Study On Power Stability Of Dynamic Wireless Power Transfer System

Wireless Power Transfer(WPT)technology has some advanced properties such as good insulation,high safety,high environmental adaptive,etc.It has been extensively studied in electric vehicles,electronic devices,automatic guided vehicles,.implantable medical devices,and so on.Dynamic Wireless Power Transfer(DWPT)approach utilizes a non-contact method to transfer electrical energy from the transmitter coils laid under the ground to the receiver coils,which can reduce battery capacity,reduce parking and charging time,even achieve battery-free,and improve production efficiency.In the DWPT system,the coupling coefficient and load are frequently changing because of the relative movement of the transmitter and receiver coils,the non-unique loads,and the increase in the internal resistance of the load during the charging process.Which is not conducive to the stability of power transmission between the primary and secondary coils.Reducing the fluctuation of transmitted power when the parameters change has a positive effect on the lifespan and reliability of the system.Therefore,it is of great significance to improve the stability of power transmission in a DWPT system.In this paper,the power stability of DWPT system is studied through compensating network design.Firstly,two low-order S-S compensation networks,the resonant compensation network and the primary-side detuned compensation network,are taken as an example to compare and analyze the output power when the coupling coefficient and load are varying.The primary-side detuned compensation network was proved to be higher power stable to the variation of parameters.It is also founded that the LCC-S detuned network has higher design freedom compared with the S-S detuned network.Then,the LCC-S primary-side detuned compensation network is fully designed:analyze the output power characteristics under the dual parameters of coupling coefficient and load as well as the soft-switching characteristics of the system.By defining the detuned factor,the value of the detuned factor is fully studied.The influence of output characteristics and soft-switching characteristics are analyzed,and the influence of high-order harmonics on the system input current is researched.The efficiency and system power factor are studied,and a multi-parameter design method is proposed.Finally,the feasibility and correctness of the scheme are verified through PSIM/MATLAB simulations and a low-power experimental platform.