Research On Capacitively Coupled Wireless Energy Transfer Mechanism

The emergence of wireless energy transmission technology has provided great convenience for the development of people’s life and society.Currently,the most widely used is magnetic field coupled wireless transmission,and the transmission mode has strong coaxiality of coils,large eddy current loss,high electromagnetic interference and other problems,which affect the development of this technology.Therefore,in order to solve this problem,and according to the duality of inductance and capacitance,this dissertation proposes a new type of capacitively coupled wireless transmission topology,and studies and verifies it in principle.Capacitively coupled wireless energy transmission,also known as electric field coupled wireless energy transmission,is a new transmission method that utilizes power electronic conversion technology combined with modern control theory.In this dissertation,the system topology and working principle of the new capacitive coupled wireless energy transmission are firstly described.At the same time,the extracted energy scheme existing in the topology is theoretically analyzed and deduced.Finally,the practical energy extraction scheme for wireless transmission is determined according to the engineering practice.Secondly,combined with the designed target,the parameters of the AC equivalent resistance and the parallel coupling equivalent inductance are respectively configured by the idea of control variable analysis.At the same time,the impedance spectrum characteristics,output characteristics and tuning characteristics of the selected scheme are simulated respectively by Matlab simulation,and the relevant characteristics of the topology are obtained.Aiming at the time-varying of equivalent capacitance of coupling mechanism,a dynamic tuning method based on switched capacitor array is proposed.The level difference in the switched capacitor array by setting the output voltage error.In order to avoid the parallel resonance point,the step by step testing control algorithm is used to make the system close to the resonance state,which improves the stability of the system and maximizes the energy transmitted by the system.The feasibility of this tuning method is verified under the Simulink platform,but the existence of step difference makes the final output voltage ripple.Finally,the hardware circuit design based on DSP platform is given.After the debugging of each module is stabilized,the corresponding experimental platform is built.In the resonant state,the experiment successfully illuminates the 220V/20 W bulb.The feasibility and correctness of the capacitively coupled wireless energy transfer topology in this dissertation are verified,which provides a basis for subsequent research.