Double-coupled systems for roadway IPT systems

Dynamic powering of in-motion Electric Vehicles (EV) using Inductive Power Transfer (IPT) can potentially solve many of the problems currently faced by EVs: in particular range, cost and charging rate. However there is currently limited research focused on suitable IPT primary supply-side infrastructure for such roadway IPT systems, and most proposed systems so far have limitations which affect their usefulness and/or suitability. This paper presents a new roadway IPT system called the “double-coupled system” (DCS) which can resolve these limitations. The proposed system introduces an “intermediary coupler” (IC) circuit between the power supply primary track and each ground transmitter pad/coil arrangement. Individual power sections on the roadway can be controlled independently using the intermediary couplers and only turned on when required, and as such minimize unwanted magnetic leakage fields. The proposed system is highly reliable and fault tolerant, allows high power transfer at high frequency, and is also efficient and cost effective. It can also reduce the impact of dynamic EV charging on the electrical grid at the times of traffic congestion. A laboratory scale prototype system has been constructed and tested. The intermediary coupler achieved an efficiency of 85% at an output power of 5kW with full system operability.