AC Processing Controllers for IPT Systems

Inductive Power Transfer (IPT) systems allow electrical energy to be transferred over a relatively large air gap via high frequency magnetic fields. Such systems can be broadly classified based on application, but all such systems have various key components that include; the power electronic transmitter, the receiver electronics, the magnetic coupler and the power flow controller. The purpose of using a power flow controller is to regulate the power delivered to a load using a reference independent of system parameter variations of the IPT system. Some of the common parameters which can cause variations in the power transfer of an IPT system are load resistance and coupling coefficient. Recently, a new type of power controller called an AC processing pickup has been proposed with significant advantages in terms of increasing system efficiency, reducing pickup size and lowering production cost compared to traditional pickups that also produce a controlled AC output using complex AC-DC-AC conversion circuits. This new controller is in two forms but both forms regulate AC power directly and produce a controllable high-frequency AC source over a wide load range suitable for lighting and EV charging applications. This chapter outlines the details and operation of the two different types of AC processing pickups along with analytic analysis. Simplified design examples with practical implementation methods will be presented for systems with variations in load and coupling.