Analysis of Inductive Power Transfer according to Resistance loads and air gaps at 50 kHz Frequency

Abstract

-Contactless systems use electromagnetic fields to transport power from railway substation to the traction system. The proto type of inductive power transfer (IPS) system has been developed in order to use train power feeding. It is based on a contactless transformer with a fixed coreless primary and different secondary core like E shape and U shape. The primary coil is supply with 50 kHz current which produces a magnetic flux in the secondary core. Further this flux induces a current in the secondary coil. This paper presents results of experiment for developed inductive power transfer system experiments. The IPS has a large air gap, so it is required a high magnetization current and compensate the leakage flux of primary and secondary coil. The proto type IPS has an air gap with range 1 to 5 mm and core material is ferrite with maximum power of 5 kW. The power supply to IPS is designed by constant current control inverter with compensation capacitance. We measure inductance of IPS and coupling coefficient in order to calculate the compensation parameter according to variable air gap. The analysis of output for the proto type IPS is performed regarding different loads.

Review and research progress of wireless power transfer for railway transportation

“…In order to solve this problem, a shielding coil (Fig. ) using a closed‐loop planar resonant reactive shield was proposed . It was found that the proposed coil structure could reduce the leakage magnetic field up to 83% and improve transmission efficiency to over 91%.…”