A novel noncommunication-based inductive power transfer control technique for battery charging application

In order to realize the precise control of the output voltage and current of the inductive power transfer (IPT) battery charging system, wireless communication-based control are generally employed in a lot of existing works. However, the stability of the IPT converter will be impaired if communication fails. This paper proposes a novel noncommunication-based control strategy with a simple switched controlled capacitor design at the receiver side of the IPT system. A series-inductor-capacitor-capacitor compensation network is selected to verify the proposed control strategy. Without feedback wireless communication, the proposed IPT system can realize reliable constant current and constant voltage output control over full load range at a fixed switching frequency. At the receiver side, switched controlled capacitor is introduced to control reactive current and convey the output-side information to the transmitter side in the form of impedance angle. At the transmitter side, impedance angle is detected in real time, and phase shift control is introduced to regulate the output voltage or current of the system. Detailed analysis, implementation, hardware realization of the proposed noncommunication-based control is presented in this paper. A 250 W experimental prototype is built in the laboratory to verify the proposed control strategy. Constant voltage and constant current for battery charging application are realized through noncommunication-based control. Zero voltage switching over full range of load and minimized reactive current are achieved, which allows high efficiency operation. Compared with existing work in the literature, the proposed noncommunication-based control provides the benefits of reduced hardware cost, higher system reliability and stability.