Analysis, Optimization, and Demonstration of a Vehicular Detection System Intended for Dynamic Wireless Charging Applications

Abstract

To overcome the range limitation associated with electric vehicles (EVs), the emerging technology of dynamic wireless power transfer (DWPT) can be employed. Electrified road infrastructure and wirelessly charged vehicle constitute a complex dynamic system whose successful operation requires coordination between the two subsystems and a certain level of knowledge regarding the EV position and speed on the road. A comprehensive vehicular detection system (DWPT-VDS) operating on magnetic principle and intended for DWPT applications is proposed in this paper. The following functionalities are integrated into the DWPT-VDS: a vehicle detection mechanism, the measurement of the vehicle lateral misalignment, vehicle speed measurement, driver information system (DIS), as well as the wireless communication between a roadside power controller and the DIS. When integrated with a DWPT charging system, the DWPT-VDS allows some critical functions, such as correction of the lateral position of the vehicle by the driver, an extended range of full-power reception for a misaligned vehicle, as well as the smooth transition between adjacent pads. This paper presents a comprehensive study of different coil structures and algorithms for speed and misalignment estimation in a DWPT-VDS, along with their comparison. The objective is to maximize the misalignment detection range for a given size of test coils and provide a robust solution for vehicles with different ground clearances. A three-coil system for vehicle misalignment and speed detection is selected as part of a proof-of-concept design. Part of the system is embedded in the road, and the rest is mounted on a wirelessly charged electric bus. The implemented system has been successfully tested in an outdoor environment. A DIS visualizing speed and misalignment information is also developed and tested to help the driver align the vehicle with the road-embedded primary pads.