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This paper proposes a novel inductive and capacitive combined wireless power transfer (IC-WPT) system for unmanned aerial vehicle (UAV) applications. First, a new compact inductive and capacitive combined coupler is presented. The magnetic field coupled power transmission of the compact coupler contains one magnetic transmitting unit, which is composed of two biorthogonal L-type cores and two rectangular coils wound on each of the short edges of the L-type ferrite core in the vertical position, and two air-cored receiving coils embedded in the legs. Meanwhile, the electric field coupled power transmission of the compact coupler consists of four pieces of copper foil, where two are attached on the primary side and two are attached on the secondary sides for wireless energy transmission through capacitive coupling. Second, a simple resonant compensation network is developed for the IC-WPT system. To make the secondary side lightweight, the receiver self-inductance of the inductive power transfer (IPT) coupler and compensating capacitance of the capacitive power transfer (CPT) receiver can be used to compensate each other. A prototype of the proposed UAV IC-WPT system is built and tested. Experimental results show that the wireless power transfer system can deliver 130 W at an efficiency of 81.2%, which means it can be adopted to the autonomous charging of UAVs. [ABSTRACT FROM AUTHOR]

This paper presents a new rotor shape design with optimum reverse 3rd harmonic for wound field synchronous machines to effectively enhance the saliency ratio and reduce the torque ripple in a micro electric vehicle traction system. Due to the enhanced saliency ratio, the reluctance torque is expected to be improved. The air gap flux density distribution is reshaped by the new rotor shape method, which benefits the low torque ripple. By contrast, the reverse 3rd harmonic injection is much more suitable than the general 3rd harmonic injection for increasing the effective air gap length along the q-axis for a high saliency ratio. Subsequently, three amplitudes of the reverse 3rd harmonic are studied and it is found that the optimum reverse 3rd harmonic is 1/6 of the fundamental one. To verify the effectivity of the proposed design, the original model and the ICS model are compared. Finally, all the motor characteristics, such as back electromotive force, cogging torque, and electromagnetic torque, are predicted using a 2-D finite-element method with the aid of JMAG-Designer. [ABSTRACT FROM AUTHOR]

The paper proposes a hybrid-excited wound field synchronous machine (HE-WFSM), which can achieve high reluctance torque utilization. The key of the proposed HE-WFSM is that two permanent magnets (PMs) assist each rotor pole in forming an additional magnetic flux circle. It is opposite to the magnetic flux circle along the q-axis in the WFSM. The reduction of the q-axis flux can help to improve the saliency ratio and reluctance torque. Additionally, the asymmetrical flux linkage achieves a closest current phase angle between the maximum field torque and the maximum reluctance torque. To highlight the advantages of the proposed HE-WRSM, a general WFSM was adopted as the basic machine and analyzed under the same operating conditions. All performances of the basic machine and proposed HE-WFSM were predicted using finite element analysis (FEA) in Jmag-Designer. Finally, it was confirmed that the proposed HE-WRSM can achieve high reluctance torque utilization. [ABSTRACT FROM AUTHOR]

This paper proposes an optimal design for a salient pole wound field synchronous machine (WFSM) with a single flux barrier to improve torque performance and obtain a wide operating range, simultaneously. The proposed WFSM motor can effectively decrease q -axis inductance to improve the saliency ratio ( X_{d}/X_{q}) and increase the reluctance torque. To maximize the saliency ratio and improve the torque characteristics, the single flux barrier is optimized, considering the magnetic saturation that uses Kriging method based on Latin hypercube sampling and a genetic algorithm. The 2-D finite element analysis results by the aid of JMAG-Designer shows that the saliency ratio X_{d}/X_{q}$ , the reluctance torque, and the total torque of the optimal model are increased by 9.27%, 20.45%, and 6.17%, respectively, compared with those of the basic model. Finally, the performance of the optimal motor is verified through an experimental test, which indicates good agreement with the simulation results. [ABSTRACT FROM AUTHOR]

Autonomous underwater vehicle (AUV) is a key mobile node in the ocean observation network. However, the limited endurance capacity and limited cruising range have become the bottlenecks in the wide application of the AUVs. In order to extend cruising range, this article develops a uniform power inductive power transfer (IPT) system for AUVs. A novel magnetic coupler with a low output fluctuation, low weight of receiver and a low space occupation of the AUV is proposed in this article. The proposed magnetic structure employing a quadruple-coil transmitter and a crossed dipole receiver utilizes uniform horizontal magnetic flux to establish stable coupling against rotational and axial misalignment. An IPT circuit topology is designed and analyzed in detail, meanwhile, the phase difference of the excitation currents is optimized to achieve the power and efficiency stability versus misalignments. The proposal is analyzed, established, and tested in this article. The magnetic receiver weighs only 414 g. The results show that the prototype can deliver 964.7 W with a dc–dc efficiency of 90.9%. In the process of rolling dislocation from –20° to 20° and axial dislocation from –30 mm to 30 mm, the maximum fluctuation of output power is 12.1% and 20.2%, respectively. [ABSTRACT FROM AUTHOR]

This paper presents the design and optimization of a novel wound field synchronous machine topology, in which permanent magnets (PMs) are introduced into the rotor slot opening with segment configuration for high quality output torque performance. The rotor shape of the proposed PM-assisted wound field synchronous machine with segment configuration is optimized for maximizing the average output torque and decreasing torque ripple under constant PM volume and motor size. The segment configuration can be benefit to improve the reluctance torque. In addition, it is further clarified that the assisted-PM can help to increase the field torque by enlarging the magnetizing synchronous reactance (Xf), as well as increasing airgap flux density. An optimal method combining Kriging method and genetic algorithm is applied for rotor shape optimization of proposed PM-assisted wound field synchronous machine (PMa-WFSM). Then, the 2-D finite-element analysis results, with the aid of JMAG-Designer, are used to confirm the validity. It is determined that the average output torque is improved by 31.66%, and keeps lower torque ripple without decreasing efficiency, increasing PM volume and motor size compared with those of the basic model. Finally, irreversible demagnetization and mises stress analysis verifies the reliability of the novel topology. [ABSTRACT FROM AUTHOR]

