Design of an IPT Battery Charger with Double-sided LCC Compensation

A high-performance IPT charger should provide the battery required constant charging current and constant charging voltage efficiently in the whole charging process. With a wide load range from the battery charging profile, it is hard to realize the first load-independent constant current (CC) and the late load-independent constant voltage (CV) in one converter, whilst the nearly zero reactive power and soft switching of power switches should be realized simultaneously. To solve it, this paper systematically analyzed the characteristics of an double-sided LCC compensated IPT converter and proposed a design method to realize the battery required load-independent CC and CV outputs at two zero-phase angle (ZPA) frequencies. The design combats the constrains of IPT transformer and input voltage, which facilitates to use the simple duty cycle control running at two fixed operating frequencies for both CC and CV. The sensitivities of compensation parameters to input impedance, output current and voltage are also discussed. Finally, an IPT charger prototype will be built to verify the analysis in the final version.