Outside-spin brushless D.C. motors are an alternative to conventional D.C. brush permanent magnet motors, especially in applications that require low power and costs and in which high inertia effects are advantageous.This paper presents a procedure for computing power losses in these kinds of machines.Expressions are derived for predicting copper losses, power interrupter losses, stator iron losses in the tooth and in the yoke, mechanical losses, friction and windage.Stray load losses are also considered and evaluated from previous measurements in outside-spin brushless D.C. motors.The results obtained from the approach proposed are compared to those measured on existing motors, showing a good agreement.

This paper is about hybrid reluctance machines, in which the stator or fixed part has a combination of U-shaped electromagnets with permanents magnets placed between their arms while the moving part is simply a structure with salient poles.They can be designed to build different types of rotary or linear electric motors and generators with outstanding performances.In this paper, first, the principle of operation of these machines is explained.Then different types of hybrid reluctance machines using this particular structural configuration are described showing their potential based on simulations and experimental results.

In this paper, a novel in-wheel double rotor axial flux switched reluctance motor for electric traction is presented. The proposed double rotor axial-flux switched reluctance motor has a particular disposition of the stator and rotor poles that provides short flux path without flux reversal. The ferromagnetic pieces of the stator and the rotor are built using soft magnetic composites. Electromagnetic analysis is performed using three dimensional finite element analyses, 3D FEA. Matlab-Simulink simulation coupled with the results of finite element analysis proves that the proposed motor drive is suitable for the propulsion of a given E-scooter.

A current-controlled switched reluctance motor drive for variable speed applications with efficiency optimization is presented.Firing angles are computed online, the turnon is calculated by means of the rule of Bose, and the turn-off is calculated using the general theory of the optimal turn-off angle proposed by Gribble.In steady state operation, the initial selection of firing angles is fine-tuned by means of an algorithm that minimizes the input power of the drive.An efficiency and electrical energy consumption comparison with a commercial vector-controlled induction motor drive of the same size is also included.Experimental results show that the proposed switched reluctance motor drive is a good choice for applications that require slow varying loads and energy savings.

This paper shows the results obtained from the study on the variables that have the greatest influence on the decision to replace three-phase induction motors, without a defined efficiency class and installed in industrial applications, with IE3 efficiency class induction motors. The work has been carried out on motors with a nominal power of 1.5 kW due to the availability of laboratory tests that have allowed us to accurately quantify the selected study variables. According to IEC 60034-30, between 0.75 kW and 4 kW is the greatest potential for energy savings in electric motors installed within the industrial sector. The tests carried out have made it possible to assess different operating conditions of the motor: direct power supply from the grid, electronic power supply using scalar control, and electronic power supply using direct torque control. The study has focused on three aspects: energy evaluation, assessing the savings potential; economic evaluation, based on indicators such as Payback Period and Net Present Value; environmental assessment, quantifying the impact indicators proposed by the Methodology for Ecodesign of Energy-related Products (MEErP). A sensitivity analysis has been carried out to quantify, through ratios, different operating points from those directly analyzed in the article.

This work shows the results obtained from studying the influence of equivalent circuit resistances on three-phase induction motors. The stator resistance, rotor resistance, and iron losses resistance affect the different motor operating variables (output power, current, speed, power factor, starting ratios, and maximum torque). These influences have been quantified, paying particular attention to the losses affected and their impact on efficiency. The study carried out does not apply optimization techniques. It evaluates the different influences of the equivalent circuit’s different resistances on its operation by evaluating applicable constructive modifications concerning available motors. The work has been limited to three-phase induction motors up to 50 kW and low voltage, with the nominal powers of the selected motors being 0.25 kW, 1.5 kW, 7.5 kW, 22 kW, and 45 kW. The tools used to carry out the study are analyzing the equivalent circuit and the simulation of the electromagnetic structure using a finite-element program. The variations proposed in each resistance for all the motors studied is not purely theoretical, as it is based on applying feasible constructive modifications, appropriately analyzed and simulated. These modifications are the variation of the conductor diameter in the stator coils, the change of the section of the rotor cage, and the selection of different ferromagnetic steel types.

