A New Type of IPT System with Large Lateral Tolerance and its Circuit Analysis

A new kind of inductive power transfer (IPT) structure for electric vehicles (EV) appears recently. The new structure can greatly increase the air gap and lateral tolerance. Those merits are described and analyzed in this paper. It can be seen from analysis that a longer, wider magnetic core and wider coil width increase the coupling coefficient. A new circuit structure composed of LCL compensation and the buck circuit is also described in this paper. Current in the primary side of the circuit will vary with load demand. This way, higher efficiency can be achieved when power transferred is small. A 2kW prototype IPT system is built based on these techniques. When the air gap and lateral tolerance reaches 38cm and 40cm separately, the efficiency is acceptable.