A Novel Compensation Circuit for Capacitive Power Transfer System to Realize Desired Constant Current and Constant Voltage Output

Capacitive power transfer (CPT) technique possesses the advantages of safety, isolation, low cost, and insensitivity to conductive barriers. To charge lithium-ion batteries, CPT should possess the output profile consisting of first constant current (CC) output and later constant voltage (CV) output. To fulfill the output profile, many power switches or compensation components are added in the CPT circuit, which is not expected due to the bulky size and additional losses. To reduce the redundancy of the CPT system, an L-x-PS CPT circuit with only five compensation components is proposed in this paper. After a systematic analysis and a parameter design procedure, the proposed CPT circuit can realize input ZPA at both CC and CV modes. In addition, the output current at CC mode and the output voltage at CV mode are all adjustable based on the charging demands of different loads. Finally, simulations are done to prove the analysis in this paper. Compared to previous research, the CPT circuit proposed in this paper can not only achieve the charging demands of lithium-ion batteries, but also reduce the redundancy of the whole system.