Analysis of Capacitive Wireless Power Transfer

Abstract

The analysis of capacitive wireless power transfer was conducted in a general manner. The circuit model of a capacitive wireless power transfer chain was presented. The derivation of the power transfer efficiency through the chain in question as well as the active power delivered to the appliance terminating this chain was shown. Both the case of the maximal efficiency and the one of the maximal appliance power were treated and conditions for these optima were found in both cases. The appliance power corresponding to the maximal efficiency and the efficiency corresponding to the maximal appliance power were also expressed. The total admittance of the capacitive wireless power transfer chain was calculated. For both optimal conditions, the appliance power and total admittance were written in the normalized form, which enabled to express them as functions of single variable in the same way as the efficiency.

Capacitive Wireless Power Transfer with Multiple Transmitters: Efficiency Optimization

“…The optimal terminating load admittance corresponds to the value found in scientific literature for a CPT system with a single transmitter (N = 1) coupled to a single receiver [30][31][32].…”

“…The higher the system kQ-product α N , the higher the efficiency of the system, as can be seen by Equations (27), (28), and (31). The maximum efficiency η max of the CPT system can thus be increased by adding more transmitters to the system, even if the transmitters themselves are coupled.…”

“…Equation 32is physically not possible since 0 ≤ η max ≤ 1. The maximum attainable power-transfer efficiency η max is therefore expressed by Equation (31).…”

“…By using the values reported in Equation (59), the extended kQ-product α n , the system kQ-product α N , and the inductors L j , can be calculated from Equations (28), (27), and (58), respectively, and are listed in Table 3. As per the maximum efficiency, a value of 84.9% is attainable, according to Equation (31). The parameters at which the maximum efficiency configuration is reached are listed in Table 4.…”

PCB Layout Optimization of High-Frequency Inverter for Magnetic Coupled Resonance Wireless Power Transfer System

“…the transfer frequency is generally several tens of kHz to tens of MHz. Within limits, increasing the frequency of the MCR-WPT system can effectively increase the transfer distance of the system, and decrease the size of the coupling coil, and improve the portability and practicability of the system [5]. This provides a good performance for low-power applications such as home appliances, material handling, and forklift charging, etc.…”