A Novel Magnetic Coupling Mechanism for Dynamic Wireless Charging System for Electric Vehicles

A novel magnetic coupling mechanism with steady output and low cost is proposed in this paper. It is composed of n-type power supply rail and dual-phase coil receiver. The conventional I-type power supply rail has advantages of narrow width, large lateral tolerance, and low electromagnetic field (EMF) radiation which are suitable for dynamic wireless charging. The double-D coil is used as the receiver which is also seen as a single-phase coil receiver. However, the induced voltage of the receiver has a sinusoidal variation with large fluctuation and has zero point along driving direction. The dual-phase coil receiver is proposed to solve this issue and enhance the output power simultaneously. Compared with the I-type power supply rail, the n-type power supply rail is proposed to improve the utilization of the magnetic core and reduce the construction cost, which is crucial for commercialization of dynamic wireless charging of electric vehicles in the future. The advantages of I-type are also preserved. The enhanced output power of dual-phase coil receiver is verified by circuit analysis. We focus on the influence of the structure size by finite element analysis simulation and the design method of structural parameters is proposed to achieve larger lateral tolerance, greater coupling performance, and lower cost. The structure size is optimized and the analyses are verified by a 10 kW prototype system. The fluctuation of induce voltage has been reduced from 100% to 30%. When the lateral displacement of the receiver is 30 cm at airgap of 20 cm, induced voltage drops by only 30%. The EMF is also measured to ensure safety on the environment.