Research On Integrated Control Strategy Of Variable Capacitance Tuning And Parameter Dynamic Tracking Of Magnetically Coupled Resonant Wireless Power Transfer System

Wireless Power Transfer(WPT)refers to the use of magnetic field,electric field,electromagnetic wave and other media for non-contact power transmission technology,which provides a more convenient and environmentally friendly energy transmission method for the innovation and development of various industries.However,in practical applications,the relative position change between the two coupling coils of the WPT system will change the system parameters,resulting in the system being in a detuned state and reducing the power transfer efficiency.In addition,the output voltage of a WPT system is easily affected by changes in parameters such as coupling coefficient and load resistance.In order to solve the above problems,this paper mainly studies the variable capacitor tuning control strategy of Magnatically-Coupled Resonant Wireless Power Transfer(MCR-WPT)system and the load output constant voltage control method based on parameter dynamic tracking.Aiming at the problem of system detuning,a variable capacitor tuning control strategy is proposed,which makes the capacitor equivalent to a variable capacitor by controlling the charge and discharge time of the capacitor,and then makes the equivalent capacitance value and the coil inductive reactance value meet the resonance conditions,so that the system is always in a resonant state,which can make the transmission efficiency between the transmitting coil and the receiving coil of the system reach the highest.The Matlab/Simulink simulation model is established,and the simulation results show that the variable capacitor tuning control strategy can effectively solve the system detuning problem.Aiming at the problem of system output voltage instability,a coupling coefficient estimation method is proposed,and the DC/DC converter is used to achieve the equivalent substitution of the load,so that the equivalent load reaches an optimal value,the dynamic tracking of parameters based on load matching is realized,and the constant voltage control of the load output voltage at the receiving end is realized through the phase shift control of the full-bridge inverter circuit at the transmitting end.The Matlab/Simulink simulation model of MCR-WPT system is established,and the simulation results show that the closed-loop system of constant voltage control can keep the load output voltage constant when the coupling coefficient and load resistance change under the condition of setting the output voltage value,which proves the effectiveness of the proposed control strategy.An experimental prototype of MCR-WPT system based on series-series resonance compensation topology was built,and tuning control and phase shift voltage stabilization control experiments were carried out.The experimental results show that the prototype can realize wireless power transfer with a resonant frequency of 100 kHz and an input voltage of 20V.On this basis,the variable capacitor tuning control experiment and the closed-loop constant voltage output control experiment are carried out,and the experimental results are consistent with the simulation results,which proves the effectiveness of the variable capacitor tuning control strategy and the closed-loop constant voltage output control method.