An Optimized Track Length in Roadway Inductive Power Transfer Systems

Application of inductive power transfer (IPT) to electric vehicles moving along the road can provide more charging flexibility with the reduction of weight and size of charge-storage batteries required in the vehicles. Existing research focuses on the efficiency improvement and alignment tolerance of the IPT transformer. Consideration of the transformer track length and the vehicle speed is rarely discussed. In this paper, an IPT vehicle charging system using a series of sectional tracks is studied. The relationship among various key parameters, such as vehicle speed, system efficiency, and power utilization of the IPT system, is studied in detail. Specifically, the impact on efficiency due to variation of track length and edge correction is reported. The extension of the system from a single pickup to multiple pickups is discussed. The results are verified with finite-element-analysis simulation and a scale-down experimental prototype.