A Study on the circuit configuration with capacitors to compensate the power factor for high-power contactless power transformer

The contactless power transfer systems have recently attracted much attention as it is possible to supply electrical energy to vehicles without cables. We have studied high-power contactless power transfer systems in the hundreds of kilowatts power range for the purpose of applying it into the railway vehicles. In this system, resonant capacitors are used to compensate the input power factor. Problems in high-power contactless power transfer systems using resonance capacitors arise from the maximum voltage and current limit of the capacitors owing to high reactive power. Thus it is important to select a topology whose reactive power is lower. In this paper, the Series-Parallel (SP) topology and the Series-Series (SS) topology are discussed for high-power contactless power transfer systems. The contactless power transfer coils for supplying 300kW are designed for both topologies by means of electromagnetic analysis and it is clarified that the reactive power of the primary side in the SP topology is lower than that in the SS topology. In addition, the result that the coils in the SP topology are lighter than that in the SS topology is presented.