A Low-Power Capacitive Wireless Power Transfer System With Autonomous Misalignment Correction Using Array Electrodes

초록

Capacitive wireless power transfer (CPT) systems are highly sensitive to coupling misalignment because variations in electrode alignment directly change the coupling capacitance and disturb the resonant condition, resulting in a degraded output power and efficiency. This paper proposes a low-power CPT system with autonomous misalignment correction using an array-electrode capacitive coupler and a hierarchical control strategy. The proposed system maintained a viable coupling state under lateral and rotational misalignment by sequentially reconfiguring the transmitting electrode pair, searching for the resonant operating frequency, and adjusting the inverter DC input voltage based on the received output condition. In addition, amplitude-shift-keying-based feedback was used to indicate whether the output voltage was sufficient for normal operation. The array electrode structure is designed to preserve an approximately constant effective coupling region over different receiver positions, thereby reducing the sensitivity of the system to positional variation. The proposed concept was verified through simulations and hardware experiments. An implemented system operating at 826 kHz with a transfer distance of 0.5 mm demonstrated autonomous correction under various misalignment conditions while delivering up to 151.32 mW with a peak power transfer efficiency of 78.21%. The results confirmed the feasibility of the proposed approach as a low-power free-positioning CPT platform for applications requiring robust operation under receiver position variation.

키워드