A Multiple Independent-Load Output Capacitive Power Transfer System With High Coupler Misalignment-Tolerance for Railway Applications

Electronically controlled pneumatic (ECP) system is essential to ensure the railway transportation system's braking safety. Traditionally, the ECP system needs a long cable to supply power for each train body's brake controller. However, a train has many bumps, and the transmission lines and plugs easily fall off simultaneously. It brings severe challenges to the safe and reliable operation of the railway system. This paper proposes a capacitive power transfer (CPT) system to supply power for a long-distance and multiple-load ECP brake system to solve this problem. The proposed system has the following characteristics: 1. It can supply power to multiple loads simultaneously; 2. The variation of load resistance will not affect the other load; 3. The output of each load will not be largely affected by the coupler misalignment. The transmitter of the proposed CPT system adopts CL compensation, while the receivers adopt LCCL topology. The receiver not only receives the electric power for the load but also transfers the power to the next load. A scaled-down experimental prototype with three loads was implemented to verify the proposed theory. The experimental results agree well with the analysis. With a 200 mm misalignment (2/3 length of coupler plates), the output power can reach 83.32 W (150 W rated). The change rate of the output voltage is less than 12% when other receivers are moved out.