Circuit modeling and efficiency analysis for wireless power transfer system with shielding.

Summary: It is an effective way to use magnetic shielding scheme in magnetic coupled wireless power transfer (WPT) system to reduce magnetic flux leakage. However, the additional shielding material would affect the equivalent circuit model and the power transmission efficiency of WPT system. Although the impact of some common shielding materials on the transmission efficiency has been studied using finite element simulation, there is still a lack of understanding about the impact to the equivalent model in theory. In this paper, the equivalent circuit and transmission efficiency of WPT system are analyzed theoretically under the influence of different shielding materials, and the relationship between material electrical characteristics and transmission efficiency is presented. In our WPT prototype with two 166‐mm diameter coils under ferrite shielding and aluminum shielding, the achieved maximum transmission efficiencies are 95.7% for 100‐kHz resonant frequency and 97.9% for 1‐MHz resonant frequency under the ferrite shielding, and the efficiency errors between the analytical and experimental results are less than 5% for 100‐kHz resonant frequency and 10% for 1‐MHz resonant frequency. The equivalent circuit and transmission efficiency of wireless power transfer system are analyzed theoretically under the influence of different shields, and the relationship between material electrical characteristics and transmission efficiency is presented. The analyzing and experimental results show that shields with high permeability and low electrical conductivity are beneficial for enhancing the transmission efficiency of WPT system. [ABSTRACT FROM AUTHOR]