Frequency Optimization Control And Band Division Of Two Coils Series Series Magnetically Coupled Resonant Wireless Power Transmission System

Magnetically Coupled Resonant Wireless Power Transmission(MCR-WPT)has advantages of large transmission power,moderate distance,and high transmission efficiency,etc.For a prospecting future in the application areas of transportation,power systems,biomedicine and underwater working,MCR-WPT attracts the attention from the researchers in various countries.The operating frequency of the MCR-WPT system,as the core parameter of system optimization control and operation,has always been the research focus of this technology.With the development of MCR-WPT technology,more and more wireless power supply equipments will be put into application.The MCR-WPT system is facing problems such as frequency optimization control and working frequency band selection after transmission distance.In response to these problems,this paper takes the two-coil series-series(SS)MCR-WPT system as the research object,and conducts research on the frequency optimization control strategy and the system frequency band sequence division after the system transmission distance changes.The main contents of this paper are as follows:(1)The electromagnetic theory is utilized to calculate and analyze the spatial electromagnetic distribution characteristics of the two-coil MCR-WPT system,and then the system coil parameter self-inductance and mutual inductance calculation formulas are proposed.For the operating state of MCR-WPT system,the circuit model theory and coupled mode theory are used to model and analyze the two-coil SS-type MCR-WPT system to obtain the relationship between the system transmission efficiency,power and resonance frequency,mutual inductance.(2)Combined with the analysis results of the circuit model theory of the two coil SS MCR-WPT system,it establishes the target optimization model of the maximum transmission efficiency of the system and the particle swarm optimization(PSO)algorithm is employed to compute the resonant frequency related with the system’s maximum transmitting efficiency at different transmission distances.Thus,the MCR-WPT system frequency controlling strategy based on the PSO algorithm comes out.Finally,it simulates the MCR-WPT system based on the PSO algorithm frequency controlling strategy with PSIM software and MATLAB software.The simulation analysis of the running state of the MCR-WPT system prove the effectiveness and correctness of the control strategy.(3)According to the operating state of the MCR-WPT system based on PSO algorithm frequency controlling strategy,the distance principle for dividing the resonance frequency range of the MCR-WPT system is proposed,and the resonance frequency sequence based on the distance principle is obtained,so that different transmission distance ranges correspond to different resonance frequency sequences;also considering the MCR-WPT operational indicators such as system operation economy etc,the principle of improved geometric mean value is proposed and the division result is revised,thus,the revised resonant frequency sequence recommended value is obtained.Besides,in order to enhance the adaptability of the MCR-WPT system to load changes,a method for determining the working frequency band based on the load characteristics is proposed,and the resonance frequency point is extended to the working frequency band;then,the resonance frequency sequence and the working frequency band are combined to realize the frequency band division of MCR-WPT system based on two coils SS.Finally,an experimental platform is built to verify the feasibility and rationality of the frequency band division result.