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

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

Pembangunan portal pendidikan teknik dan vokasional: satu kajian awal di kalangan Pelajar Sarjana PTV Jabatan Pendidikan Teknik dan Vokasional Fakulti Teknologi Kejuruteraan

Tujuan kajian ini adalah untuk mengkaji sejauh manakah keperJuan pelajar terhadap portal Pendidikan Teknik dan Vokasional (PTV). Sebuah portal PTV dibangunkan dalam kajian berasaskan produk ini. Sampel bagi kajian ini terdiri daripada pelajar sarjana pendidikan teknik dan vokasional, semester 3. Dapatan kajian ini dianalisis dengan menggunakan perisian SPSS versi 10. Pada peringkat awal projek ini, keperluan pelajar terhadap portal PTV dikenal pasti. Selepas itu, ciri-ciri yang perlu dibangunkan dalam portal PTV dikenal pasti dengan menggunakan kaedah borang soal selidik. Satu portal PTV dibangunkan berdasarkan dapatan kajian tersebut. Pada peringkat akhir projek ini, penilaian dilakukan ke atas portal PTV yang telah dibangunkan. Tujuan penilaian ini adalah untuk mengenal pasti sejauh manakah portal PTV ini memenuhi keperluan pelajar. Daripada dapatan kajian didapati portal PTV amat diperlukan oleh pelajar. Selain daripada itu, daripada dapatan kajian, portal PTV yang telah dibangunkan ini beryaya memenuhi keperluan pelajar. Cadangan untuk memperbaiki portal PTV yang telah dibangunkan ini diberi oleh responden. Kajian lanjutan patut dilakukan ke atas portal PTV yang telah dibangunkan bagi memperbaiki serta memumikan konsep reka bentuk dan pengurusan maklumat

Segmental rotor switched reluctance drives

One of the well-known drawbacks of switched reluctance machines is the relatively high output torque ripple. Techniques aiming to reduce machine torque ripple either compromise the machine performance or the simplicity of the inverter and the controller. The work presented in this thesis shows that low torque ripple over a wide speed range can be achieved without severe penalties in terms of the machine performance and the size, cost and complexity of the power electronics and the controller. This is achieved by designing a 6-phase machine and driving it from a three-phase full bridge circuit. Switched reluctance motors with segmented rotors are a relatively recent advancement in the electromagnetic design of doubly-salient reluctance motors, having only been introduced in 2002. By replacing the conventional toothed rotor with individual segments, it has been proven that higher torque density than conventional switched reluctance machines could be achieved. Early work by Mecrow and El-Kharashi has demonstrated the operation of prototype machines with short-pitched and fully-pitched windings. The machine design work presented here builds on this early work by examining aspects of the machine design and its operation. Two six-phase machines – one with a segmented rotor and the other with a toothed rotor - have been designed. Performance comparisons have been made between the two six-phase machines and a three phase segmented rotor machine that was previously designed at Newcastle University. Additionally, a three phase single tooth winding and a two phase segmented rotor switched reluctance machine have been studied in simulation and experimentally. Detailed comparison of inverter ratings and machine efficiencies are made under equal conditions for a 2-phase machine driven from h-bridge and asymmetric half-bridge inverters. This is achieved with results from a test rig and the use of accurate dynamic simulation. Simulation models for 3-phase and 6-phase machines have also been generated. Detailed comparison of inverter ratings and machine efficiencies are made under equal conditions for the 3-phase and 6-phase drives in the dynamic simulation. Comparisons between simulated and measured results are shown to be very good for all of the drives.EThOS - Electronic Theses Online ServiceGBUnited Kingdo

Segmental rotor switched reluctance machines for use in automotive traction

PhD ThesisThis thesis explores the development of the Segmental Rotor Switched Reluctance Machine (SRM) to provide electric vehicle traction. This electrical machine, which has a topology distinct from the conventional SRM and has been previously shown to offer enhanced torque density, is selected based on its potential to offer a low cost, sustainable alternative to today’s state-of-the-art electric vehicle traction motors. With the launch, as long ago as 1997, of the Toyota Prius Hybrid Electric Vehicle and of the more recent Nissan Leaf Electric Vehicle in 2010, volume produced vehicle traction drives are an established reality. However hurdles remain in order to reduce the cost of electric and hybrid electric vehicles so that they become cost-competitive with more conventional vehicles. From an electrical machine perspective, one clear cost driver stands out; the rare-earth metals which form the key ingredient in today’s class leading electrical machines. These materials are both expensive (>100USD/kg) and, as was seen in 2011 / 2012, subject to significant price volatility. Equally the mining and refinement of rare-earth materials, such as Neodymium, Dysprosium and Samarium, has been shown to have a much higher environmental footprint than that of the other materials typically used in electrical machines. Beyond the elimination of rare-earths, the thesis looks to further improve the sustainability and cost of the Segmental Rotor SRM. Copper conductors, expensive and difficult to recycle at an electrical machine’s end-of-life, are replaced by more easily recycled aluminium. Aluminium windings are compressed, prior to assembly with the electrical machine, in order to achieve very high fill factors to overcome their relatively low electrical conductivity. Methods are also sought to reduce overall material waste and simplify assembly processes; these include computer based optimisation of the motor structure along with the use of modular manufacturing techniques. With the Nissan Leaf’s Neodymium Iron Boron based Interior Permanent Magnet machine selected as a comparator, an 80kW Segmental Rotor SRM is constructed and tested. The design is shown to have promise and a number of industrially funded follow-on projects are now underway in order to develop the technology further for use in a volume electric vehicle application

