Abstracts:The affiliation for author “Dan Zhou” in the paper [1] was erroneously listed as including the “State Key Laboratory of Electrical Insulation and Power Equipment, Xi'an Jiaotong University, Xi'an 710049, China.”

Abstracts:This article presents a highly integrated and compact hybrid wireless power transfer (WPT) system with asymmetrical printed-circuit-board (PCB) based self-resonators. The PCB-based self-resonant coupler consists of four PCB-coil plates with two different sizes, which can work as the transmitter/receiver for inductive power transfer as well as the capacitive plates for capacitive power transfer. With a typical stacked four-plate configuration, both inductive and capacitive mutual couplings are achieved between transmitter and receiver, contributing to a highly compact and integrated self-resonant hybrid WPT system without any external compensation components. Detailed theoretical analysis and system modeling are provided based on the two-port parameter theory and a 300 W hybrid WPT prototype is implemented with an asymmetrical coupler consisting of 210 and 140 mm PCB-coil plates. The implemented hybrid WPT system is tested at 80, 60, 37, and 12 mm with self-resonant working frequencies of 3.845, 3.75, 3.57, and 3.19 MHz, respectively, and the system performance in terms of output current property, power transfer capability, dc–dc efficiency, and misalignment tolerance are evaluated in details, which demonstrate a peak dc–dc efficiency of 87.3% with 155.7 W at 12 mm and 86.7% with 237.5 W at 37 mm, validating the effectiveness of the designed hybrid WPT system.

Abstracts:Dynamic wireless charging provides a novel solution for extending the range of electric vehicles, but requires stable power transmission to maintain reliability. To reduce dynamic driving power fluctuations, this article proposes a design for staggered bipolar (SBP) transmitter track with a corresponding X-type receiver for electric vehicles. Through a staggered magnetic field configuration, the proposed SBP structure supports interoperable coupling with appropriately sized bipolar receiver oriented for traveling or lateral coupling. When paired with the X-type receiver, only a uniphase receiver is sufficient to achieve smooth traveling power output across full lateral misalignment range and track module spacing up to 50% of one transmitter length, without requiring additional auxiliary coils or circuitry. A 3.3 kW dynamic prototype was built based on the designed magnetic coupler and circuit parameters. Experimental results show that, without increasing width, by adjusting the pole shoe positions, the X-type receiver can adapt to SBP track module spacing of up to 125 mm, with output voltage fluctuation kept below 2.83% during aligned motion, and dc/dc efficiency reaches 91.04%.

Abstracts:In the realm of output control for wireless power transfer (WPT) systems, variable frequency (VF) regulation of the transmitter inverter stands out as a leading and sophisticated research direction, as it facilitates the adjustment of the voltage conversion ratio and holds significant promise for long-distance power transfer applications. However, the VF regulation process in WPT systems is characterized by strong nonlinearity and is highly sensitive to variations in the inverter driving frequency. In addition, increasing transfer distances exacerbate these nonlinearities due to changing mutual inductances. Consequently, traditional approaches to VF regulation are constrained by a limited operating range, which impedes the application of WPT technology in scenarios involving varying distances. To address these challenges and enhance the system's adaptability to different power transmission distances while managing multiparametric uncertainties in WPT systems, this article develops a data-driven model-free adaptive control (MFAC) method. Initially, an online modeling approach utilizing dynamic linearization is proposed to characterize the VF regulation process using solely system input–output data. Subsequently, a switched control strategy based on the estimated data model is devised to calculate the optimal operating frequency for the WPT system. Finally, a prototype with maximum output of 3.88 kW is constructed to demonstrate the feasibility of the proposed approach. The results indicate that the data-driven control system exhibits a robust dynamic response and strong resilience across varying transfer distances ranging from 5 to 65 cm, corresponding to a distance–diameter ratio of 0.125–1.625.

