.Therefore,the research of bidirectional OBC(Bi-OBC)has strong engineering application value and practical market prospect.On the basis of extensive reading of relevant references and research results,this paper aims at the Bi-OBC application of electric vehicles,and studies its pre stage bidirectional AC-DC circuit.The topology,working principle and control mode of the common power factor correction circuit and the inverter circuit are introduced and compared in this paper.The single phase bidirectional full bridge converter is studied for the Bi-OBC.The circuit topology is a full bridge structure.It's AC side is connected with the differential mode inductor and its DC side is connected to the output filter capacitors.When it is charging,equivalent circuit topology is bridgeless PFC rectifier for power factor correction.When it works as reverse operation,circuit topology is equivalent to the single-phase voltage type full bridge inverter with unipolar frequency doubling modulation mode.The DC power of electric vehicle battery is transferred into AC power.In this paper,the working principle of two working states of the single phase bidirectional full bridge converter is analyzed,and the parameters of the main circuit are optimized.Through accurate circuit modeling,the transfer function of the circuit is calculated.Different modulation strategies and control schemes are compared,and the compensation parameters of the control loop are designed based on the precise model of the circuit.The rationality of the circuit design parameters and the control scheme is verified by Simulink simulation.At last,a 3.3kW experimental prototype is made according to the parameters of the design.The prototype adopts the Infineon high performance controller TC233 to realize all digital control.The circuit has the advantages of simple structure,few components,strong adaptability and easy expansion.The experiment tested the circuit performance of different input conditions and different loads.The experimental data further proved the feasibility of the circuit scheme.This paper provides a solution for the design of the Bi-OBC of electric vehicle.