3.5-kW 94.2% DC-DC Efficiency Capacitive Power Transfer With Zero Reactive Power Circulating

Most existing capacitive power transfer (CPT) circuits are developed from basic series-series CPT compensation, which have a common drawback of unavoidable reactive power circulating from the primary side of the capacitive coupler to its secondary side, causing reactive power loss, weakening power transfer capability, and aggravating electric field emission. To solve these concerns, this letter proposed a parallel-parallel (PP) compensation-based CPT system with double-side series-parallel (SP) inductive power transfer (IPT) links. The PP CPT compensation aims at zero reactive power circulating while the SP IPT links achieve high-power transfer capability. A 2.5-MHz prototype is implemented, and experiments validate the zero reactive power circulating property with 3.55 kW output power at a 94.2% dc-dc efficiency, and the peak efficiency achieves 94.6% at 1.62 kW output power. This letter is accompanied by slides as multimedia material demonstrating the motivations, contributions, and advantages over existing state-of-the-art CPT designs.