Modeling and Suppression Method of the Floating Potential in Inductive Power Transfer Systems for Monorail

In inductive power transfer (IPT) systems, the high-frequency voltage variations in coupling coils can induce an undesired floating potential on ungrounded surfaces, posing a safety risk. Considering the long rail-type coil structure, circuits on transmitting (Tx) and receiving (Rx) sides, an equivalent model of displacement current paths is proposed for predicting the floating potential on sorting transfer vehicles in monorail IPT systems. An expression for floating potential is then derived, revealing that the placement of compensation components for Tx coil is the main factor affecting the floating potential. Based on it, we propose the novel suppression approaches through symmetrical split resonant inductors and strategic repositioning of the Tx coil compensation elements. Experimental validation is conducted using 1-kW power pick-ups with a 3-m-long Tx coil. Experimental and simulation results confirm the validity of the analysis. Adopting the proposed method, remarkable floating potential suppression is achieved from 50.2 V to a near-zero level.