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This paper mainly takes a 6/4 switched reluctance motor (SRM) as an example to analyze the temperature of the motor. In order to establish the equivalent thermal circuit model (ETCM) conveniently, the mechanical structure of the motor is simplified to a certain extent, and the characteristic nodes are divided. Then the heat transfer process in the rotor region, the stator region and the whole motor during the operation of the motor is analyzed, and the ETCM of those regions are established respectively. This method of establishing ETCM is also applicable to superconducting motors. Based on the basic principles of heat transfer, the calculation method of thermal resistance in each ETCM is given in this paper. Then, the three-dimensional (3-D) finite element (FE) temperature field model of the motor is built and compared with the ETCM. Finally, the accuracy of the ETCM is verified by experiments. [ABSTRACT FROM AUTHOR]

Compared with traditional linear motors, such as Linear Permanent Magnet Motors (LPMs) and Linear Induction Motors (LIMs), Linear Flux-Switching Permanent Magnet (LFSPM) motors have the merits of high efficiency, power density, with simple and robotic secondary structure. Despite these advantages, the flux-weakening ability of LFSPM motor is limited and thus the speed range of it is not ideal. As a promising choice, it is feasible to replace the PMs of LFSPM motors with coils made with High Temperature Superconducting (HTS) tapes. By using HTS material, High Temperature Superconducting Linear Flux-Switching Motors (HTS-LFSMs) have good flux-weakening ability while inheriting the edges of LFSM motors. Since the existence of HTS coils, the cooling system has a minimum size and has to take up certain room of the motor. When it comes to applications where the volume of motor is strictly restrained, there may not be enough room for a basic pattern of typical pole pitch combinations for HTS-LFSM, such as 12-7 or 12-9, leading to large thrust ripple. To solve this problem, a method of reducing thrust force using asymmetry mover structure is proposed based on a 9-5 pole pitch ratio. The mechanism and working principle are analyzed and the validation is verified with the help of Finite Element Method (FEM). [ABSTRACT FROM AUTHOR]

Both Linear Switched Reluctance Motor (LSRM) and Linear Flux-Switching Motor (LFSM) have the merits of none-adhesive thrust force and simple and robust secondary structures. Therefore, LSRM and LFSM are quite suitable for applications such as vertical lifting, wave power generation and urban railway transit. To further improve the power density of them, the field windings of LFSM and DC windings of LSRM can be replaced with High Temperature Superconducting (HTS) coils, and thus forming High Temperature Superconducting Linear Flux-Switching Motor (HTS-LFSM) and High Temperature Superconducting Linear Switched Reluctance Motor (HTS-LSRM). Despite their similar structure, they have different working principles and electromagnetic performances. To reveal their merits and drawbacks for urban railway transit system, a comparative investigation is conducted in this paper using Finite Element Method (FEM). [ABSTRACT FROM AUTHOR]

In this paper, an outer rotor interior permanent magnet synchronous machine (IPMSM) with hybrid permanent magnet (PM) material is proposed. The key is to adopt the outer rotor structure with two-layer crescent barriers and hybrid PM material to maximize the output torque and reduce the usage of high-cost rare-earth PM. The ferrite PMs are filled in the middle of the crescent barriers with thicker thickness, while the rare-earth PMs are filled into the bilateral of the crescent barriers with thinner thickness. To verify the effectiveness of the proposed rotor structure, optimizations are first carried out among the conventional rotor structures with single kind of PM material and the proposed rotor structure with hybrid PMs. Then, detailed comparisons have been investigated. Results indicate that the proposed machine has higher torque density than the machine with only ferrite PM and can reduce almost half the usage of rare-earth PM in comparison to the machine with only rare-earth PM. Moreover, the proposed rotor structure is further optimized considering productivity. [ABSTRACT FROM AUTHOR]

