Yang Qingxin

Characteristics of 3D magnetic field of magnetic coupling resonant wireless power transmission system

Purpose The purpose of the paper is to analyze the impact of coupling on the distribution of the magnetic field and study the characteristics of the magnetic flux density in the transmission process of the magnetic coupling resonant wireless power transmission (MCR-WPT) system, which provides guidance on the design of the WPT system. Design/methodology/approach In this study, a finite element simulation analysis was conducted and a three-dimensional (3D) electromagnetic field measurement platform was used. Findings It is shown that the distribution of the magnetic field, as well as the position of maximum magnetic flux density, will change when the coils are coupled. The simulation results of the magnetic field distribution, as well as the transmission performance, are different from those in practice. It cannot describe the actual performance of WPT system. Originality/value A 3D electromagnetic field measurement system and the host computer software are designed to help optimize the simulation and carry out more accurate and efficient research. The 3D electromagnetic field measurement system can be used to study the distribution of the spatial electromagnetic field, influencing factor, exposure and interoperability between different coils.

Numerical estimation and optimization of vibration noise due to magnetostriction and magnetic forces for laminated core structure

We proposed a new approach for estimating the vibration and noise caused by magnetoelectric effect and magnetic force via finite element analysis. With this method, the relationship between inputting magnetic field and outputting vibration level of laminated core structure in power transformer could be obtained. The essential reason of vibration is analyzed and a kind of nanocrystalline soft magnetic composite material (NSMC) with high permeability is applied to fill the air gaps between the sheets. It is intended to verify the correctness of this method, that a 3D magneto-mechanical strong coupling model containing anisotropic silicon steel sheets was built and solved. From the experimental results, the deformation and noise level with NSMC are significantly better than that with the traditional epoxy damping material based on Epstein Frame.

A novel two-port network model for RCPT system

Purpose – The purpose of the paper is to show that how a contactless power transmission system via electromagnetic (EM) resonantly coupling power transmission (RCPT) technology may be analyzed in-depth by using a detailed T-type two-port network model with leakage inductance variable. Design/methodology/approach – Through the introduction of coupling coefficient and quality factor, the influence of different physical parameters on the system performance is taken into consideration and validated by power transmission experiment. Findings – It is shown that system performance is mainly subject to coupling coefficient and quality factor from the two-port network model in this paper. Moreover, there are three working status of dynamic transmission, which are over coupling, critical coupling and under coupling. Originality/value – Two-port network model applied to practical RCPT system design considering impedance loss on resonators, etc.

Numerical analysis on electromagnetic characteristics of laminated core joints of power transformer

In this paper, a new practical three-dimensional model for laminated core joint is proposed considering its anisotropy characteristic. It can be easily solved by Finite Element Method(FEM) in which an efficient sparse matrix handling method is employed. Flux density distribution of different styles of core joints is shown. It provides a high efficiency and accurate method for study electromagnetic characteristics of laminated core joints.