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This paper compares the electromagnetic performance of 10-MW superconducting (SC) generators with three different topologies, i.e., iron-cored stator and rotor topology (ISIRT), iron-cored stator and air-cored rotor topology (ISART), and air-cored stator and rotor topology (ASART). The objective is to provide a powerful insight into the advantages and disadvantages of different topologies, and to establish some design guidelines for selecting an appropriate direct-drive SC generator for offshore wind turbine applications. First, the structures of the three SC generator topologies are introduced. Then, the influence of the SC coil cross-sectional area on torque capability is compared. After that three SC generators with different topologies are optimized, respectively, for further comparison, including the active material cost, weight, harmonics in the electromotive force, torque ripple, field harmonics in the SC coil, and forces on the rotor and stator components, etc. It is found that, with the same SC quantity, the torque capability of the ISIRT is much better than that of the other two topologies. However, the advantage becomes less significant when a larger area of the SC coil is employed. The air-gap flux density waveform of the ASART is much smoother than those of the ISIRT and ISART. The torque ripples of the ISIRT and the ISART are much higher than that of the ASART. The field harmonics (both amplitude and frequency) in the SC coil of the ASART are the lowest. For the ISIRT, most of the force on the rotor is acting on the rotor iron, and thus, the SC coil is more likely to be safe from a mechanical performance point of view and the design of the corresponding supporting structure is simple. However, for the air-cored rotor topologies, nearly all the force is acting on the SC coil. For the air-cored stator, the force mainly acts on the armature winding, whereas for the iron-cored stator, it is mainly on the stator teeth. Due to the excellent mechanical performance of iron, the iron-cored stator is therefore more robust. [ABSTRACT FROM PUBLISHER]

This paper proposes a novel dual-channel switched reluctance motor (DCSRM) driven by two 3-phase standard inverters. The key of the proposed DCSRM is its two operational models. For the first operational model (Model I), it works like a 3-phase traditional SRMsupplied by anH-bridge inverter, which is driven by square-wave currents. For the second operational model (Model II), it can be considered as two mutually coupled SRMs that are supplied by sine-wave currents. These operational models are used to overcome different faults, and the corresponding remedial current strategies are proposed to realize fault-tolerant operation. Then, Model I is adopted for power switch fault. Meanwhile, Model II is employed for open-circuit fault. Moreover, the performances of proposed DCSRM are calculated by a finite element, method and the fault-tolerant performances under different fault conditions are verified by cosimulation. Results show that the proposed DCSRM can be used for safety-critical applications by combining the advantages of traditional SRM and mutually coupled SRM. [ABSTRACT FROM AUTHOR]

Inverter-fed induction motors generate large vibration and noise because of the Maxwell electromagnetic stress between stator and rotor, magnetostrictive stress of silicon steel and the harmonics in load current. On the vibration reduction study of motor cores, many researchers kept their eyes on control strategy. However, they did not compute stress of inverter-fed induction motor under sinusoidal and harmonic excitations. The nonoriented silicon steel in motor cores shows remarkably anisotropic magnetization and magnetostrictive properties under sinusoidal and harmonic excitations. Thus, in order to compute motor stress accurately, anisotropic magnetic properties must be considered. First, anisotropic property of silicon steel under sinusoidal and harmonic excitations is tested to support the stress computation. Then, an electromagneto-mechanical coupled model for motors considering anisotropic magnetization and magnetostrictive properties is proposed and stress distribution of motor cores is calculated. Finally, the frequency spectrum of the stress is analyzed to provide the theoretical basis for further research of inverter-fed induction motor vibration and noise reduction. [ABSTRACT FROM AUTHOR]