This paper presents a new asymmetrical rotor hybrid permanent-magnet (AR-HPM) motor with good torque performances. Different from the traditional symmetrical rotor structure, the asymmetrical rotor structure is employed to improve the torque production. This makes the reluctance torque and the magnetic torque reach the maximum at the same current phase angle. Based on the concepts, the motor is investigated by the finite-element method (FEM). The frozen permeability method (FPM) is applied to divide the torque into the reluctance torque and the magnetic torque. The electromagnetic characteristics and torque performances of the motor are compared with a conventional motor. The results show that the proposed design is efficacious in boosting output torque at the same operating conditions. Moreover, the results also demonstrate that the topology of the proposed AR-HPM motor features the advantage of avoiding the risk of demagnetization. [ABSTRACT FROM AUTHOR]

Permanent magnet (PM) motors adopt interior V-type PMs and fractional-slot concentrated winding for improving the torque density and efficiency. However, the no-load magnetic coefficient will be increased, which would reduce the utilization rate of the PM. The structure parameters of the rotor should be designed reasonably, especially the bridge. This paper calculates the no-load leakage coefficient by establishing the analytical model of the no-load magnetic coefficient. It shows that, the bridge size has an important effect on the no-load magnetic coefficient. The analysis results are verified by the two-dimensional finite element analysis and tests. [ABSTRACT FROM AUTHOR]

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]

Abearingless synchronous reluctance motor (BSRM) is a new type of bearinglessmotors with numerous advantages. The conventional BSRM with a salient-pole rotor is easy to manufacture at the cost of low output torque and high torque ripple. In this paper, a new rotor structure with multilayer flux barrier of the BSRM is proposed to improve performances of torque and levitation force. The key is to optimize flux-barrier layer number, flux-barrier thickness, and magnetic guide thickness. This new rotor structure is comparedwith the conventional one, confirming the validity of the proposed design. The experimental results show that the proposed BSRM can achieve stable operation with satisfactory levitation performance. [ABSTRACT FROM AUTHOR]

In order to overcome common drawbacks of the low torque density and power factor for conventional bearingless synchronous reluctance motors (BSynRMs), a novel BSynRM rotor structure with ferrite magnets is designed in this paper. First, the basic structure and operation principle of the BSynRM are introduced, and the mathematical models of torque and suspension forces are deduced. Second, based on the finite element analysis method, the parameters of flux barriers layer, rotor rib width, and permanent magnets are optimized to increase the salient pole ratio and the difference between d and q axes inductance. Third, the performance of torque, suspension forces, and power factor for the optimized motor is compared with that of the traditional BSynRM. The research results show that the torque density and power factor increase about 54.4% and 56.3% respectively at optimal angle, whereas the average suspension force decreases about 15.7% owing to magnetic saturation. The optimized motor is validated to have good suspension and speed regulation performance. [ABSTRACT FROM AUTHOR]

This paper proposes a new hybrid permanentmagnet (PM)-assisted synchronous reluctance motor, where two types of PM materials of rare-earth PMs and ferrite PMs are employed in its rotor. To reduce the usage of rare-earth materials, a hierarchical design method is adopted in its rotor design, in which the design is divided into two levels: saliency ratio design level and PM usage design level. In saliency ratio design level, proper flux barrier dimensions are confirmed based on the principle of reluctance torque maximization. In PM usage design level, the optimal magnet ratio is first determined according to the relationship of main flux and leakage flux. Then, a tradeoff design is conducted to seek the superior combination of low torque ripple, high efficiency, and high power factor. Finally, for the purpose of validation, the electromagnetic performances of the new designed motor are investigated, including torque characteristics and antidemagnetization capabilities of ferrite. [ABSTRACT FROM AUTHOR]

