No abstract

The wireless power transmission (WPT) of an autonomous underwater vehicle (AUV) tends to have non-negligible eddy current loss with increasing frequency or coil current due to the conductivity of seawater. In this paper, the inductor-capacitor-capacitor and parallel (LCC-P) topology and the magnetic coupler with an H-shaped receiver structure are chosen to achieve a compact system on the receiving side. The conditions for constant current output of the LCC-P topology are analyzed based on the cascaded circuit analysis method. The traditional parameter design method does not consider the influence of eddy current loss on the system circuit model, by introducing the equivalent eddy current loss resistance at both the transmitting side and receiving side, a modified circuit model of the WPT system in the seawater condition was obtained. Afterward, a nonlinear programming model with the optimal efficiency of the constant current mode as the objective function is established, and the genetic algorithm is used to obtain the optimal system parameters. An underwater AUV-WPT prototype was built and the finite element simulation and experimental results verified the theoretical analysis.

Inductive power transmission technology provides a new way to solve the energy problem of autonomous underwater vehicles (AUVs). The performance of the magnetic coupler determines the system transfer capacity. A novel open-type magnetic coupler with a simple structure, lightweight, strong anti-misalignment performance and high self-inductance stability is proposed for the arc-shaped shell of AUV. The proposed magnetic coupler employs an arc-shaped transmitter and the receiver uses an H-shaped ferrite core to realize the close coupling of magnetic flux in the vertical direction. The parameters of the magnetic coupler are optimized based on ANSYS Maxwell simulation, which ensures its coupling performance and anti-misalignment performance while minimizing the volume and weight of the receiver. To verify the proposal, a wireless charging system with a 183.9 g receiver is built. The maximum self-inductance change rate of the coil and maximum coupling coefficient change rate under the conditions of axial misalignment from −25 mm to 25 mm and rotational misalignment from −10 • to 10 • are 2.9% and 14.3%, respectively. In the case of full alignment, it can deliver 735.6 W at a DC-DC efficiency of 90.87%.

No abstract

In order to achieve efficient operation of WPT systems, the conventional direct impedance matching method that requires mutual inductance and load identification is often used, which makes the system complicated. In this paper, an indirect impedance matching method without parameter identification is proposed, especially for systems with large coupling factor and load variations. This method is based on the characteristic that the optimal voltage gain of the resonator is only related to its inherent parameters, and impedance matching can be achieved by controlling the voltage gain in real time. To further improve the efficiency of the system, a single-sided detuning design method is used to achieve soft switching of the inverter. Based on the optimal voltage gain expression derived by using both the indirect impedance matching method and the single-sided detuning design method, a compound control strategy for a series-series-compensated topology with dual-side power control is proposed to improve efficiency and stabilize the output voltage. A hardware prototype is built and a peak DC-to-DC efficiency with the optimal output resistance at about 28.9Ω is 91.58%. When the output resistance is 100Ω, the efficiency improved by 7% after using the proposed strategy.