Wheel Hub Active Power Collection Unit for Dynamic Conductive Road Charging

Traveling hundreds of miles with an electric vehicle (EV) requires a large battery combined with available static fast chargers along the route. Dynamic conductive road charging is seen as an alternative as it allows EVs with smaller battery sizes to travel over longer distances and eliminates intermittent stops for charging. To transfer power during driving, power tracks must be aligned along the road and built either above, beside, or on the road. Therefore, the available EVs’ power collection units (PCUs) are either mounted on the vehicle’s roof or attached to the chassis. For mainstream applications, changing the design of the roof structure and chassis of future EVs would involve enormous development costs. This article presents an alternative for dynamic conductive road charging where the PCU is embedded in the wheel of an EV. Positioning the PCU in the wheel does not require any substantial change to the integrity of the car, and the PCU can easily be removed or added, similar to changing tires. A stationary-hub wheel is used, which offsets the wheel drive motor to an eccentric position, resulting in a static hub that accommodates the PCU. This article describes the design of the PCU and shows simulation results to support the design. An experimental platform was built to validate the concept. The design of the proposed PCU was based on an EV traveling at a high speed (200 km/h) on a motorway.

I. Introduction

The electrification of transportation is one of the most important global revolutions of the modern era. Today, road transport is the source of 22.3% of global greenhouse gas (GHG) emissions [1]. Battery-operated electric vehicles (EVs) powered by renewable energy sources are seen as the main driving force of this revolution. Typically, static chargers are used to charge EVs. Two main static charging concepts are available: conductive charging and inductive charging. Conductive charging requires a cable that connects grid power with the EV, whereas inductive charging is entirely wireless, transferring power via an electromagnetic field generated by a coil embedded in the road and picked up by a coil attached to the underside of the EV’s chassis [2].