Nowadays, there is a renewed interest in switched reluctance machines and especially in axial-flux switched reluctance machines (AFSRM). This paper presents a comprehensive design procedure for modular AFSRM with an inner stator and two exterior rotors that have a new distribution of the stator and rotor poles, resulting in short magnetic paths with no flux reversal. After a description of the proposed machine, the output torque equation is derived from a simplified non-linear energy conversion loop and guidelines for its design are given. Once the preliminary sizing has been carried out the different modules of the AFSRM, the magnetically active parts made with SMC, are reshaped or refined using 3D printing and 3D electromagnetic finite element analysis until they reach their definitive shape and dimensions. Finally, an AFSRM has been built following the proposed design procedure and has been validated by experimental measurements.

Switched Reluctance Machines (SRM) are emerging as a possible alternative in terms of cost and supply stability to rare earth based electric vehicle traction systems. However, because of the huge amounts of energy stored and transferred back and forth between the DC source and the SRM, large DC-link capacitors must be used as buffers, which increases overall costs and size. This paper proposes a novel modulation technique which forces the exchange of energy between phases while decreasing the energy transfer between the DC bus and the SRM. This means lower DC bus currents (capacitor size and cost reduction) and lower Joule-effect conduction losses (better efficiency). The proposed modulation has been validated experimentally in a test bench and compared with the conventional torque-sharing function.

In a near future when Industry 4.0 is implanted, predictive maintenance will have a much more prominent role than that currently plays in traditional industry. Predictive maintenance is the organized monitoring with periodic or continuous measurement of variables of the state of the equipment to be maintained and its comparison with pre-established patterns for the determination of the instant in which the maintenance intervention should take place. Three-phase induction motor drives are one of the industrial equipment that has been given greater attention regarding predictive maintenance plans. In recent years, switched reluctance motor drives have begun to have some relevance in the industry. In this paper, after a brief review of the switched reluctance motors and their control, an analysis of the different types of faults and a description of the most usual diagnostic techniques in electric drives, a predictive maintenance plan for switched reluctance motor drives is proposed. This predictive maintenance plan considers different control strategies (hysteresis and single pulse), and is based on diagnostic techniques such as analysis of currents and spectral analysis of vibrations. Exhaustive experimental tests have been carried out in order to validate the proposed plan.

This paper investigated the influence of manufacturing and assembly defects and the quality of materials on the performance of an axial-flux switched reluctance machine (AFSRM). An AFSRM drive was designed and built for the in-wheel propulsion of an electric scooter. The motor was tested according to the standard IEC 60349-Part 1, but the obtained results were below the expected result. The causes of the discrepancy between the simulated and experimental results were analyzed. After an exhaustive study, manufacturing and assembly deficiencies and the quality of materials were identified as the main causes of the mentioned discrepancies. Static torque was used to assess the impact of the different causes in these discrepancies. Finally, some recommendations are proposed to improve the construction of this kind of machine.

Revenues from global sales of light electric vehicles are expected to grow from $ 9.3 billion in 2017 to $ 23.9 billion in 2025. In order to boost this growth electric drives with better features and lower costs have to be developed. This paper presents a new in-wheel axial-flux switched reluctance motor with double rotor and a particular disposition of the stator and rotor poles that provides short flux path without flux reversal. The magnetic active parts of the stator and the rotor are built using soft magnetic composites. The motor is fed from batteries trough a on purpose designed electronic power controller. Simulation of the whole drive, using Matlab-Simulink coupled with the results of the three dimensional finite analysis of the motor is carried out. Simulation results prove that the proposed in-wheel axial-flux switched reluctance motor drive is adequate for the propulsion of electric light vehicles.

Nowadays, switched reluctance motor drives are one of the most promising alternatives for the elimination of permanent magnets in the electric traction systems, due to their well-known advantages such as simple and rugged construction, high efficiency, speed torque characteristic well adapted to traction needs and despite their drawbacks high torque ripple and high acoustic noise. Unfortunately, nowadays, the lack of commercial controllers intended for switched reluctance motors slows down its use as power traction unit. This paper tries to overcome this barrier proposing a specific controller, understood as the assembly of electronic power converter and control unit, for electric light vehicles. First, the specifications of the controller will be exposed then a comprehensive description of the architecture of the controller and details about the choice of its components will be given. Finally, experimental results will be shown in order to demonstrate its suitability as a SRM controller for light electric vehicles.

The objective of this paper is to present an original study for optimizing the size of the longitudinal-flux double-sided linear switched reluctance motor (LSRM) under thermal and weight constraints. The performance is evaluated taken into account duty cycle operating conditions and thermal restrictions. The proposed approach couples finite element analysis for magnetic propulsion force computation and lumped-parameter thermal network for thermal transient analysis. The LSRMs design parameters are characterized by the number of phases and by their size denoted by the pole stroke. The operating conditions are the current density, the duty cycle and the admissible temperature rise of the insulation system. The grid search algorithm is used for solving the optimization problem. From the results, with the help of a novel multivariable optimization chart, a set of optimal configurations regarding to miniaturizations and downsizing of LSRMs is provided.

