Research On Wireless Power Transfer System With Constant Eigen Frequency Control

In recent years,wireless power transfer technology has been widely studied worldwide.Meanwhile,the products of wireless power transfer have been continuously popularized.This technology has been widely applied in medicine,domesticity and industry.Wireless power transfer based on parity time symmetry is a new way of wireless power Transmission.It applies the theory of parity time symmetry in quantum mechanics to wireless power transfer system.Compared to magnetic coupling resonance wireless power transfer,this system overcomes the phenomenon of power bifurcation and keeps the transmission efficiency and transmission power stable within the designed distance.However,it still has many disadvantages,such as low transmission power,frequency variation and the inherent resonance frequency of transmitting circuit and receiving circuit must be equal.Therefore,a wireless power transfer system based on constant Eigen frequency control is proposed in this paper.It not only has the advantages of constant frequency,unequal inherent resonance frequency of transmitting circuit and receiving circuit,but also can keep the constant output power and efficiency of the system.The following studies have been carried out in this paper:1.The status of modeling,efficiency optimization and control methods of magnetic coupling resonance wireless power transfer system is systematically discussed.The inevitability of the development of magnetic coupling resonance to parity time symmetry wireless power transfer is analyzed.The advantages and disadvantages of wireless power transfer system based on parity time symmetry are expounded,and the main ideas and significance of this paper are put forward.2.According to the coupling model of SS-type wireless power transfer system,the relationship between transmission efficiency,transmission power and Eigen frequency are analyzed.The relationship between Eigen frequency and frequency bifurcation is expounded.The reason why the wireless power transfer system based on parity time symmetry overcomes power splitting is explained.It is shown that wireless power transfer based on parity time symmetry is a special case of SS-type wireless power transfer.The limitations of wireless power transfer based on parity time symmetry are analyzed,which lays a theoretical foundation for the analysis of wireless power transfer system based on constant Eigen frequency control.3.The realization conditions of wireless power transfer system based on constant Eigen frequency control are deduced.The expressions of transmission efficiency and transmission power are analyzed under the condition of constant Eigen frequency.The variation range of resonant capacitance on both sides of transmitter and receiver is studied.The role of saturated negative resistance is expounded.Several realization forms of saturated negative resistance are summarized.The control strategy of constant Eigen frequency is proposed.4.The simulation platform and experimental platform of wireless power transfer system based on constant Eigen frequency control are established.The design methods of high frequency AC power supply,adjustable capacitor and transmission coil are analyzed.The system under different output voltage is simulated and experimented respectively.The simulation results,experimental results and theoretical analysis are consistent,which verify the correctness and feasibility of the wireless power transfer system with constant Eigen frequency control proposed in this paper.