Segmented stator switched reluctance motor drive for light electric vehicle

The world market of electric light vehicles will significantly increase in the coming years. What will require the development of better high-performance drives with lowcost, and, if possible, free of permanent magnets. A segmented stator switched reluctance motor is presented to fulfill this objective because it has advantages over the conventional switched reluctance machines, such as segmented stator construction, stator shorter flux paths without flux reversal, and as a consequence, fewer iron losses. Simulations will demonstrate that the proposed segmented stator switched reluctance motor drive is suitable as a powertrain for light electric vehicles.This work was supported by the project TED 2021129912B-I00.Peer ReviewedPostprint (published version

Modular switched reluctance machines to be used in automotive applications

In the last decades industry, including also that of electrical machines and drives, was pushed near to its limits by the high market demands and fierce competition. As a response to the demanding challenges, improvements were made both in the design and manufacturing of electrical machines and drives. One of the introduced advanced technological solutions was the modular construction. This approach enables on a hand easier and higher productivity manufacturing, and on the other hand fast repairing in exploitation. Switched reluctance machines (SRMs) are very well fitted for modular construction, since the magnetic insulation of the phases is a basic design requirement. The paper is a survey of the main achievements in the field of modular electrical machines, (especially SRMs), setting the focus on the machines designed to be used in automotive applications

A novel modular stator hybrid-excited doubly salient synchronous machine with stator slot permanent magnets

This paper presents a novel modular stator hybrid-excited synchronous machine with stator slot permanent magnets (PMs). By regulating the field current, the magnetic field, and consequently the back electromotive force, as well as the average torque can be controlled. The existence of stator slot PMs alleviates the magnetic saturation and improves the flux regulation ratio. The frozen permeability method is employed to investigate the torque contributions by different magnetic sources. Possible stator and rotor pole combinations are illustrated, and the corresponding electromagnetic performances are evaluated with the finite-element method. It is revealed that 12-stator pole machines with 11- and 13-rotor poles exhibit superior average torque and lower torque ripple due to even-order harmonics elimination. Finally, a prototype with modular stator segments is manufactured to validate the analyses and simulations

Finite element based overall optimization of switched reluctance motor using multi-objective genetic algorithm (NSGA-II)

The design of switched reluctance motor (SRM) is considered a complex problem to be solved using conventional design techniques. This is due to the large number of design parameters that should be considered during the design process. Therefore, optimization techniques are necessary to obtain an optimal design of SRM. This paper presents an optimal design methodology for SRM using the non-dominated sorting genetic algorithm (NSGA-II) optimization technique. Several dimensions of SRM are considered in the proposed design procedure including stator diameter, bore diameter, axial length, pole arcs and pole lengths, back iron length, shaft diameter as well as the air gap length. The multi-objective design scheme includes three objective functions to be achieved, that is, maximum average torque, maximum efficiency and minimum iron weight of the machine. Meanwhile, finite element analysis (FEA) is used during the optimization process to calculate the values of the objective functions. In this paper, two designs for SRMs with 8/6 and 6/4 configurations are presented. Simulation results show that the obtained SRM design parameters allow better average torque and efficiency with lower iron weight. Eventually, the integration of NSGA-II and FEA provides an effective approach to obtain the optimal design of SRM

Performance comparison of doubly salient reluctance machine topologies supplied by sinewave currents

This paper comprehensively investigates the electromagnetic performance of 3-phase, 12-slot, and 8-pole switched reluctance machines (SRMs) with different winding configurations, i.e. double/single layer, short pitched (concentrated) and fully pitched (distributed). These SRMs are supplied by sinewave currents so that a conventional 3-phase converter can be employed, leading to behavior which is akin to that of synchronous reluctance type machines. Comparisons in terms of static and dynamic performances such as d- and q-axis inductances, on-load torque, torque-speed curve, efficiency map, etc. have been carried out using two-dimensional finite element method (2-D FEM). It is demonstrated for the given size of machine considered, that for same copper loss and without heavy magnetic saturation, both single and double layer mutually coupled SRMs can produce higher on-load torque compared to conventional SRMs. Additionally, double layer mutually coupled SRM achieved the highest efficiency compared to other counterparts. When it comes to single layer SRMs, they are more suitable for middle speed applications and capable of producing higher average torque while lower torque ripple than their double layer counterparts at low phase current. Two prototype SRMs, both single layer and double layer, are built to validate the predictions

Study on segmented-rotor switched reluctance motors with different rotor pole numbers for bsg system of hybrid electric vehicles

