Efficiency Improvement Under Coupler Misalignment for Dual-Transmitter and Single-Receiver Capacitive Power Transfer System

This article proposes an efficiency improvement method for the dual-transmitter (Tx) and single-receiver capacitive power transfer (CPT) system under misaligned conditions. A ten-plate-based dual-Tx capacitive coupler, including transmitting, receiving, and shielding plates, is established and modeled. The equivalent circuit of the dual-Tx CPT system is built and analyzed. The relationship between the maximum efficiency point (MEP) and input impedances of two Txs is derived theoretically. The MEP can be achieved by regulating the input voltages of two Txs when the input impedances of the two Txs are the same under misaligned conditions. To validate the feasibility of the proposed efficiency improvement method, a 1.6-kW prototype is constructed. To ensure the fairness, all efficiency comparisons are based on the premise that the output power is equal. The experimental results show that the system efficiency is highest when the dual-Tx CPT system's input resistance is equal under any misaligned conditions. Even when the misalignment distance is more than 15 mm and the total air gap of two Txs is 60 mm, the optimal efficiency remains stable.