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In order to improve the driving performance of electric vehicles (EV), a permanent magnet synchronous motor with double V-shaped magnet structure (DVMPMSM) and its driving system are studied in this paper. A 150 kW DVMPMSM for EV is designed firstly, and the design parameters of the motor are determined. In order to overcome the drawbacks of the finite element analysis (FEA), especially the issue on calculating time, a dynamic equivalent magnetic network (EMN) model of the DVMPMSM is constructed, by which the air gap flux density, back electromotive force, electromagnetic torque and winding inductance parameters of the motor can be solved. Compared with the FEA, the dynamic EMN model constructed in this paper greatly increases the calculation speed while the calculation accuracy is maintained well. This paper also introduces the stator winding switching method to replace the field-weakening control method. Then, a vector control method of DVMPMSM based on dynamic EMN model and stator winding switching is proposed. The demands brought forward by EV for high torque output under low speed and high upper limit of speed can be well satisfied. Finally, the accuracy of the dynamic EMN model and the effectiveness of the proposed control method is validated through prototype experiments. [ABSTRACT FROM AUTHOR]

This paper presents the design and analysis of electromagnetic characteristics of a five phase permanent magnet synchronous generator for direct drive wind energy conversion system (WECS). In this study, simple and accurate Dynamic Reluctance Network Modeling is used for design and optimization of generator. The anisotropic structure of stator and rotor for the accurate prediction of flux distribution in the air gap and electromagnetic performance is accounted by the dynamic variation of air gap reluctance in an electrical period. This model considers the leakage flux paths for machine design optimization to achieve better performance. In this context, three permanent magnet (PM) materials namely NdFeB, SmCo and ferrite are considered to evaluate the generated voltage. The dimensions of these permanent magnets are varied and performance under normal and saturated core condition is evaluated. A prototype is developed in the machine laboratory of the IIT(BHU) Varanasi (India) and results obtained in accordance with Finite Element Method. [ABSTRACT FROM AUTHOR]

A fast calculation method of magnetic flux density in axial flux permanent magnet (AFPM) machine is presented. This method is based on an original combination of magnetic charges concept, image theory, and relative permeance functions. Using this combined approach, significant 3D effects, which are present in axial flux machines such as curvature and edge effects as well as slotting effects due to stator slots, are considered. The main electromagnetic specifications of the AFPM machine such as cogging torque, Back Electromotive Force (EMF), and local air-gap flux density are calculated accurately in very short times. To validate this approach, an original prototype of double stator ironless rotor AFPM machine with adjustable air-gap is used. Experimental protocol including measurements of global characteristics (EMF, Torque) and measurements of local field density is presented. The obtained results are in good agreement with the experimental measurements which allows validating the proposed computation method. • 3D magnetic field computation method in AFPM machines. • Evaluation of global and local quantities. • Experimental protocol description. • Comparison with measurements and 3D-FEM. [ABSTRACT FROM AUTHOR]

• Comparison of HTS-Bulk and PM in Vernier machine. • Adding PM on the stator with correct direction improves performance of Vernier machine. • HTS-Bulk due to the zero relative permeability and high magnetic reluctance reduces the leakage flux. Today, superconductor materials are widely used in electric machines because of their unique properties. This has been always a question for designers and researchers whether super-conductors can be a good substitute for Permanent Magnet (PM) or not. In this paper, the performance of a dual stator linear vernier machine under identical conditions in the presence of High-Temperature Superconductor Bulk (HTS-Bulk) and PM are analyzed and compared. HTS-Bulk and PM are located between the slot of the stator to illustrate the advantages and disadvantages of the superconductor. The performance of both machines is based on the magnetic gear effect which due to the existence of numerous magnetic pole pairs is able to generate relatively high thrust force at very low speed. The main parameters of both machines such as: air gap flux density, PM flux, back-EMF, self-inductance, mutual-inductance, power factor, detent force and thrust force have been compared to each other at the same geometry by finite element method. [ABSTRACT FROM AUTHOR]

• HTS-Bulk on the stator is used to shield the leakage flux. • Air gap magnetic flux is increased. • Proposed machine is fault-tolerant. In this paper, a high-temperature superconductor-dual stator linear permanent magnet Vernier machine (HTS-DSLPMVM) with Halbach array has been proposed for wave energy conversion. In order to better investigate, this machine has been compared to the prototype double stator linear permanent magnet Vernier machine (DSLPMVM). Both of the machines operate based on magnetic gear effect. At lower speeds they have the ability to produce a high thrust force. DSLPMVM and HTS-DSLPMVM have the same structure. So that, DSLPMVM and HTS-DSLPMVM consist of two stators and one translator with a three-phase concentrated winding. Each phase has been located independently on the translator. Also, permanent magnet (PM) Halbach array with appropriate magnetic direction mounted among the slot of the translator. The innovation of the proposed machine is that HTS-Bulk is located between the slot of the stators to shield the leakage flux. The operation of the two machines has been compared and analysed using the finite element method (FEM). Results show that, HTS-Bulk makes back-EMF, air gap flux density, power factor and thrust force to increase significantly and inductance to decrease, which effectively improves the machine operation. [ABSTRACT FROM AUTHOR]