Air-Gap Convection in a Switched Reluctance Machine

Switched reluctance machines (SRMs) have recently become popular in the automotive market as they are a good alternative to the permanent magnet machines commonly employed for an electric powertrain. Lumped parameter thermal networks are usually used for thermal analysis of motors due to their low computational cost and relatively accurate results. A critical aspect to be modelled is the rotor-stator air-gap heat transfer, and this is particularly challenging in an SRM due to the salient pole geometry. This work presents firstly a review of the literature including the most relevant correlations for this geometry, and secondly, numerical CFD simulations of air-gap heat transfer for a typical configuration. A new correlation has been derived: $\mathbf{Nu=0.181\ Ta_m^{0.207}}$Comment: 2015 Tenth International Conference on Ecological Vehicles and Renewable Energies (EVER), 10 figures, 7 page

In-wheel axial-flux SRM drive for light electric vehicles

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

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 topology of high-speed SRM for high-performance traction applications

A novel topology of high-speed Switched Reluctance Machine (SRM) for high-performance traction applications is presented in this article. The target application, a Hybrid Electric Vehicle (HEV) in the sport segment poses very demanding specifications on the power and torque density of the electric traction machine. After evaluating multiple alternatives, the topology proposed is a 2-phase axial flux machine featuring both segmented twin rotors and a segmented stator core. Electromagnetic, thermal and mechanical models of the proposed topology are developed and subsequently integrated in an overall optimisation algorithm in order to find the optimal geometry for the application. Special focus is laid on the thermal management of the machine, due to the tough thermal conditions resulting from the high frequency, high current and highly saturated operation. Some experimental results are also included in order to validate the modelling and simulation results

A review on integrated battery chargers for electric vehicles

Electric vehicles (EVs) contain two main power electronics systems, namely, the traction system and the battery charging system, which are not used simultaneously since traction occurs when the EV is travelling and battery charging when the EV is parked. By taking advantage of this interchangeability, a single set of power converters that can perform the functions of both traction and battery charging can be assembled, classified in the literature as integrated battery chargers (IBCs). Several IBC topologies have been proposed in the literature, and the aim of this paper is to present a literature review of IBCs for EVs. In order to better organize the information presented in this paper, the analyzed topologies are divided into classical IBCs, IBCs for switched reluctance machines (SRMs), IBCs with galvanic isolation, IBCs based on multiple traction converters and IBCs based on multiphase machines. A comparison between all these IBCs is subsequently presented, based on both requirements and possible functionalities.This work has been supported by FCT - Fundação para a Ciência e Tecnologia within the R&D Units Project Scope: UIDB/00319/2020. T.J.C.S. is supported by the FCT scholarships SFRH/BD/134353/2017 and COVID/BD/151993/2021

Design of a high speed 18/12 switched reluctance motor drive with an asymmetrical bridge converter for electric vehicles

The application of permanent magnet free motors have gained a huge attention for pure electric and hybrid electric vehicles. This paper proposed the design of 20-kW switched reluctance motor having 18 stator poles and 12 rotor poles by using finite element analysis machine design software Infolytica magnet and the main focus is to achieve the high speed, torque with adequate performance for electric vehicles. The asymmetric bridge converter has been used and the series of varying the excitation voltage, slot fill factor with respect to the number of turns and stranded area of the conductor has been analysed. Additionally, in order to the electromagnetic force vector, the switching sequence is examined. The simulation results show the great potential of the suggested motor and can provide a good starting torque with high speed and can be suitable to achieve the freedom Car 2020 electric vehicle target

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

Switched reluctance motor controller for light electric 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 vehiclesPostprint (author's final draft

Overview of Sensitivity Analysis Methods Capabilities for Traction AC Machines in Electrified Vehicles

© 2021 The Author(s). This work is licensed under a Creative Commons Attribution 4.0 License. For more information, see https://creativecommons.org/licenses/by/4.0/.A robust design in electrified powertrains substantially helps to enhance the vehicle's overall efficiency. Robustness analyses come with complexity and computational costs at the vehicle level. The use of sensitivity analysis (SA) methods in the design phase has gained popularity in recent years to improve the performance of road vehicles while optimizing the resources, reducing the costs, and shortening the development time. Designers have started to utilize the SA methods to explore: i) how the component and vehicle level design options affect the main outputs i.e. energy efficiency and energy consumption; ii) observing sub-dependent parameters, which might be influenced by the variation of the targeted controllable (i.e. magnet thickness) and uncontrollable (i.e. magnet temperature) variables, in nonlinear dynamic systems; and iii) evaluating the interactions, of both dependent, and sub-dependent controllable/uncontrollable variables, under transient conditions. Hence the aim of this study is to succinctly review recent utilization of SA methods in the design of AC electric machines (EM)s used in vehicle powertrains, to evaluate and discuss the findings presented in recent research papers while summarizing the current state of knowledge. By systematically reviewing the literature on applied SAs in electrified powertrains, we offer a bibliometric analysis of the trends of application-oriented SA studies in the last and next decades. Finally, a numerical-based case study on a third-generation TOYOTA Prius EM will be given, to verify the SA-related findings of this article, alongside future works recommendations.Peer reviewe

In-wheel motor vibration control for distributed-driven electric vehicles:A review

Efficient, safe, and comfortable electric vehicles (EVs) are essential for the creation of a sustainable transport system. Distributed-driven EVs, which often use in-wheel motors (IWMs), have many benefits with respect to size (compactness), controllability, and efficiency. However, the vibration of IWMs is a particularly important factor for both passengers and drivers, and it is therefore crucial for a successful commercialization of distributed-driven EVs. This paper provides a comprehensive literature review and state-of-the-art vibration-source-analysis and -mitigation methods in IWMs. First, selection criteria are given for IWMs, and a multidimensional comparison for several motor types is provided. The IWM vibration sources are then divided into internally-, and externally-induced vibration sources and discussed in detail. Next, vibration reduction methods, which include motor-structure optimization, motor controller, and additional control-components, are reviewed. Emerging research trends and an outlook for future improvement aims are summarized at the end of the paper. This paper can provide useful information for researchers, who are interested in the application and vibration mitigation of IWMs or similar topics