Abstracts:The dynamic wireless power transfer (DWPT) system with a two-phase bipolar narrow rail has the advantages of low power fluctuation and large lateral tolerance. Traditional two-phase systems not only feature numerous magnetic cores and windings, but also have shortcomings in power loss and power density. Due to the use of a dual full bridge inverter, its number and control of switching devices are also complex. A high power density and low loss DWPT two-phase rail with II-type ferrite magnetic tooth and interval lap winding is proposed to improve power loss and power density. A circuit topology and control method with a three-leg inverter is used to simplify the system. The models of circuits and magnetic circuits are analyzed, and simulations and experiments are conducted. The proposed two-phase transmitter has a 38.5% reduction in wire usage and a ferrite core volume decrease of 31%, while the coupling coefficient increases by 37.9%. Experimental results for a 10-kW system show that the transmitter loss of the two-phase magnetic coupler is 30% lower than that of the single-phase transmitter. At 10 kW power output, the dynamic efficiency of the system from dc to dc maximum efficiency is 87%, and the mean efficiency is 84%. A typical location dc to dc system efficiency is 86%, the magnetic coupler efficiency is 90%. The results indicate a significant improvement in power density and power loss. This article is accompanied by a video of the system dynamic charging.

Abstracts:Wireless power transfer (WPT) technology provides an effective solution to the power supply of autonomous underwater vehicle (AUV). However, the misalignments and rotation often occur between the docking station and AUV, which would result in a fluctuation to system's output characteristics. To maintain constant current output with unreliable communication under seawater environment is a barrier. Aiming at this problem, this article presented an LCC-N WPT system with fewer compensation devices on the receiver side, which is immensely suitable for reducing the weight and volume of the AUV. Meanwhile, based on the switch-controlled capacitance (SCC) technology and frequency modulation at the transmitter side, the mentioned WPT system could stabilize the output current while the coupling coefficient k and load resistance $R_{L}$ undergo a wide range variation. The determination method of system parameters, including operation frequency, capacitance value of SCC and compensation inductance under various misalignment conditions was detailed derived. Besides, the zero phase angle characteristic could be achieved during the whole process. The experimental results indicate that while the coupling coefficient varies from 0.3 to 0.54, the fluctuation of output current for the proposed WPT system is less than 4.47% and the power transfer efficiency could be maintained above 87%, and the maximum efficiency can reach 92.8%. In addition, the characteristics of load-independent output current during the misalignment process was also verified.

Abstracts:In many application scenarios, inductive power transfer (IPT) converters are expected to be compact and lightweight, especially in the charging device side. The unilateral compensation is an effective solution to eliminate the bulky passive inductors and capacitors. However, most existing unilateral compensation topologies in IPT converters cannot achieve multiple design objectives simultaneously, such as unity power factor (UPF), load-independent constant output, soft switching, and so on. This article starts from a generalized transformer model and proposes the design principle for unilateral compensation networks in terms of flexible constant-voltage or constant-current output while combating the parameter constraint of the given loosely coupled transformer. In addition, the near UPF and soft switching can be simultaneously achieved to improve the transfer efficiency. Based on the design principle, a family of unilateral compensation topologies is proposed and the design process is detailed. Finally, a 100-W prototype of CLC-N(none) compensated IPT converter is built to verify the design.

Abstracts:The dynamic wireless power transfer (DWPT) system is an ideal solution for electric vehicles as it can maintain the power supply and reduce the battery volume. However, its adoption in electric vehicle charging has been limited due to the high installation costs, low charging efficiency, and significant power fluctuations. To address these issues, a repeater-based DWPT system with a controllable detuning rate method is proposed to achieve constant output power during movement. The switch-controlled capacitor is introduced in the repeater coil to adjust its detuning rate dynamically. Based on the relationship between the output power and the mutual inductances among the active, repeater, and receiver coils, the detuning rate is controlled to reduce power fluctuations. Moreover, increasing the detuning rate under no-load conditions reduces the losses in the repeater coil. A down-sized experimental prototype of the proposed DWPT system was built, and the experimental results show that it can maintain output power with fluctuations of less than 4.8% and an efficiency of approximately 85% throughout the dynamic process. Furthermore, constant power output is maintained even when the mutual inductance between the repeater coil and the active coil varies by up to 25%.