A New Analytical Formula for Coupling Capacitance of Unipolar Capacitive Coupler in Wireless Power Transfer System

In this research, using response surface methodology (RSM), an analytical formula as functional dependencies on the six specified geometrical parameters is developed for coupling capacitance (Cm) of a capacitive power transfer (CPT) device. The geometrical parameters include the physical and misalignment parameters of the plates. Using the variance analysis, the sensitivity of the Cm value to variations in the geometric parameters of the CPT device was investigated. The established analytical formula allows for easy calculation of the Cm value specific to the CPT devices for their different geometric parameters, including for different misalignments. It is also particularly useful in optimal design of the CPT devices. However, it was found that the misalignment parameters have a negligible effect on the Cm. On the other hand, the physical parameters have an effect of 46%, 38%, and 16% for the transmitter plate area, receiver plate area, and air-gap between them, respectively.