Comparative evaluation of control methods for Inductive Power Transfer

Inductive Power Transfer (IPT) has recently been proposed for application with Electric or Hybrid Electric Vehicles (EV/HEV), where a highly efficient system operation is demanded for the high-power transfer. Due to the high requirements on the regulation of the output power and the output voltage, and due to the large variations of the magnetic coupling, the control of these systems is a challenging task. In this paper, the frequency characteristics of a series-parallel compensated IPT system are discussed. Different control methods found in the literature are analyzed and a comparative evaluation of the current and voltage stress in the transmission coils, the resonant capacitors, and the semiconductors in the primary-side inverter is presented. It is shown that the dual control method offers a number of advantages in the controllability and potentially lower losses compared to the frequency control which is commonly used.