Wireless power transfer (WPT) of plug-in and battery electric vehicles (PEV�s) rely on loosely coupled transformer operating in magnetic resonance to tune out reactive effects. Depending on the degree of coupling, such systems experience a single peak response that trends to bifurcate as the coefficient of coupling increases. This places additional burden on the WPT grid side power controller to not only manage the power transfer process but to manage the transmit coil to receiver coil reactive power in response to vehicle ground clearance and misalignment tolerance. In addition, the WPT rectified output voltage must dynamically match the vehicle on-board regenerative energy storage system (RESS). This paper examines the essentials of WPT operation and challenges facing the commercialization of wireless charging. Experimental results obtained from the Oak Ridge National Laboratory WPT apparatus are presented as validation of the theory.
PresenterJohn Miller, ORNL