Improving the Misalignment Tolerance of Wireless Power Transfer System for AUV with Solenoid-Dual Combined Planar Magnetic Coupler

Abstract

In order to solve the problem of power transmission efficiency reduction resulting from misalignment in the Wireless Power Transfer (WPT) system for Autonomous Underwater Vehicle (AUVs), a novel coupling structure with strong tolerance to misalignment is proposed. A solenoid coil is selected as the transmitting coil, and the receiving coil is composed of dual combined planar coils. The WPT system can still maintain stable output under uncertain axial misalignments for AUVs. The magnetic field distribution of the proposed magnetic coupling structure is analyzed theoretically, and the distance between the coils in the dual combined planar receiving coil is optimized. The theoretical analysis shows that the proposed solenoid-dual combined planar coils coupling structure can effectively maintain a stable mutual inductance between the transmitting coil and receiving coil under different axial misalignments compared with solenoid-unipolar planar coil coupling structure. An S-S resonant compensated WPT experimental prototype is built to verify the output characteristics of the proposed magnetic coupling structure. Compared to the magnetic coupler with the unipolar planar coil, it is validated by experiment that the proposed magnetic coupler substantially enhances the stability of power transmission efficiency and output power when axial misalignment occurs. The power transmission efficiency decreases by 6.74% when axial misalignment increases from 0 to 40 mm in saltwater. Meanwhile, the variation of output power is less than 4.15%.

Wireless Power Transfer for Unmanned Underwater Vehicles: Technologies, Challenges and Applications

“…In 2023, a coaxial and planar hybrid prototype was proposed by Wen et al [199]. Here, a solenoid transmitter was tested with a dual planar receiver, achieving an efficiency of 85% for a 401 W power transfer without misalignment.…”

Experimental Results and Analysis of Midrange Underwater Asymmetric Wireless Power Transfer

“…So, in order to explore the transfer characteristics at midrange, a dual-coil WPT system with a series-series topology at a resonant frequency of 460 kHz is constructed. The circuit topology of this WPT system in air is shown in Figure 2, where U s is the excitation voltage source; I 1 is the current of the primary coil; L 1 and C 1 are the inductance and capacitance of the primary coil, respectively; I 2 is the current of the secondary side; L 2 and C 2 are the inductance and capacitance of the secondary side, respectively; M 0 is the mutual inductance between the primary and secondary coils in air; R L is the load resistance of the secondary side, which, considering that the actual battery internal resistance is 10-100 Ω [31,32] and taking into account the specific conditions of the laboratory, is set to 44.4 Ω; R B is the balancing resistor, wherein when R B = R L holds, the primary and secondary circuits are symmetrical, but otherwise, the circuits are asymmetrical; R p1 is the internal resistance of the primary coil, the capacitance, and the power amplifier output resistor; and R p2 is the internal resistance of the secondary-side capacitor and coil. In this study, an asymmetric circuit structure is constructed by decreasing the primary-side resistance so that the impedances on both sides of the circuit are not equal.…”

“…The load resistance is variable generally: e.g., the actual battery internal resistance changes usually from 10 Ω to 100 Ω [31,32]. The transfer characteristics under different load resistances are explored with a transfer distance of 50 cm, and a frequency of 400 kHz.…”

A Comprehensive Review of Developments in Electric Vehicles Fast Charging Technology

“…These systems are more efficient and compatible with electric vehicles. However, in wireless EV charging, misalignment between the transmitter and receiver coils can lead to fluctuations in the coupling coefficient, reducing the system's efficiency and power output [50]. Researchers are working to address misalignment issues in static WPT systems [50][51][52][53].…”

“…However, in wireless EV charging, misalignment between the transmitter and receiver coils can lead to fluctuations in the coupling coefficient, reducing the system's efficiency and power output [50]. Researchers are working to address misalignment issues in static WPT systems [50][51][52][53]. These systems typically have two stages: a high-frequency inverter converts input power to AC, which is then transferred to the primary coil to create an electromagnetic field.…”