Basic Evaluation of Electrical Characteristics of Ferrite-less and Capacitor-less Coils by Road Embedment Experiment for Dynamic Wireless Power Transfer

The power transmission coils are embedded in the road for Dynamic Wireless Power Transfer (DWPT). However, it has not been discussed conventionally the optimum coil type, material, and construction method embedded in the road. Therefore, in this study, we evaluated the electrical characteristics by embedded seven DWPT coils in the road and compared the coil types, coil case materials, and construction methods. As a result, we clarified the changes in the characteristics of the open-end coils before and after embedment. There are two types of coil, short-end coil (conventional) and open-end coil that does not use resonance capacitors. There are four types of coil case materials: polypropylene (PP), polyethylene (PE), ABS, and extruded polystyrene foam (XPS). There are four types of construction methods: RC mesh G-M, earth-retaining plate, stretch film, and cement grout. Electrical characteristics were evaluated by measurements with an impedance analyzer and power transmission experiments of less than 50 W. As a result of the road embedment experiment, even without ferrite and capacitor, the Q factor was nearly 200, and the power of more than 2 kW was obtained at the 91% transmission efficiency at 600 V equivalent value.