Ricerc@Sapienza

A novel design of active coil shielding is proposed to reduce the magnetic field generated by the currents flowing into the coils of a wireless power transfer (WPT) system for charging the batteries of an electric vehicle (EV). The main idea is to divide the traditional active loop used to shield a source in two separate shielding coils so as not to adversely affect the WPT performance.

The shielding technique by active coils is proposed to mitigate the magnetic field produced by a dynamic wireless power transfer (WPT) system for wireless recharging the batteries of in motion electrical vehicles (EVs). Active planar coils mounted in an electrified road with multiple-pads architecture are proposed. The active coils are adequately powered so that the field in surrounding of the electrified road is compliant with reference levels (RLs) of ICNIRP 2010 guideline. The influence of the active shielding system on the performance of the WPT system is also investigated.

This study deals with the optimization of a shielding structure composed by multiple active coils for mitigating the magnetic field in an automotive wireless power transfer (WPT) system at 85 kHz. Each active coil is independently powered and the most suitable excitation is obtained by an optimization procedure based on the Gradient Descent algorithm. The proposed procedure is described and applied to shield the magnetic field beside an electric vehicle (EV) equipped with SAE standard coils, during wireless charging.

Transmission Line (TL) theory was proposed in the past to model field propagation through conductive shields and it is currently widely used. Recently, this theory has been revisited to investigate the shielding of near-field sources by analytical and numerical techniques. The recently developed methods are here applied to analyze simple configurations of near field shielding.

This paper deals with the application of the recently developed artificial material single layer method to efficiently model a thin conductive anisotropic material using commercial software tools based on the finite element method. In the present work the method is applied to the prediction of the magnetic field in an electric vehicle made with metal or carbon fiber reinforced polymer (CFRP) bodyshell and equipped with a stationary wireless power transfer system. Simple tests are presented to show the performance of the method.

An improved second order artificial material single layer (AMSL) method is proposed to predict the electromagnetic field in presence of conductive thin layers by the finite element method (FEM). The AMSL method is based on the replacement of the material physical constants of a conductive shield region with those of an artificial material. The new AMSL physical constants are analytically extracted by equating the equivalent transmission line (TL) equations governing the field propagation inside the shield with the FEM solution.

This paper deals with the extension of the artificial material single-layer (AMSL) method, recently developed to model electromagnetically a thin conductive material using the finite-element method (FEM), to the more general case of transversally anisotropic shields. The analogy between the field equations and the multiconductor transmission line (MTL) equations is here used to calculate the admittance matrix of a thin anisotropic material. This admittance matrix is then imposed to be that of an equivalent circuit with lumped parameters.

An innovative shielding configuration of active coils is proposed to mitigate the magnetic field around an electric vehicle (EV) with a wireless power transfer (WPT) system during battery charging. The active coil is designed to reduce the risk for patients with pacemakers or similar devices produced by the time varying magnetic field generated by the 85 kHz WPT coil currents. A numerical analysis of the magnetic field levels is carried out solving the magneto-quasi-static (MQS) equations by a FEM-based commercial tool.

A novel design of active coils is proposed to reduce the magnetic field generated by the currents flowing into the coils of a wireless power transfer (WPT) system for recharging the batteries of an electric vehicle (EV). The main idea is to split the traditional active loop, in two separate shielding coils. They have semi-annular shape and are placed on the ground pad around the WPT primary coil. The geometry and excitation of the active coils are varied to minimize the magnetic field beside the active coils without degrading the WPT electrical performance.

The shielding technique by active coils is proposed to mitigate the magnetic field produced by a wireless power transfer (WPT) system based on near field coupling. General guidelines are provided for the active shielding design to shield the source for emission reduction or to shield the victim for immunity enhancement. Then, a method is proposed to identify the suitable excitation of the active coils. The proposed method permits the mitigation of the magnetic field in a specific point or of the induced effects in a loop area.