Design And Develop Of MH-Ni Battery Management System For Hybird Electric Vehicle

As the world’s energy problems become increasingly serious and national measures to protect the environment are more stringent,the development and utilization of electric vehicles have drawn more and more attention.But for electricity-only vehicles with a single battery power source,the development of these electric vehicles is slow,because their mileage endurance is far less than that of traditional cars,the cost of the entire battery pack system is high,and charging time is long.Hybrid vehicles have lower fuel consumption and emissions than that of traditional cars,and production cost is lower than that of pure electric vehicles,but they are close to traditional cars in terms of power and mileage.Thus,they have been the focus and hotspot in recent years and have begun commercialization.Battery management system is one of the core components of hybrid cars,and is the connection link between battery and the whole vehicle.In this paper,under the support of the National 863 Project,the research on the nickel-metal hydride battery management system of hybrid electric vehicle is carried out.The main research work is as follows:1.Based on the study of the characteristics of NiMH batteries and the balance of complexity and calculation accuracy of NiMH batteries,the Ni-MH battery is modeled by the second-order RC equivalent circuits,and real-time battery model parameters are identificated by using the improved recursive least squares algorithm.The algorithm is validated through the experimental platform and real-time embedded system.2.In order to obtain the real-time estimation of the rest power of Ni-MH battery,an estimation algorithm based on improved Extended Kalman Filter(EKF)and on-line parameter identification with SOC is proposed.The algorithm first uses the on-line identification to update the model parameters and then starts the improved EKF for SOC estimation.The experimental results show that the algorithm has higher accuracy and robustness than the commonly used Ah integral method.3.Designed a hybrid vehicle with nickel-metal hydride battery management system using a distributed topology based on the CAN bus.Introduced overall design of the system hardware circuit.The hardware design of Battery Mangment Unit(BMU),Battery Temperature Unit(BTU)and Battery Control Unit(BCU)is described in detail,and the relevant hardware schematic is given,while the single voltage,temperature,bus voltage,current,CAN communication,relay control and other functions are achieved.4.Developed a nickel-metal hydride battery management software system of hybrid vehicles,and the design and implementation of BMU,BTU and BCU module software are introduced.In order to facilitate the debugging and maintenance of entire battery management system respectively,the battery management system PC monitoring software,Canbootloader PC software and automated calibration software are developed for comprehensive testing of the entire battery management system.At present,the nickel-metal hydride battery management system is running on the test prototype vehicles with a good performance.