The Research Of Wireless Power Transfer System Based On Coupled Magnetic Resonance

Compared with the traditional power transmission mode, the wireless power transmission has the advantages such as saving resource, safety, and convenient, so the wireless power supply is a hot issue in the current research. As the best prospect of wireless power transmission mode, Magnetic coupling resonance WPT uses loosely coupling system between the two coils.So it has the advantages of high efficiency, long distance transmission and high security.Thus many researchers has being attracted to involved in this technology, which has very high research value and huge space for development.In this paper, based on magnetic coupling resonant WPT technology and combining the theory of coupled modes and the circuit theory,building the overall structure and equivalent circuit of the system.Through the analysis and deduction of the system, the characteristics of energy transfer and the inherent law of the system are summarized.Through the analysis of factors of system frequency, coil resistance and coupling coefficient of the impact on system performance, The corresponding parameter values of the system performance are summarized, and the effective methods of improving the output power and transmission efficiency are summarized: 1.Optimize coil parameters the coil parameters; 2.Using frequency tracking, which makes the system frequency match with the load impedance.In this paper, a magnetically coupled resonant WPT system with Buck circuit is designed, which can improve the adaptability of the system to the load. The system consists of three parts, including high frequency inverter, rectifier voltage regulator and Buck circuit., giving a detailed introduction of the asymmetrical half bridge inverter circuit, rectifier filter circuit and Buck circuit design,and the feasibility of the circuit design is verified by simulating. The simulation circuit of the system is built, according to the simulation circuit, the inverter output waveform, the voltage waveform and energy transfer waveform of the load are tested. According to the simulation results, the parameters of the system are optimized, finally, the wireless transmission of electric energy and the function of reducing voltage are realized. The output result is close to the theoretical analysis, which proves the rationality of the system design.