Optimal design of switched reluctance motors

The fundamental theory of the switched reluctance motor is presented with a number of new equations. It is used to show how the practical development of a design calculation should proceed, and this leads to a discussion of physical characteristics required to achieve satisfactory performance and to reduce acoustic noise. The paper makes a few generic observations on the characteristics of successful products that use switched reluctance motors. It is written at a basic engineering level and makes no attempt to apply sophisticated optimization theory

Design and Performance Analysis of Double Stator Axial Flux PM Generator for Rim Driven Marine Current Turbines

This paper deals with the design and performance analysis of double stator axial flux permanent magnet generators for rim-driven marine current turbines (MCT). Indeed for submarine applications, drive train reliability is a key feature to reduce maintenance requirements. Rim-driven direct-drive multi-stator generators can therefore be a very interesting solution to improve this reliability. In this context, the presented work focus on the design of a double-stator axial flux permanent magnets (PM) generator as a rim-driven direct-drive multi-stator generator. The paper details the models, specifications and an optimization procedure that allow to preliminary design these kind of generators for rim-driven marine turbines. Thereafter, validations with finite elements computations and performance analysis considering particular design of rimdriven generators are presented. The obtained results highlight some designs issues of PM generators for rim driven marine turbines. In order to assess the effectiveness of the double stator axial flux PM generator, a comparison with a designed surface mounted radial flux PM generator for rim marine turbines is carried out.. The comparison highlights that the double stator axial flux generator presents a better cooling and a reduced active parts cost and mass than the radial flux PM generator.International audienceThis paper deals with the design and performance analysis of double stator axial flux permanent magnet generators for rim-driven marine current turbines (MCT). Indeed for submarine applications, drive train reliability is a key feature to reduce maintenance requirements. Rim-driven direct-drive multi-stator generators can therefore be a very interesting solution to improve this reliability. In this context, the presented work focus on the design of a double-stator axial flux permanent magnets (PM) generator as a rim-driven direct-drive multi-stator generator. The paper details the models, specifications and an optimization procedure that allow to preliminary design these kind of generators for rim-driven marine turbines. Thereafter, validations with finite elements computations and performance analysis considering particular design of rimdriven generators are presented. The obtained results highlight some designs issues of PM generators for rim driven marine turbines. In order to assess the effectiveness of the double stator axial flux PM generator, a comparison with a designed surface mounted radial flux PM generator for rim marine turbines is carried out.. The comparison highlights that the double stator axial flux generator presents a better cooling and a reduced active parts cost and mass than the radial flux PM generator

High performance and low-cost permanent magnet devices

In this thesis the investigation of the modelling, design and analysis of novel permanent magnet machine for cost sensitive applications is presented. More specifically, a novel technique of arranging Ferrite permanent magnets with low energy density to achieve high airgap flux densities like those encountered in devices equipped with high cost rare-earth permanent magnets, thus, achieving significant cost savings, without substantial change in performance. Consequently, a spoke-type rotor equipped with axially magnetized permanent magnets in addition to the conventional circumferential permanent magnets is proposed, in order to increase the flux focusing and the airgap flux density

An Improved Sideband Current Harmonic Model of Interior PMSM Drive by Considering Magnetic Saturation and Cross-Coupling Effects

The sideband current harmonics, as parasitic characteristics in permanent-magnet synchronous machine (PMSM) drives with space vector pulsewidth modulation technique, will increase the corresponding electromagnetic loss, torque ripple, vibration, and acoustic noises. Therefore, fast yet accurate evaluation of the resultant sideband current harmonic components is of particular importance during the design stage of the drive system. However, the inevitable magnetic saturation and cross-coupling effects in interior PMSM drives would have a significant impact on the current components, while the existing analytical sideband current harmonic model neglects those effects. This paper introduces a significant improvement on the analytical model by taking into account these effects with corresponding nonlinear factors. Experimental results are carried out to underpin the accuracy improvements of the predictions from the proposed model over the existing analytical one. The proposed model can offer a very detailed and insightful revelation of impacts of the magnetic saturation and cross-coupling effects on the corresponding sideband current harmonics

Design of a miniature permanent-magnet generator and energy storage system

The paper describes a methodology for optimizing the design and performance of a miniature permanent-magnet generator and its associated energy storage system. It combines an analytical field model, a lumped reluctance equivalent magnetic circuit, and an equivalent electrical circuit. Its utility is demonstrated by means of a case study on a 15-mW, 6000-r/min generator, and the analysis techniques are validated by measurements on a prototype system

Mathematical Models for the Design of Electrical Machines

This book is a comprehensive set of articles reflecting the latest advances and developments in mathematical modeling and the design of electrical machines for different applications. The main models discussed are based on the: i) Maxwell–Fourier method (i.e., the formal resolution of Maxwell’s equations by using the separation of variables method and the Fourier’s series in 2-D or 3-D with a quasi-Cartesian or polar coordinate system); ii) electrical, thermal and magnetic equivalent circuit; iii) hybrid model. In these different papers, the numerical method and the experimental tests have been used as comparisons or validations

Influence of the amount of permanent-magnet material in fractional-slot permanent-magnet synchronous machines

The efficiency of permanent-magnet (PM) synchronous machines with outer rotor and concentrated windings is investigated as a function of the mass of magnets used, keeping the power, volume, and mechanical air-gap thickness constant. In order to be useful for electric vehicle motors and wind turbine generators, the efficiency is computed in wide speed and torque ranges, including overload. For a given type and amount of magnets, the geometry of the machine and the efficiency map are computed by analytical models and finite-element models, taken into account the iron loss, copper loss, magnet loss, and pulsewidth-modulation loss. The models are validated by experiments. Furthermore, the demagnetization risk and torque ripple are studied as functions of the mass of magnets in the machine. The effect of the mass of magnets is investigated for several soft magnetic materials, for several combinations of number of poles and number of stator slots, and for both rare earth (NdFeB) magnets and ferrite magnets. It is observed that the amount of PM material can vary in a wide range with a minor influence on the efficiency, torque density, and torque ripple and with a limited demagnetization risk

Design and Analysis of New Concept Interior Permanent Magnet Synchronous Motor by 3D Finite Element Analysis

Throughout the years Hybrid Electric Vehicles (HEV) require an electric motor which has high power density and wide constant power operating region as well as low manufacturing cost. For these purposes, a new concept permanent magnet motor is designed and analyzed with the basic theories about Interior Permanent Magnet Synchronous Motor (IPMSM). This new motor has DC excitation coils and flux paths, which can increase the output torque and be controlled for field weakening operating. The analysis has been conducted by three-dimensional Finite Element Analysis. The results show the possibility of the new motor for HEV applications. The new motor has several advantages: low manufacturing cost, low inertia of the rotor, and the direct controllability of air-gap flux