This paper presents an optimal design for a surface-mounted permanent magnet (SPM) motor to suppress torque pulsations and save the magnet cost, by using multi-grade permanent magnets. Based on a conventional SPM motor with single-grade bonded NdFeB magnets, the proposed SPM motor is designed with two-grade bonded NdFeB and one-grade ferrite magnets, and then optimized by combining the Kriging method with a genetic algorithm, for further minimizing torque pulsations and saving the magnet cost by maintaining the high average torque. As a result, the cogging torque, torque ripple, and magnet cost of the optimized SPM motor are highly reduced compared to those of the conventional SPM motor. Furthermore, the optimized SPM motor is verified to have superior endurance against the magnet’s irreversible demagnetization within three times of the rated current excitation. All motor characteristics, including airgap flux density, cogging torque, electromagnetic torque, and demagnetization ratio are first predicted with the aid of a finite-element method. Finally, the optimal design and analysis results are validated by the experimental results. [ABSTRACT FROM AUTHOR]

In this paper, a misalignment-tolerant wireless charging system based on multidimensional cross-coupling for autonomous underwater vehicles (AUVs) is proposed. The four transmitting coils of the proposed system magnetic coupler are divided evenly into two pairs as bipolar transmitting units. Subsequently, the uniform multi-dimensional horizontal magnetic flux can be obtained by two current vectors with a 90° phase difference exciting in the bipolar transmitting units. For the receiver, a couple of orthogonal coils are designed to form cross-coupling with the transmitter to pick up the maximum magnetic flux. Then, the proposed magnetic coupler combined with the proposed transmitter and receiver is designed through finite element analysis. Finally, a 900 W prototype is built and tested. Experimental results show that the system has stable output characteristics in the ranges of a − 20° to 20° rolling misalignment and a − 30 to 30 mm axial misalignment. [ABSTRACT FROM AUTHOR]

Compact design in receiver and misalignment tolerance are two basic considerations for practical applications of wireless power transfer (WPT) in unmanned aerial vehicles (UAVs). To balance these two requirements, a novel magnetic design with the composite interval-acted parallel- & vertical-flux throw, orthogonal two-dimensional flux pick-up, and power-flow summed output is proposed in this letter. The resulting magnetic structure includes a target-shaped transmitter and two quadrature receivers, and the transmitter consists of four annular-type coils which are magnetized in a bipolar mode, making it possible to form a magnetic field with a parallel- and vertical-flux complementary distribution. Moreover, by integrating two orthogonal receiving coils into one receiver, a stable summed output current can supply the UAV onboard load with only a small size receiver. A UAV WPT prototype is established based on the proposal. The results show that the prototype can deliver 325 W with a system efficiency of 86%, and especially the variation of the output current is within ±0.76 A for different landing positions and directions. The overall system efficiency is from 87.3% down to 83.1%. [ABSTRACT FROM AUTHOR]

This paper proposes a novel kind of direct-current and alternate-decay-current hybrid integrative magnetization and demagnetization power supplies applied to transformer dc bias treatment based on a nanocomposite magnetic material. First, according to the single-phase transformer structure, one dc bias magnetic compensation mechanism was provided. The dc bias flux in the transformer main core could be eliminated directionally by utilizing the material remanence. Second, for the rapid response characteristic of the magnetic material to an external magnetic field, one positive and negative dc magnetization superimposed decaying ac demagnetization hybrid integrative power supplies based on single-phase rectifier circuit and inverter circuit was designed. In order to accurately control the magnetic field strength by which a good de/-magnetization effect could be achieved, this paper adopts the double-loop control technology of the magnetic field strength and magnetizing current for the nanocomposite magnetic state adjustment. Finally, two 10 kVA transformers and the experiment module of the hybrid integrative power supplies were manufactured and built. Experimental results showed that the integrated power supplies have good de/-magnetization effect and practicability, proving the validity and feasibility of the proposed scheme. [ABSTRACT FROM AUTHOR]

This paper designs three distribution devices for the smart grid, which are, respectively, novel transformer with dc bias restraining ability, energy-saving contactor, and controllable reactor with adjustable intrinsic magnetic state based on the magnetically tunable nanocomposite material core. First, the magnetic performance of this magnetic material was analyzed and the magnetic properties processing method was put forward. One kind of nanocomposite which is close to the semihard magnetic state with low coercivity and high remanence was attained. Nanocomposite with four magnetic properties was processed and prepared using the distribution devices design. Second, in order to adjust the magnetic state better, the magnetization and demagnetization control circuit based on the single-phase supply power of rectification and inverter for the nanocomposite magnetic performance adjustment has been designed, which can mutual transform the material's soft and hard magnetic phases. Finally, based on the nanocomposite and the control circuit, a novel power transformer, an energy-saving contactor, and a magnetically controllable reactor were manufactured for the smart grid. The maintained remanence of the nanocomposite core after the magnetization could neutralize the dc bias magnetic flux in the transformer main core without changing the transformer neutral point connection mode, could pull in the contactor movable core instead of the traditional electromagnetic-type fixed core, and could adjust the reactor core saturation degree instead of the traditional electromagnetic coil. The simulation and experimental results verify the correctness of the design, which provides reliable, intelligent, interactive, and energy-saving power equipment for the smart power grids safe operation. [ABSTRACT FROM PUBLISHER]