Maximum Available Power of Undersea Capacitive Coupling in a Wireless Power Transfer System

Abstract

This paper studies the maximum available power of a dissipative capacitive power transfer (CPT) system submerged in seawater. The CPT system's maximum power capability is driven using the network theory, precisely the conjugate-image approach. The equations of the maximum available load power and the system's corresponding efficiency are expressed as a function of the capacitive coupling parameters. The experimental results demonstrate that the maximum available power and the corresponding efficiency decreases by a maximum of 10%, which occurs at 1.4 MHz, when the plates' separation distance change from 100 mm to 300 mm. Besides, the system has higher power transfer capability and higher efficiency at a low-frequency range than a high one. The maximum available load power decreases by about 22.5% when increasing the frequency from 300 kHz to 1.4 MHz. Thus, the CPT system can provide a good solution to charge electric ships and underwater vehicles over a wide separation distance and low-frequency range.

Optimal Solutions for Underwater Capacitive Power Transfer

“…It extends the analysis proposed in [14] to include three possible solutions, namely, the one that maximizes the efficiency, the one that maximizes the transferred power, and the one that realizes power matching.…”

“…As proposed in [14], the reciprocal two-port network representation provides a general formulation for the CPT scheme. In this representation, the capacitive couplers are a black box from which only the voltages (u 1 , u 2 ) and the currents (i 1 , i 2 ) can be measured.…”

“…In addition, defining the following two parameters for the convenience of mathematical symbols in [14]:…”

“…It also addresses the IPT's interaction problem with nearby metals and results in avoiding the eddy current losses and fire hazard potential. Consequently, it has been proposed for on-road electric vehicles [5][6][7], underwater vehicles [8][9][10][11], and ship charging applications [12][13][14].…”

“…Moreover, they investigate the seawater at the MHz frequency range and separation distance between the couplers up to 180 mm. In contrast, Mahdi et al study the CPT system's maximum available efficiency and power using a conjugate matching approach and consider the dissipative losses of the seawater [14]. The main contributions of this paper are:…”