In order to adapt to the single power supply system of the aircraft, this paper proposes and investigates a novel dual-winding fault-tolerant (DF) motor drive system based on the redundancy bridge arm for aerospace applications. The proposed DF motor offers the advantages of magnetic isolation, physics isolation, thermal isolation, small cogging torque ripple, inhibiting the short circuit current and high fault tolerance. The proposed DF motor drive can adapt to the single power supply system of the aircraft, reduce the drive cost, and reduce the number of independent power sources and power switches. In addition, it can improve power density, the reliability and the utilization rate of the drive. At the same time, the drive system has stronger fault-tolerant ability and it can achieve the fault tolerant control for one phase winding fault or multiphase windings fault. To realize the short-circuit fault diagnosis performance, the short-circuit fault diagnosis and processing method has been investigated. Then, to realize the fault-tolerant performance, a novel SVPWM fault-tolerant control strategy is proposed. Finally, the DF motor drive performances have been verified by experiments. The research results verify the reliability and effectiveness of the proposed DF motor drive system and SVPWM fault-tolerant control strategy.

In this paper, the implementation of a single-stator double-rotor fractional-slot concentrated-winding (FSCW) axial-flux permanent-magnet (AFPM) machine are presented to verify a simple and reliable structure design and oil-immersed cooling of the stator with modular soft magnetic composites (SMC) core. Due to the yokeless and segmented stator, the process of embedding the windings into the stator teeth will probably become simpler. By preforming rectangular copper wire, the shorter end-winding length and higher fill factor can be achieved. In order to eliminate eddy-current losses and manufacturing costs, the fiberglass epoxy is used for the supporting components of the fixation for modular SMC stator and PMs, which is a non-magnetic and non-conductive material. Hence, the robustness of stator and rotor are taken into account due to the stator modularity weakening effect on strength. Meanwhile, a fully sealed stator with oil-immersed cooling is proposed to enable the current density with 20 A/mm2 in the armature windings for stable operation. The electromagnetic property, including in magnetic field distribution, torque capacity and flux-weakening ability, are performed based on the three-dimensional (3-D) finite element analysis (FEA), as well as the mechanical performance. The coupled thermal and computational fluid dynamics (CFD) model is built to predict the flow and temperature distribution inside stator with oil immersed forced cooling. The construction and experimental verification of a full-scale 30kW prototype are elaborated to verify the predicted performances in terms of torque density, structural strength and cooling.

For wireless charging of electric vehicles (EVs), increasing the output power level is particularly important. In this paper, the purpose of improving the output power while maintaining optimal transmission efficiency is achieved by optimizing the parameters of the compensation topology under the premise that the coupled coils of the system does not need to be redesigned. The series-series (SS) and hybrid-series-parallel (LCC, composed by an inductor and two capacitors) compensation topology are studied. The influence factors of load resistance to achieve optimal efficiency, the influence of LCC compensation parameters on the power output level, and the influence of parameter changes on system safety are analyzed. Theorical results show that by rationally designing the LCC compensation parameters, larger output power and optimal transfer efficiency can be achieved under different load resistance by adjusting the inductances of the primary and secondary compensation circuits. The output power of the optimized system with adjusted LCC compensation topology is increased by 64.2% with 89.8% transfer efficiency under 50 ohms load in experiments. The correctness and feasibility of this parameter design method are verified by both theorical and experimental results.

With the rapid development and extensive application requirements of wireless power transfer (WPT) technology, the common symmetrical WPT system is growing more mature, but it may still struggle to meet the vast demands. When the WPT system has a long transmission distance and the dimensions of transmitter and receiver coil are asymmetric, the current in the transmitter coil of traditional two-coil symmetrical structure may be excessive. The addition of a relay coil between the transmitter and the receiver coil can effectively reduce the current of transmitter coil, thereby improving system efficiency and reducing electromagnetic field (EMF) leakage. In this article, the parameters of relay coil are optimized by theoretical calculation and multiobjective genetic algorithm. The results show that the optimized three-coil system can reduce the current of transmitter coil by 73.1%, improve the efficiency by 10.7%, and suppress the EMF leakage by 12 dB simultaneously. Finally, the effectiveness of the proposed system is verified by experiments.

This study aims to solve a problem that exists with impedance matching networks in terms of extra cost and power loss of electronic components in a four-coil wireless power transfer (WPT) system using class E power amplifier as power supply, which is not conducive to the improvement of system efficiency and output power. A design method of sharing the resonant inductor in class E power amplifier and the excitation coil in the four-coil WPT system is proposed. This method comprehensively considers the output power and transfer efficiency of the system, the number of coil turns, coil size and many other factors. Compared with the traditional four-coil system using a class E power amplifier as a power supply, the proposed method simplified the system structure by leaving out a resonant inductor and load matching circuit, which can reduce the power loss of system and improve efficiency. Moreover, the precisely tuning of resonant inductor was not necessary, which improved the stability of the system. The correctness and feasibility of the parameter design method were verified by experiments. The experimental results showed that the output power of the system was increased by 18.7%, the efficiency was increased by 11%, and the transmission distance was up to 0.7 m, which is suitable for wireless power supply of electronics and sensors.

This paper investigates the tapered and curved coil used in wireless power transfer (WPT) system for the purpose of improving flexibility in specific applications. The WPT transmission performance is always declined by coil bending. To solve this problem, the models of the coils are built and their magnetic flux are analyzed. The phenomenon of curvature angle splitting is researched, the mechanism is revealed and the method is proposed to avoid the splitting. Formulas are derived to determine whether the system is working in curvature angle splitting state. By optimizing the coil parameters to make the system work in critical splitting state, the maximum output power and excellent stability under different angles are achieved. Experimental results show that when the optimally designed receiver coil is bent in the range of 50° to 130°, the maximum current change rate is only 4.3%. The study in this article will further promote the application of wireless power transfer technology in a wider range of fields.