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In this article, a design method of the double-D (DD) coil aiming at high misalignment tolerance is proposed, and the electromagnetic field (EMF) shielding of the system is considered. Inspired by the DD coil recommended in the standard J2954 published by the Society of Automotive Engineers, the novel structures of the transmitting (Tx) coil and the receiving (Rx) coil are designed, respectively. First, the standard DD coil is introduced as a reference. Second, for the Tx coil, the parameters, such as length, width, and coverage, are investigated in detail. For the Rx coil, the coil structure overlapped in the edge is optimized. The purpose is to obtain a higher coupling coefficient at the maximum offset. Third, considering EMF emissions exceeding the limit, the structure of the central-depressed coil with E-shaped cores is proposed in the Tx coil. The EMF emissions can be reduced to less than 27 μ T at the rated output power. Finally, a 6.6–kW experimental system of which the maximum transmission efficiency is higher than 94% is set up. The experimental results prove that the proposed structure is beneficial to maintain a higher coupling coefficient against misalignment and suppress EMF emissions.

Three-phase meander-type dynamic wireless power transfer is ideal for the power supply or charging of rail vehicles. However, there is a lack of systematic analysis and design of the three-phase receiver. To achieve the compact design of the three-phase receiver in practical applications, this article studies the compact three-phase receiver with overlapped receiving coils and ferrite core. Based on the analysis of the fundamental coupling characteristic of three-phase meander-type dynamic wireless power transfer, two overlap modes of the receiving coils are concluded and compared. Meanwhile, by considering the influence of mutual inductance harmonic distortion, the accuracy of the receiving coil analysis and design is improved. Furthermore, a practical distributed strip core design is presented to enhance the coupling between transmitting coils and receiving coils. Additionally, the effect of the core on coupling imbalance is analyzed in detail and proves to have little effect on the power transfer. Afterward, a design flow of star-connected series-compensated receiver with the overlapped coils and the distributed strip core is proposed. Finally, for verification, a small prototype with an average output power of 154 W and average efficiency of 97% of the receiving coils is established.

Dynamic wireless power transfer (DWPT) technology shows a vast development prospect for EV application, with advantages of reducing the demand for battery capacity and improving the user experience. However, the need to improve output performance leads to a challenge in receiver design with limited space and allowable load on the EV side. In this paper, a design of a dual-phase non-salient pole (NSP) receiver for the EV DWPT system with bipolar transmitter is proposed, aiming at providing a solution to the contradiction between reducing the volume or cost and improving the misalignment tolerance of the receiver. The coupling principle of the proposed receiver is analyzed. The structure parameters are optimized by the finite-element simulation method. Combined with specific design indexes, it is proven by comparison with the existing dual-phase receiver that the proposed receiver is 35.4% smaller in volume and needs 47.0% shorter wires. Moreover, the significant advantage of the proposed dual-phase NSP receiver in misalignment tolerance is verified by simulations and experimental comparisons.

In this paper, a novel magnetic coupler of wireless power transfer system for the solar wing driving of the spacecraft is designed. Compared with the traditional slip-ring power supply, the proposed magnetic coupler is characterized by non-contact, high efficiency, wear free, safety, and reliability. Particularly, it can be applied to the rotating condition. To realize light weight and small volume of the receiver, the magnetic coupler has been optimized from both compensation topology and coil configuration. First, a series-none topology is employed to eliminate the bulky secondary-side compensation capacitor. Second, a new nested solenoid coil with strip core is proposed to ensure miniaturization, stable power transfer, and high efficiency. Finally, the experimental setup is built to verify the performance of the designed magnetic coupler. Experimental results are well matched to simulations, demonstrating that the weight of the prototype is 1.3 kg and the transfer power is 3 kW at an ac–dc efficiency of 92.7%.

In this article, a design of bipolar nonsalient pole (BNSP) transmitter, which originates from motor theory, for high-power EV dynamic wireless power transfer (DWPT) system is proposed. To analyze and evaluate BNSP transmitter in aspect of principle, characteristic, and performance, the existing I-type, S-type, and N-type transmitters in DWPT application are classified as bipolar salient pole (BSP) transmitter, which establishes a reference for comparing. The design parameters and other contrast conditions of BNSP and BSP transmitters are given. Coupling flux and leakage flux of BNSP transmitter are analyzed by comparing the magnetic models and the finite-element models of BNSP and BSP transmitters. Based on the modular design in practical application, the sensitivity of coupling performance to the module gap in BNSP and BSP transmitters is analyzed and compared in simulation. All theoretical results are verified by contrast experiments. The maximum effective mutual inductance of BNSP transmitter is about 31.0% larger than that of BSP transmitter, and the efficiency of the system with output power of 10 kW is 93.5% with BNSP transmitter, about 2.4% higher than that with BSP transmitter. Besides, BNSP transmitter needs 5.9% shorter Litz wire and 53.1% smaller volume of cores, which makes it smaller in size.

The system efficiency and charging current highly dependents on load conditions, which varies in a wide range for practical applications, such as the supercapacitor charge. To achieve the maximum system efficiency (MSE) tracking and constant current (CC) charging, this paper designs the dual-side controlled wireless power transfer (WPT) system. The fundamental harmonic analysis based on the mutual inductance model is built to illustrate the system characteristics. Based on the algorithm of perturbation observation, the primary-side Buck converter realizes the MSE tracking through measuring the minimum system dc input current. The secondary-side PI controlled semi-active rectifier achieves CC charging for the supercapacitor. The simulation results verify the proposed control method. During the CC charging of 2 A, the system efficiency is significantly improved.

In this letter, a novel two-coil magnetic communication method based on magnetic resonant coupling and frequency divarication is proposed. The half-power decay is employed to derive the boundary condition of double 3-dB bandwidths. Moreover, the expressions of load power, power ratio, and communication capacity are deduced based on the mutual inductance theory. The theory proves that there exists one common peak value for the bandwidth and communication capacity. Also, the expression of peak value of the maximum capacity is derived using the boundary condition. The experimental results demonstrate that the proposed magnetic communication method has a maximum bandwidth and communication capacity at a wide frequency range, especially at low frequency.

Dynamic magnetic coupling resonate wireless power transfer (WPT) system with single magnetic pole track allows very limited lateral migration of the power receiver relative to the power supply rail. The multi-pole rail improves the issue of lateral migration effectively, but when the receiver moves along the rail, the null points make it difficult to be applied to the equipment which carries none energy storage component. This paper presents a new multiphase receiver cooperating with multipolar power supply rail, which can improve the power transferring stability. Enabling applications such as automatic guided vehicles, robots, electrical vehicles which require continuous power supply, and ensure them to work continuously without any energy storage component. Besides, the improvement is achieved with any kind of shape of bipolar or multipolar tracks.