Research And Design The Optimal Control System Of Electric Vehicle Wireless Charging

Development of electric vehicle is demand for power saving, environmental protection and low carbon economy. Electric vehicle charging is essential. A convenient wireless charging technology of electric vehicle is given by this thesis which achieves non-physical contact connection of charging system and electric vehicle. It is not only improves the safety of charging systems, but also extends battery life. Optimization control technology of the battery charge and discharge process can make the battery charge and discharge process of electric vehicle faster, more stable and more efficient.The wireless power transmission system for electric vehicle is studied and coupling coil is analyzed in this thesis. Then, mathematical model of coupling coils of wireless power transmission system is established and its correctness is verified the by the experimental result of the model. Meanwhile, different methods of charging batteries are analyzed, which lay the foundation for design of battery charge and discharge control system. Then, charging scheme based on PWM pulse and the constant voltage is given, which has the characteristics of easy to implement charging, short charging time and low power consumption.Different types of rectifier circuit and DC/DC circuit are studied, single-phase bridge rectifier circuit and staggered Buck/Boost bi-directional three-phase power converter are confirmed. Then, workflow of battery charge and discharge control system is analyzed deeply and the mathematical model of DC/DC converter is established by states average space method. At last, control scheme based on double closed-loop PI current and voltage is proposed.The DC/DC converter circuit is set up in Matlab/Simulink, which enables double closed-loop PI control system of battery charge and discharge through the battery charging procedure. Simulation results show that PI control strategy and three-phase interleaved technical have advantages.In the DC/DC converter of nonlinear and variable structure, battery charge control system is optimized bases on double closed-loop PI algorithm, and then PI control and combined control strategy of variable structure control of slide film is given in this thesis. Experimental results show that the algorithm can improve the accuracy of control system, dynamic performance and adaptive capacity.