Research On Strategy Of Extended-range Electric Bicvcle Based On Battery Management

With the rapid development of society,the problems of energy scarcity and environmental pollution are becoming more and more serious.As this,the pressure of traditional automobile energy-saving and emission reduction continues to increase,but the development of pure electric vehicle is seriously restricted because of the battery's price,energy density and charging problem.To overcome those issues of electric vehicle,range extenders combining engine and generator are introduced to electric vehicles.The special devices are always ready to charge on-board batteries at any time,thus effectively extending the driving range.Therefore,based on some extended range electric vehicle,the circuit of the control system and its control algorithm are designed.Besides,the battery model is established and based on the model,the battery SOC is predicted with Kalman Filter Algorithm.With accurate prediction of the battery SOC,the vehicle control strategy is designed,effectively extending the battery life,and the fuel consumption was evaluated.First of all,design the overall functions of the vehicle controller hardware and select the master chip of the controller selection.With the overall function,each module circuit and the algorithm of control system are designed,including the ISG motor double closed loop control algorithm,voltage and current signal filter algorithm,step motor driven algorithm and so on.The results show that the hardware and the driver algorithm of each module can realize the corresponding function,and the circuit effectively protected.Secondly,the battery model called "Improved Rint Model" is established,and HPPC Test is done on the battery to identify the parameters,including the relationship between the open circuit voltage and the SOC,the relationship among the resistance,the current and the SOC,the relationship between the efficiency and the current.In order to eliminate the cumulative error with the current integration method,establish the state equation and observation equation and predict the SOC with Kalman Filter Algorithm.The test results show that on the conditions of steady current,the error of battery SOC prediction is less than 10%.The accuracy of the battery SOC prediction can meet the basic requirements of the vehicle control strategy.Finally,based on the accurate prediction of battery SOC value,the vehicle control strategy is innovative put forward on extended range electric vehicle.Set the upper and lower limits of battery SOC value in consideration of the fuel consumption and battery life and during the charging time,the charging current can meet the three stage of charging strategy.The control strategy is realized in the controller and fuel consumption is evaluated in this strategy.The results show that the vehicle control strategy can be realized,the battery charging meets the requirements of the three stage charging strategy and the fuel consumption can be maintained at a low level.