Modeling And Control Of MCR-WPT System With Additional DC/DC Control

Magnetic coupled resonant wireless power transmission(MCR-WPT)has been widely used due to its advantages of long transmission distance and high transmission efficiency.In the application of MCR-WPT system,there are two important problems: one is to make the output voltage and/or current meet the load demand in the dynamic process;the other is to make the system maintain the maximum efficiency while meeting the load voltage and current requirements.The MCR-WPT system with DC/DC control can control the output voltage and current,and keep the resonant state of the system without destroying the ZVS condition of the inverter switches.Therefore,this paper studies the modeling and control of MCR-WPT system with additional DC/DC control,and further studies the maximum efficiency tracking problem under the condition of output control.Accurate mathematical model is the basis of system analysis and design.The MCR-WPT cell is a high-order nonlinear circuit.Aiming at the MCR-WPT cell,the steady-state mathematical model is established to find the variables that control the output voltage and current,which provides theoretical support for the design of constant voltage or constant current output control scheme.Then,the dynamic mathematical model is established based on the generalized state space average method,and the accuracy of the model is verified.Further,the model is reduced to provide a basis for simplifying the design of controller and parameters.For the MCR-WPT control system with DC/DC in the front stage,the dynamic mathematical model of the controlled object is established based on the dynamic model of MCR-WPT unit.On this basis,the structure of constant voltage control system and constant current control system is studied.The design process of constant voltage controller and constant current controller is given systematically.Then the control effect of the designed controller under the system parameter disturbance is verified by simulation.For the MCR-WPT control system with DC/DC in the later stage,firstly,the dynamic mathematical model of the controlled object is established.Based on the dynamic model,the structure of constant voltage control system and constant current control system is studied,and the corresponding controller is designed.Then,the anti-interference ability of the designed controller is verified by simulation.Aiming at the problem of maximum efficiency tracking under constant voltage control,the steady-state mathematical model of closed-loop control system is established,and the transmission efficiency of two kinds of MCR-WPT constant voltage control system with DC/DC is studied,and the conditions for the system to reach the maximum transmission efficiency point are found.Based on this,two maximum efficiency tracking control schemes with DC/DC in front and back are proposed under constant voltage control.The constant voltage controller is further designed,and the disturbance observation method is used to achieve maximum efficiency tracking.Finally,the system simulation model is established,and the effectiveness of the design scheme is fully verified by the simulation results.