Dynamic wireless charging (DWC) systems have emerged as a highly promising solution to enhance the convenience and efficiency of electric vehicle (EV) charging. In this paper, we present a novel Multiple-Input Multiple-Output coils-based DWC (MIMO-DWC) approach, conducting a discrete analysis model of the continuous dynamic wireless charging process while aiming to improve the performance and reliability of MIMO-DWC systems. By integrating MIMO coils with traditional inductive power transfer (IPT), the proposed system theoretically attains a notably higher power transfer efficiency and remarkable spatial flexibility, effectively reducing alignment sensitivity and significantly enhancing the robustness of the charging process. The simulation results indicate that under a reasonable coupling coefficient, the MIMO-DWC system can achieve a maximum power transfer efficiency 84.5%, surpassing that of the Single-Input Single-Output (SISO) DWC system 62.5%, with experimental validation carried out to firmly confirm the feasibility and effectiveness of the proposed method.

This paper presents a domino wireless power transfer system designed to provide flexible constant-voltage (CV) output in each relay unit. Importantly, the voltage level of each CV output can be independently and flexibly preconfigured, establishing a reconfigurable output paradigm. The core innovation lies in the use of an inductor-capacitor-capacitor-series (LCC-S) compensation network in each relay unit, allowing for the intentional design of compensated inductance and mutual inductance to achieve various CV lift ratios. Additionally, four typical CV scenarios are thoroughly analyzed: constant, monotonically increasing, monotonically decreasing, and high-low jumps. Finally, an experimental prototype has been developed, and additional measured waveforms will be presented to demonstrate the effectiveness of the proposed system.

Inductive power transfer (IPT) systems conventionally operate at the natural resonant frequency for efficient power transmission, but their output power is sensitive to mutual inductance changes. Recent studies have shown that parity-time-symmetric IPT systems have two splitting frequencies in the strongly coupled range, enabling robust wireless power transfer with constant output power and high efficiency. Self-excited oscillation circuits can automatically track these optimal frequencies without measuring circuit parameters. However, practical self-oscillating systems contain voltage harmonics and feedback delays, which are often ignored in the analysis of steady-state performance. In this paper, the effects of high-order harmonics and time delay on steady-state frequencies are systematically analyzed. First, the formula of ideal bifurcation frequency is derived based on the zero-phase-angle condition. Then, steady-state conditions under square wave voltage and feedback delays are obtained using the Fourier series and superposition theorem. Finally, numerical examples demonstrate that exceptional points shift towards stronger coupling due to harmonics, whereas time delay could eliminate frequency bifurcation.

In this paper, a robust closed-loop speed control for wireless motor systems is proposed with the consideration of maximum efficiency point tracking (MEPT). Firstly, the optimal load condition for maximum efficiency point tracking of wireless motor systems is derived, a buck converter with an optimal duty cycle is adopted to achieve impedance match of the wireless power transfer system such that maximum efficiency can be guaranteed. Then, an integral fixed-time sliding mode (FTSM) control strategy is designed to achieve robust speed tracking control for wireless motors in the presence of parameter variation and external disturbance. The simulation results illustrated superior tracking performance with 15.90% speed tracking overshoot reduction, 26.90% speed tracking error RMS reduction compared with the conventional PID control. And the efficiency of the WPT systems is well maintained at 85.55% simultaneously.

In a wireless power transfer (WPT) system, maximum efficiency can be achieved at specific load conditions by employing impedance matching (IM). Some researchers employ DC-DC converters or additional inductors and capacitors; however, this inevitably leads to an increase in both system cost and complexity. In this paper, we propose a receiver-side variable capacitor system, which comprises a series-connected switch-controlled capacitor (SCC) and a parallel-connected relay-controlled capacitor (RCC). This system aims to achieve maximum efficiency tracking (MET) for WPT across a wide range of load variations. The proposed system autonomously detects variations in the load and adjusts the equivalent capacitor value to achieve MET. Experimental results demonstrate that the proposed system can enhance system efficiency by approximately 5% to 20% when the load varies from 60 Ω to 180 Ω. Finally, we validate the feasibility of the proposed system through experimental verification.