This paper proposes a high force density tubular permanent-magnet (PM) motor, termed as tubular stator-PM venier motor, for artificial hearts. The novelty of the proposed motor is to artfully integrate two different magnetization directions of PMs and ferromagnetic poles together. The proposed motor incorporates the merits of vernier PM motors and stator-PM motors, offering high back electromotive force, improved force density, minimized cogging force, and reduced PM volume. The influence of the magnet pole ratio on the performance is investigated. The proposed motor is designed and compared with an existing vernier PM motor by using the time-stepping finite-element method, verifying the validation and the advantageous performance of the proposed motor. [ABSTRACT FROM PUBLISHER]

In this paper, a novel high-temperature superconductor (HTS) permanent magnet (PM) vernier motor is proposed for direct-drive propulsion, which can directly offer the low-speed high-torque capability and the high-speed rotating field design to eliminate the gearing mechanism and maximize the power density, respectively. The key is to newly introduce HTS bulks to flux-modulation poles that can effectively modulate between the high-speed rotating field of armature windings and the low-speed rotating field of the PM outer rotor. Also, the use of HTS bulks can greatly reduce the flux leakage and hence improve the torque density. Based on using the finite element method, the motor performances are analysed. Hence, the validity of the proposed motor is verified. [ABSTRACT FROM AUTHOR]

Considering nonlinear magnetization characteristic of switched reluctance motor (SRM), this paper describes a nonlinear model of SRM based on an improved least square support vector machine regression (LSSVR) algorithm optimized by grid-diamond searching (GDS) method. The experimental results show that the GDS method can choose proper parameters of LSSVR while providing better simulation result. Modeling with the optimization parameter, the forecasted data of the model are compared with the experimental data on a four-phase, 8/6 SRM. It is shown that XS-LSSVR optimized by GDS is effectiveness method and performs better forecast accuracy and successful modeling of SRM. [ABSTRACT FROM AUTHOR]

At present, based on the piecewise linear inductance model, the main method for analytic calculation of phase current on switched reluctance generators is flux-linkage divided by inductance, and there is no analysis and deduction in detail on base of the obtained expressions of phase current. Expressions of phase current are solved by the separation variable method, and then the characteristics of current curve and the energy conversion relations are analysed in the paper. Also expressions of phase current are applied to the decision condition of current tendency and the analysis on magnetic field energy in the freewheeling mode. And a method to optimize the firing angle is proposed to get the most average electromagnetic torque. The results of simulation validate the theory in the paper and show that the theory is also applicable to the non-linear inductance model. [ABSTRACT FROM AUTHOR]

A 3-phase, 100 hp, 4 pole, 1800 rpm superconducting synchronous motor built and tested in Korea Electrotechnology Research Institute(KERI). This machine consists of HTS rotor and air-core stator. The HIS field windings are composed of the double-pancake coils wound with AMSC's stainless steel-reinforced Bi-2223 tape conductor. These were assembled on the support structure and fixed by a bandage of glass-fiber composite. The cooling system is based on the heat transfer mechanism of the thermosyphon by using GM cryocooler as cooling source. The cold head is in contact with the condenser of a Ne-filled thermosyphon. The rotor assembly was tested independently at the stationary state and combined with stator. The open circuit, no-load, and short circuit characteristic were obtained. Also, load tests in motor mode driven by inverter and generator mode connected to resister load bank were conducted. This paper will present design, construction, and experimental test results of the 100 hp HTS machine. [ABSTRACT FROM AUTHOR]

Analyzes the mechanical vibration of switched reluctance motor. Magnetic charge force density; Natural frequencies; Deformation of the stator; Radial and transverse vibration amplitudes.

Presents corrections to financial data posted for this article. [ABSTRACT FROM AUTHOR]

Presents theoretical and experimental results for high temperature superconducting (HTS) hysteresis and reluctance motors. Types of HTS electric machines considered; Comparison of specific output power parameters of HTS hysteresis and reluctance motors with conventional hysteresis and asynchronous motors.

Reports on the construction of superconducting reluctance motors with YBCO bulk material with testing up to more than 10 kilowatts. Operation in liquid nitrogen at 77 degrees Kelvin at different frequencies and loads; Small size and low weight of such motors as important advantages for special applications.