Flux switching machines using segmental rotors

Flux switching machines (FSM) employing a segmental rotor have field and armature systems on the stator and a presentation of an unexcited rotor with isolated segments. The single-tooth winding arrangement on the stator provides a potential for material and energy savings. The principle for producing bipolar flux in the armature stator teeth relies on the natural switching of the armature tooth flux, accomplished by the moving segments of the rotor. Three phase configurations have been studied, from conception and design to construction and testing, with field excitation provided by either a field winding or permanent magnets (PM). Flux switching machines have shown characteristics that are peculiar when employing a segmental rotor, significantly affecting the symmetry of the induced armature EMF waveform and parity of magnitudes of the positive and negative torques. For three phase operation, six topologies are feasible when employing a 12-tooth stator and two other topologies may be produced on a 24-tooth stator. An optimum topology on the 12/8-configuration and another proof-of-principle topology on the 12/5-configuration, using field-windings and permanent-magnets, have been designed and constructed, while applying modern practices and considerations for manufacture. The characteristics of FSMs employing a segmental rotor, initially predicted by finiteelement (FE) modelling, have been verified by measurements. The FSM employing a field-winding is found to have a specific torque output which is similar to the conventional switched reluctance motor and still substantially higher than that of the synchronous reluctance motor. Although the PM adaptation of the FSM produces specific torque output which is nearly twice that of the wound-field FSM and about 64% that of an equivalent permanent-magnet synchronous motor (PMSM) with surface or insert magnets, accounting for the usage of the magnets reflects its specific torque output to be about 1.48 times higher than the PMSM. Although the FSM is operated as an AC machine with sinusoidal three-phase currents, its dq-equivalent representation shows significant differences from that of the conventional AC machine. In the prediction of the performance, it is found, in both the wound-field and PM configurations, that the dq model is more dependable if the coupling dq inductance is taken into account.EThOS - Electronic Theses Online ServiceCommonwealth Scholarship Commission of UKGBUnited Kingdo

Design of segmental rotor and non-overlap windings in single-phase fefsm for low torque high speed applications

In this research, a new structure of single-phase field excitation flux switching motor (FEFSM) using segmental rotor structure and non-overlap windings arrangement is proposed in order to overcome the drawbacks of low torque and small power performances due to their longer flux path in the single-phase FEFSM using salient rotor structure and overlap windings arrangement. The objectives of this study are to design, analyse and examine performance of the proposed motor, to optimize the proposed motor for optimal performances, and to develop the proposed motor prototype for experimental performance validation. The design and analyses thru 2Dfinite element analysis (FEA) is conducted using JMAG Designer version 15, while deterministic optimization method is applied in design optimization process. To validate the 2D-FEA results, the motor prototype is developed and tested experimentally. Based on various rotor poles analysis, a combination of 12 pole 6 pole (12S-6P) has been selected as the best design due to their highest torque and power capability of 0.91 Nm and 277.4 W, respectively. Besides, the unbalance armature magnetic flux of the proposed FEFSM using segmental rotor has been resolved by using segmental rotor span refinement. The balanced armature magnetic flux amplitude ratio obtained is 1.002, almost 41.2% reduction from the initial design. In addition, the optimized motor has increased maximum torque and power by 80.25% to 1.65 Nm, and 43.6% to 398.6W, respectively. Moreover, copper loss of the optimized design has decreased by 9.7%%, hence increasing the motor efficiency of 25.3%. Finally, the measured results obtained from the prototype machine has reasonable agreement with FEA results, proving their prospect to be applied for industrial and home appliances

Design Optimization and Comparison of Direct-Drive Outer-Rotor SRMs Based on Fast Current Profile Estimation and Transient FEA

Outer-rotor switched reluctance machines (SRMs) have drawn much attention as promising candidates for in-wheel direct-drive motors of future electric vehicles. This article presents a systematic performance comparison of three outer-rotor SRM topologies for in-wheel traction applications in terms of the specific torque, electromagnetic efficiency, torque ripple, radial force, and mechanical aspects. A generalized design optimization framework for SRMs is proposed to enable the fast evaluation of large numbers of designs generated from the differential evolution by incorporating an analytical current profile estimation into the transient finite element analysis. The relationship between the saliency ratio and converter volt-ampere rating is also discussed. The calculations are then benchmarked with the experimental results from an existing prototype. The effectiveness of the performance prediction method and the proposed optimization approach is validated

Rotary Switched Reluctance Actuator: A Review On Design Optimization And Its Control Methods

A switched reluctance actuator (SRA) is a type of electromagnetic stepper actuator that is gaining popularity for its simple and rugged construction, ability of extremely high-speed operation and hazard-free operation. SRA gained supremacy over permanent magnet actuators due to the fact that its building material are relatively low cost compared to the expensive and rare permanent magnets. SRA is already making its debut in automotive, medical and high precision applications. However, many parties are still oblivious to this new age actuator. This paper reviews the latest literature in terms of journal articles and conference proceedings regarding the different design parameters and control method of SRA. The impact of the parameters on the performance of SRA are discussed in details to provide valuable insight. This paper also discussed the advantages of various novel SRA structure designs that prove to be a huge contribution to the future technology. It is found that several design parameters such as the air gap when kept minimum, increases torque value; while increasing number of phases in SRA minimizes torque ripples. Increased stator and rotor arc angles will increase torque, not to mention a larger excitation current can also achieve the same effect. Researches are often done through Finite Element Method (FEM) analysis to verify the optimized design parameters before fabrication, whilst experimental procedures are executed to verify the simulation results. To ensure smooth phase switching and improved torque output, intelligent controllers are employed in speed control and direct torque control (DTC) methods of SRA