Guo Yanjie

The power loss analysis for resonant wireless power transfer

Efficiency is a very important parameter for kilowatt-level wireless power transfer system (WPT). In order to improve efficiency, we should firstly analyze the power loss in every component of WPT system. Based on the systemic analysis the power loss, we pay more attention on the loss in the coils and car shell caused by eddy-current at high frequency. And some efficient measures have been taken to decrease the loss in the coils and car shell and verify by the Finite Element Analysis (FEA) and experiments.

Effects of temperature on dynamic characteristics of li-ion batteries in electric vehicle applications

Temperature is a key factor that influences the dynamic performance of lithium-ion batteries. The purpose of this study is to investigate the effects of temperature on dynamic characteristics of lithium-ion battery. In this article, the charge and discharge behaviors are studied through battery tests at different temperatures. Based on the tests, the maximum available charge and discharge capacity is analyzed. A model-based subspace identification algorithm is adopted to investigate the quantitative effects of temperature on internal resistance and polarization. Results show that both internal resistance and polarization time increase as the temperature decreases. This explains the reason for difference in dynamic characteristics of lithium-ion battery at different temperatures.

FEM simulation and experiment of a novel shielding structure of wireless power transfer system

The resonant coils are the significant part of the whole wireless power transfer system. The magnetic field leakage will cause the human exposure to time-varying electromagnetic fields problems and low coupling coefficient. In this paper, a 3D model is established to simulate the magnetic field. A new shielded structure is proposed in this paper. A comparasion of the magnetic field between shielded structure and unshielded structure is presented in this paper. An experiment of 8kw and 10kw wireless power transfer system are established in this paper. And as the results of simulation and experiment, the new shielded structure achieve the higher coupling coefficient and suppress the magnetic field leakage.