In this paper a novel axial-flux segmented rotor switched reluctance motor (AFSSRM) with a stator sandwiched by two rotors with a particular form of the segments is presented. The machine has magnetic short paths with no flux reversal and the active magnetic parts are made of soft magnetic composites. An in-wheel AFSSRM, specially intended for direct drive of light motorcycles, is designed. Electromagnetic analysis of the AFSSRM is carried out using 3D finite element. Matlab-Simulink simulations of the whole in-wheel AFSSRM drive are used to verify its behavior.

The world market of e-scooter is expected to experiment an increase of 15% in Western Europe between 2015 and 2025. In order to push this growth it is needed to develop new low-cost more efficient and reliable drives with high torque to weight ratio. In this paper a new axial-flux switched reluctance motor is proposed in order to accomplish this goal. The motor is constituted by a stator sandwiched by two rotors in which the ferromagnetic parts are made of soft magnetic composites. It has a new disposition of the stator and the rotor poles and shorter flux paths Simulations have demonstrated that the proposed axial-flux switched reluctance motor drive is able to meet the requirements of an e-scooter.

Nowadays, the power steering is a standard device in commercial vehicles. The electric power steering is becoming an alternative to the traditional hydraulic power steering. Right now, the electric drive commonly used in this application is the DC brush motor drive. Today, different electric drives are seen as a future option but the best candidate seems to be the permanent magnet synchronous motor drive. However due to its constructive simplicity, absence of permanent magnets and fault tolerance the switched reluctance motor drive is an alternative that should not be ignored. In this article a switched reluctance motor drive is presented for a rack-type electric power steering for midsize cars with a rack force 10 kN. The drive consists of a switched reluctance motor of four-phase with 8 stator poles and 6 rotor poles fed through an electronic power converter with Power MOSFETs switches, an incremental encoder and digital torque control to minimize torque ripple and to mitigate disturbances that appear when clearing a fault and the drive works with one or two open phases. The drive has been built and tested in the laboratory and experimental results have confirmed its suitability as a drive for power steering.

espanolEn el XIII CUIEET celebrado en las Palmas de Gran Canaria en septiembre de 2005 los autores, profesores de la EPS de Vilanova i la Geltru (EPSEVG), UPC BARCELONATECH, presentaron una comunicacion titui lada: «Introduccion de las consideraciones energeticas, ambientales y eco- nomicas en la ensenanza de las maquinas electricas». Ahora se propone una nueva comunicacion, que es una puesta al dia de la comunicacion de 2005, en el contexto de los estudios de Grado en la que se hacen propuestas de como implementar la sostenibilidad en la docencia de las maquinas electricas. EnglishIn XIII CUIEET held in Las Palmas de Gran Canaria, in September 2005, the authors, professors of the EPS Vilanova i la Geltru (EPSEVG), UPC BARCELONATECH, presented a paper entitled: «Introduction of eneri gy, environmental ancl economic consideralions in teaching of electrical machines». Now, a new communication, which is an update of the 2005 paper, is presented in the context of graduate studies, in Which proposals are made on how to implement sustainability in the context of teaching electrical machines.

This article presents an exhaustive study about the influence of some design parameters, such as the number of phases, pole stroke, and current density, in the behavior of a linear switched reluctance motor. The linear switched reluctance motor's performance is assessed, taking into account a set of quality indices, which are the energy conversion loop quality factor, propulsion force per unit of primary steel volume, per unit of copper mass, per unit of air-gap surface, and force ripple factor. The study is carried out by means of two-dimensional finite-element analysis. Finally, the results are discussed, and as a consequence, a set of linear switched reluctance motor configurations with optimal performance according to the quality indices is defined.

In this paper is intended to study a three phase induction motor for railway applications. The steady state equivalent circuit is used to include and quantify all motor losses in the power balance. The use of the proposed equivalent circuit, which allows a reliable assessment of the loss distribution and performance of this motor at different operating points, so comes as a particularly interesting tool to evaluate efficiency improvements, either in the motor design or in the materials selection. Currently motor performance evaluation in railway applications is especially interesting, where the energy consumption has a significant economic and environmental impact.