A General Voltage Optimization Method for Different Capacitive-Power-Transfer Coupler Pairs

Due to the small dielectric constant in air, the corresponding small coupled capacitances make a capacitive power transfer (CPT) system usually suffer high voltage stresses not only on the face-to-face coupler pairs but also on the lateral and crossing coupler pairs, thus increasing the risks of air breakdown and electric field (E-field) radiation. To solve it, this brief proposes a general method to optimize the aforementioned voltage stresses on the different coupler pairs simultaneously via a voltage vector triangle model. The detailed design principles involving the key parameters of compensation network are also given for four basic compensations. Besides of voltage optimization of coupler pairs, a CPT system is usually required to provide the load-independent constant current (CC) or constant voltage (CV) output under a specified power level. Therefore, the high-order compensation networks are used and analyzed to increase the design freedom of the basic four compensations and achieve controllable CC/CV output, while the voltage characteristics on the coupler pairs still remain. Finally, a 1 MHz LC-LCLC compensated CPT prototype is demonstrated and implemented with load-independent CV output, input zero-phase angle (ZPA), and voltage simultaneous optimization on all coupler pairs.