Design of 3.3 kW wireless battery charger for electric vehicle application considering bifurcation

Bifurcation in a resonant inductive power transfer (RIPT) system causes hard switching of the primary side inverter, decrease in efficiency and loss of control stability. Bifurcation can be avoided by either selecting complicated control strategies or by calculating the parameters of RIPT system in such a way that the system has only one resonant frequency for the entire expected range of load and coupling variations. Many control methods to tackle the bifurcation issue have been covered in the literature. This paper aims at handling the bifurcation by proposing an analytical design procedure. A fabricated system, based on the parameters calculated using presented design steps, avoids the bifurcation phenomenon for the entire coupling and load variations. A 3.3 kW wireless charger setup using series-series compensated RIPT (SS-RIPT) system and 2-phase interleaved boost power factor correction (PFC) as a front end converter has been designed using the proposed method as an example. Simulation results using MATLAB are presented to verify the proposed design methodology.