Research And Implementation Of Battery Management Unit Base On Plug-In Electric Vehicles

Soaring oil prices, a shortage of oil supply and the increasingly seriousenvironmental pollution, make all people who use trade traditional fossil energy asthe main energy, gradually realize the importance of the development and use ofrenewable clean energy. New energy vehicles using secondary battery as the mainpower gradually become the focus of research and development, that all countries arein the development of a new generation of electric cars. The performance of thebattery is easily affected by environmental factors and usage, the unreasonable use ofthe battery will cause serious damage to its performance. Reasonable for batterycharge and discharge management, real-time monitoring of battery state, dealing withproblems arising while using the battery, is particularly important. In order to solvethe security problems of the battery, we need to learn related technologies,specifically for the design of a stable performance of the battery management system.According to the needs of project, the author designed the management unit ofthe battery management system. The control panel uses freescale company S12Dseries single chip microcomputer as the core. On the design of the hardware andsoftware, the system implements the battery voltage measurement, the total currentmeasurements, the battery insulation detection, high voltage distribution control, fancontrol, and the BMS system, car charger and the vehicle of communication, andother functions.On the design of SOC algorithm, first of all, the author studies the performanceof the “three yuan battery” provided in this project, analys the common batterymodel, establish the Simulink Simulation model of the battery which is verified byexperiments. Then, based on the established cell model, using kalman filter algorithmas the core, we set up the simulation model of SOC algorithm.In the SOC verificationexperiments, the author test the accuracy of the model of algorithm through theworking condition of two kinds of test.And the algorithm simulation error controledwithin5%eventually, meeting the design requirements. Finally through the RTW toolthe author automatically turns the model to generated C code which is nested to thesoftware in the main program, and completes the design of the control system of the whole.At the end of the paper, through the experiment on the control panel, theinspection precision error of voltage current detection is less than0.5%, meeting thedesign index. Insulation detection can basically distinguish the insulation condition,between good state to bad state, meeting the purpose of design.