Capacitive Power Transfer System with Double T-type Resonant Network for Mobile Devices Charging/Supply

In some applications with a wireless power transfer of mobile devices, the pick-up of a wireless power supply often needs to be moved in and moved out. This process will cause a sudden change to the system structure, the power electronic device of a capacitive power system (CPT) would be damaged due to high transient voltages or currents, and the standby power of the system will be very high after the pick-up is removed. This paper has proposed a CPT system with a double T-type resonant network to addressed the problems. The steady-state models of the system under no pick-up and normal conditions are established. The relationships between the resonant network parameters are fully analyzed, and a systematic circuit parameter design method is provided. The proposed CPT topology and parameter design method have been verified by the simulation and experimental results. The system not only achieved self-protected under severe load change, but also could automatically enter standby mode after the pick-up is moved out. Besides, the system without additional detection and control circuitry restores to deliver the required power when the pick-up is moved in.