A multi-loads capacitive power transfer system for railway intelligent monitoring systems based on single relay plate

This paper proposes a multi-loads capacitive power transfer (CPT) system based on a single relay plate for railway monitoring systems. The proposed system can supply power wirelessly to the monitoring system on the trackside and train carriages simultaneously to eliminate traditional power cables connection and prevent frequent battery replacement. Unlike the traditional multiple loads CPT systems, the proposed system uses only one relay plate, which is more stable and uncomplicated considering the coupler installation space and moving dynamically in the railway system. The proposed system adopts a CL-LCLC-CL compensation network to achieve a load-independent output. The limitation of the charging load quantity is given in detail considering the coupler voltage stress distribution. An experimental prototype with three loads is also built to verify the effectiveness of the proposed system. Experimental results show that the proposed system achieves wireless power transfer to multiple loads simultaneously with two loads on the receiver and one on the repeater side. The load-independent property is also achieved when two loads are removed. The maximum experimental efficiency is about 87.13%.