| Abstract |
This article focuses on Inductive Power Transfer to implement dynamic charging for electric vehicles.The system proposed is composed of adjacent 50-cm-side square coils set on the road, with only the coilunder the vehicle activated for power transfer. It relies on a symmetrical circuit coupled to a symmetricalcontrol using ZPA regulation to operate frequency-varying inverters, using soft switching around90 kHz. This system is able to deal with large coupling factor variations (between 0.1 and 0.26, andeven more), which allows to use same-size coils on the ground and on the vehicle, to reduce stray fieldand improve safety. Moreover, the regulation works with no communication between the vehicle and theroad. The idea of short-circuiting a ground coil and its resonant capacitor has been used to determine theposition of the vehicle in order to switch from one activated inverter to the next for dynamic operation.Different scenarios were investigated and experimented regarding the different possible states of groundinductances: on, off or short-circuited with the capacitor. This study leaded to the choice of a scenarioimplemented on a 2.4-kW prototype involving a Renault Twizy as the vehicle carrying the secondaryinductance. The control method employed allows dynamic operation with no additional sensor, resultingin a very good time response of 4 ms, coherent with a motorway application. |
