Exploration of a new load detect method for wireless power transfer system—third harmonic analysis

Abstract

Wireless power transfer (WPT) is an emerging energy transmission method that can transmit energy omnidirectionally or directionally. WPT systems mainly use electromagnetic fields and operate through two main technologies: inductive coupling and resonant inductive coupling, and are widely used in various applications ranging from small electronic devices to electric vehicle charging. The development of efficient and safe WPT technology has the potential to revolutionize the industry by providing a more convenient, flexible and safer way to transmit energy. At present, directional power transmission has become a hot topic of research due to its high efficiency. To achieve directional energy transmission, it becomes crucial to accurately detect the energy demand of the load and its relative position. In this paper, a load detection method based on third harmonic analysis is designed. By analyzing the third harmonic of the primary voltage and current, the load resistance and position information can be accurately obtained. A two-dimensional WPT system is established in ANSYS, and the inductance values of different positions of the receiving coil are obtained by simulation. In addition, a simulation model is constructed in MATLAB to verify the feasibility of the third harmonic analysis method. The experimental results show that in most cases, it is feasible to use third harmonic analysis for load detection of WPT system, and the results have high accuracy.