| Recently,vehicles based on different kinds of clean energy,especially electric vehicles(EV),have aroused general attention due to the fact that EVs lead to less pollution and save fossil fuel.However,lack of charging technology prevents EVs from popularization.EVs now charge through external charging station or internal on-board charger.For the charging station,space and price are highly demanded.On-board charger can solve the problem of insufficient infrastructure,but efficiency and power density should reach a high level.This paper focuses on the integrated on-board charger system,three-phase interleaved topology is chosen for the main circuit and researches about operating principles,control strategy,modelling and simulation are carried out.A novel optimum design method for parameters in converters is presented.Based on this method,design of integrated on-board charger system is completed.Firstly,operating principles of integrated charger system with three-phase interleaved topology are analyzed,as well as the advantage for interleaved structure that the input current ripple decreases dramatically;The dynamic model of system is established using the method of small signal which can also be used to study the control strategy for interleaved converter;Simulations of Boost mode and charging mode are conducted in the software PLECS and MATLAB/Simulink respectively and experiments are carried out to validate the control strategy.Secondly,in order to ensure that the system has both high efficiency and high power density,a method is presented to design the significant parameters in the main circuit.The advantages of analytical formulas and algorithms are combined so that losses and volume are expressed in analytical formulas in the al gorithm;Especially,power inductors are studied,including the core material,design process and loss analysis.Based on iteration,the algorithm is realized to get the optimized inductance and switching frequency.Lastly,the integrated charger system is designed according to the discussed topology and optimized parameters.Based on the analysis and simulation results,the power devices,power inductors and output capacitor are designed;Furthermore,the dynamic response in Boost mode and the power qualit y of grid side in charging mode is highlighted;The system losses and efficiency of two modes are calculated by importing SPICE model of power devices to the software LTSpice.Experiments are carried out to test the chosen power devices. |
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