Detection of EVs on IPT highways

Abstract

Electric Vehicles (EVs) are quickly gaining widespread interest as attractive alternatives to conventional petrol driven vehicles. If EVs can derive some or all of their electrical power from renewable sources, then they can significantly help to reduce global dependence on fossil fuels for transportation. Inductive power transfer (IPT) is a method that can transfer power to EVs over an air-gap without physical contact. If IPT systems are incorporated into the highway networks, then EVs can be charged dynamically as they travel. This will dramatically increase the range, convenience and safety of EV charging as well as reduce range anxiety and the required battery bank capacities. However one of the major difficulties involves accurately detecting an EV as it travels along the IPT highway. By detecting the approaching EV, the primary power supply can enable power transfer by energizing the primary IPT coupler buried in the roadway just before the EV is ready to efficiently couple power from the road. A three coil detection system is proposed to allow the primary power supply to detect the approaching secondary IPT coupler mounted on the EV. The proposed detection method is tested on a laboratory scale prototype and can detect EVs approaching at different speeds, ground clearances and horizontal misalignments.