Optimal operation point tracking control for inductive power transfer system

Inductive power transfer (IPT) is emerging as a solution to achieve power transfer without physical contacts for a wide range of applications, such as electric vehicle charging. Improving the efficiency of the IPT systems through power electronics and control has become a focus to make IPT competitive to the existing contact power transfer solutions. This paper reviews and evaluates the state-of-the-art IPT control methods and proposes an optimal operation point tracking control for the IPT system. The proposed method controls the switching frequency, transmitter and receiver PWM duty-cycles to compensate for changes in gap distance, coil misalignment, temperature and component parameter tolerance. The optimal operation points are tracked to improve the overall system efficiency. The proposed method is analyzed by comparing the different operating points at power and efficiency curves of the IPT system. Furthermore, a 4.5 kW IPT prototype is designed and three control strategies are implemented and tested in the IPT prototype. The experimental results verified that the proposed optimal operating point method effectively improves the system efficiency and tolerance to environment variables.