© 1967-2012 IEEE. This paper investigates the design principles and performance optimization for segmented-rotor switched reluctance motors (SRSRMs) with different rotor pole numbers for belt-driven starter generators of hybrid electric vehicles. For the design principles, several constraints are derived for the numbers of stator and rotor poles, the dimensions, and the number of winding turns. Two SRSRMs with 16/10 and 16/14 stator/rotor poles are presented according to these principles. For the performance optimization, the two motors are optimized individually for maximizing the torque. To evaluate the effect of different segmented-rotor numbers, the overall performances of the two SRSRMs are investigated and compared. It is found that the 16/14 SRSRM has higher flux linkage and static torque. The 16/14 SRSRM exhibits higher torque and lower torque ripple at low speed operation, whereas at high speed, the 16/10 SRSRM performs better in terms of torque and power densities. Compared with the 16/14 SRSRM, the 16/10 SRSRM has higher final steady speed under the same startup condition. The 16/10 SRSRM can achieve higher steady speed under starter mode and provide higher generated power under braking mode. Moreover, the 16/10 SRSRM exhibits higher efficiency in the most feasible speed range, especially in high speed range, and it has wider high-efficiency area. Finally, a 16/10 SRSRM is prototyped and tested to validate the simulation results

Comparative evaluation for an improved direct instantaneous torque control strategy of switched reluctance motor drives for electric vehicles

Due to the expected increase in the electric vehicles (EVs) sales and hence the increase of the price of rare-earth permanent magnets, the switched reluctance motors (SRMs) are gaining increasing research interest currently and in the future. The SRMs offer numerous advantages regarding their structure and converter topologies. However, they suffer from the high torque ripple and complex control algorithms. This paper presents an improved direct instantaneous torque control (DITC) strategy of SRMs for EVs. The improved DITC can fulfill the vehicle requirements. It involves a simple online torque estimator and a torque error compensator. The turn-on angle is defined analytically to achieve wide speed operation and maximum torque per ampere (MTPA) production. Moreover, the turn-off angles are optimized for minimum torque ripples and the highest efficiency. In addition, this paper provides a detailed comparison between the proposed DITC and the most applicable torque control techniques of SRMs for EVs, including indirect instantaneous torque control (IITC), using torque sharing function (TSF) strategy and average torque control (ATC). The results show the superior performance of the proposed DITC because it has the lowest torque ripples, the highest torque tor current ratio, and the best efficiency over the low and medium speed ranges. Moreover, the comparison shows the advantages of each control technique over the range of speed control. It provides a very clear overview to develop a universal control technique of SRM for EVs by merging two or more control techniques

SRM drives for electric traction

"GAECE" -- PortadaDescripció del recurs: 11 maig 2020GAECE (Grup d’accionaments elèctrics amb commutació electrònica). The group of electronically commutated electrical drives is a research team of Universitat Politècnica de Catalunya (UPC BARCELONATECH), which conducts investigation in four areas: electrical drives, power electronics, mechanics and energy and sustainability. Regarding electrical drives, research focuses on the development of new reluctance, permanent magnet and hybrid electrical drives. The main goal of those electrical drives is the integration of the power converter/controller and the mechanical transmission, being specially intended for the traction of light electric vehicles. That research is carried out by using the analysis of finite elements, taking into account eco-design criteria, considering new materials and new control strategies.First editio

Reduktion der Drehmomentwelligkeit und sensorloser Betrieb einer geschalteten Reluktanzmaschine

Bei geschalteten Reluktanzmotoren ist besonders die Welligkeit des Drehmomentverlaufs problematisch. Mit einem Simulationsprogramm werden zunächst unterschiedliche Statorstrukturen untersucht mit dem Ziel, diese Welligkeit zu reduzieren. Erreicht wird das durch eine Motorgeometrie, bestehend im Wesentlichen aus einem Versatzkonzept, bei dem die bestromten Statorelemente auf der Umfangslinie in bestimmtem Abstand zueinander versetzt angeordnet sind. Diese Motorgeometrie ist darüber hinaus einfach zu fertigen. Der Bau eines aus diesen Ergebnissen resultierenden Prototyps und eines Umrichters zum Ansteuern des Motors wird erläutert sowie ein Rechenalgorithmus zur Beschreibung der Geometriegestaltung erstellt. Die Umsetzung beider Arbeitsschwerpunkte schließt die Themengebiete „Reduktion der Momentenwelligkeit, durch das geometrische Design eines SRM“ und „Sensorlose Positionsbestimmung eines SRM“ ein. Beide Ziele können mit der vorgestellten Hardware erreicht werden. Zur Positionsbestimmung der Rotorlage wird die Stromform der aktiven Phase analysiert und in Abgrenzung zu bekannten Verfahren die Stromabfallzeit während des Freilaufs verwendet. Die Ansteuerung des Umrichters enthält sowohl die Stromregelung der Motorwicklung als auch die Software zur Lageerkennung ohne zusätzliche Hardwarebausteine. Das vorgestellte Verfahren wird mit einem Prototyp einschließlich mitentwickeltem Umrichter auf einem Prüfstand untersucht. Der Motor wird auch unter Last gefahren, um das Versatzkonzept aus der Simulation heraus zu verifizieren und es dabei zu bestätigen. Die Messauswertung im sensorlosen Betrieb im Vergleich zum Geber bestätigt für den Motor mit und ohne versetzte Statorsegmente, dass beide oben genannten Ziele erfüllt werden können