Research On Battery Management And Control System Of Electric Driver-training Vehicle

In order to response the country's support to new energy industry,and solve the problems of high fuel and serious emissions,more and more fuel driver-training cars are transformed into electric driver-training vehicles.Similar to the new energy vehicles,the key of electric driver-training vehicles is the battery management system.In actual operations,the electric driver-training vehicles have frequent start,acceleration and ascent,also have frequent deceleration,downhill,and braking.The high current of motors' DC bus side seriously affects the lives of the batteries.Therefore,research on the battery management and control system for electric driver-training vehicles,has important significance on new energy and driving-training industry.Based on the independent power supply of batteries,the super-capacitors are joined to form hybrid energy.The bidirectional DC/DC converter is designed to realize the condition monitoring and control for battery management system of electric driver-training vehicles.Then the short and high currents of batteries are prevented.And the service life are prolonged.The main work are summarized as follows:(1)Selection of topological structure and analysis of the feasibilityBy analyzing different bidirectional DC/DC converters,the bidirectional half-bridge Buck/Boost converter is selected as the main topology for battery management system of electric driver-training vehicles.The feasibility,the operational patterns and the work principles in the two states are analyzed.(2)Establishment of system model and design of controllerAfter the advantages and disadvantages of three super-capacitor circuit equivalent models are analyzed comparatively,the one-order nonlinear model is chosen.And the charge and discharge characteristics of super-capacitors are simulated.By using state-space average method,the mathematical models of Buck and Boost states are established.Then the two transfer functions from duty cycle to inductor current are deduced.Choosing suitable PI parameters,two independent PI controllers are designed.And the closed-loop control of the system is achieved,the steady-state precision and dynamic performance are improved.(3)Design on the hardware and software of the systemAccording to the system requirements,the hardware and software design of the battery management and control system for electric driver-training vehicles are finished.Using DSP TMS320F28335 as the main control chip,the main circuit,drive circuits,sampling circuits,protection circuits and auxiliary power supply circuits are designed.And the key parameters of the main circuit are calculated.Under the CCS development environment,the software design is completed,including the design for main program,interrupt service subroutines,PI control subroutines,and so on.(4)Simulation and experimental verificationThe simulation models under three operational patterns are built in MATLAB/Simulink.And according to the design of hardware and software,the experiment platform is established to verify experimentally.The simulation and experimental results respect that the inductor current can track given current constantly in three patterns,and it has definite anti-interference ability when the load is changed,the effectiveness of PI closed-loop control is verified.The experimental data respects the energy transfer between super-capacitors and DC bus side is realized,the high current problem of batteries is solved.