Design of high speed synchronous reluctance machine

This thesis describes the work done during the several stages of the design, analyse, manufacture and test of a high speed synchronous reluctance machine capable of delivering 5 kW at 80 krpm. In order to meet such demanding speed requirement, several multi-disciplinary design exercises have been carried out having different aims. First the influences of the speed-dependent limiting factors on the machine performance have been investigated by analytical methodologies. After the preliminary analytical design, the main challenges related with the structural and electromagnetic FE-based design refinements have been identified. A comparative study has been then presented with the purpose of identify the most effective rotor design approach in terms of performance of the final design and computational effort related for its achievement. Once the design strategy has been chosen, the advantages of considering rotor parametrization of increasing complexity are evaluated via a comparative study showing the results of several structural optimizations. This study indicated the optimal geometry to manufacture. Prior to the machine prototyping, the influence of the rotor manufacturing tolerance as well as the thermal limitations on the machine performance have been deeply analysed. Tests carried out on the prototype have essentially validated the proposed design approach. In addition, an investigative study aimed at identifying and understanding the reasons of the found discrepancy between the measured and expected performance is also reported

WEUSEDTO—Water End USE Dataset and TOols: An open water end use consumption dataset and data analytics tools

Globalization, climate changes, innovative technologies and new human habits have increased atten- tion to water conservation and management. Therefore, behavioural studies became a key element to understand how and when water is used in residential environment. Water End USE Dataset and TOols (WEUSEDTO), an open water end use consumption dataset and data analytics tools, has been released to help researchers, water utilities and companies to test models and algorithms on real water consumption data. The dataset combines with some notebook python able to analyse high-resolution water data (data recorded with 1 sample per second) to provide several tools to manage raw data, compute statistical analysis, learn fixture usage and generate synthetic simulation models. In addition, washbasin flow data were used as a test case to illustrate the main features of WEUSEDTO: providing volume and duration of single events, classifying usages and simulating user’s behaviour

Design optimization of a high-speed synchronous reluctance machine

Synchronous reluctance machines, including the per¬manent magnet assisted variants are competitive motor topologies if the application requires high efficiency and a cost effective solution with a high flux weakening capability. However, increas¬ing operating speeds incur challenging design and development decisions, mainly in order to find design solutions that ensure the machines structural integrity without compromising the overall performance. In this paper, a comprehensive design procedure for high speed synchronous reluctance machines is presented. In order to validate the procedure, a 5 kW, 80000 rpm machine is considered. The proposed strategy consists of a two-step procedure in which the electromagnetic and structural designs have been properly decoupled dividing the design space in two subsets. Each subset mainly affects the electromagnetic or the structural performances. Several structural design optimizations have been then performed with the aim of finding the optimal trade-off between the rotor geometrical complexity (that defines the required computational resources) and the electromagnetic performance. The reported experimental tests of the prototyped machine validate the proposed design strategy which can be used as general guidelines on the structural design of synchronous reluctance machines

Axial eccentric SynRel and SPM Motors analytical models validation using 3D finite element

This paper deals with the uniform and non-uniform axial eccentricity analyses of the surface mounted permanent magnet and synchronous reluctance machines. The analyses are carried out using an analytical model for each considered machine. Being the axial eccentricity a 3D physical phenomenon, the standard sliding approach used in the analytical models has been validated through accurate 3D FE simulations. The results presented in this paper verify the effectiveness of the analytical approaches quantifying the results deviations respect to the computational expensive 3D FE simulations. The results also confirms that synchronous reluctance machines show higher radial forces compared to the surface permanent magnet machines for the same eccentricity level, main geometry and operating condition

High speed drives review: machines, converters and applications

The development of new power electronic device and high performance magnetic materials are the main technological factors that have led both industries and research community to focus their attention on high speed electrical drives. Several papers have already outlined the electrical machine and/or converter topology choice for certain high speed application. This choice depends on the applications under study. This paper aims to identify the most important high speed applications. For each of them, the main design challenges are highlighted and an overview of available market product is presented

Celiac crisis as the life-threatening onset of celiac disease in children. a case report

Celiac disease (CD) is an immune-mediated enteropathy caused by a permanent sensitivity to gluten in genetically susceptible individuals. In rare cases, CD may occur with a severe potential life-threatening manifestation known as a celiac crisis (CC). This may be a consequence of a delayed diagnosis and expose patients to possible fatal complications. We report the case of a 22-month-old child admitted to our hospital for a CC characterized by weight loss, vomiting, and diarrhea associated with a malnutrition state. Early identification of symptoms of CC is essential to provide a prompt diagnosis and management

Rotor Slot Design of Squirrel Cage Induction Motors with Improved Rated Efficiency and Starting Capability

Among the electro-mechanical devices transforming energy from electrical to mechanical, the squirrel cage induction motor can be surely considered a workhorse of the industry due to its robustness, low cost and good performance when directly fed by the a.c. grid. Being the most influencing motor topology in terms of energy consumption, optimizing the efficiency of squirrel cage induction motors could lead to a great impact towards the reduction of the human environmental footprint. The induction motor design aided by finite element analysis presents significant challenges because an accurate performance prediction requires a considerable computational burden. This paper makes use of an innovative fast and accurate performance evaluation method embedded into an automatic design procedure to optimize different rotor slot geometries. After introducing the performance estimation approach, its advantages and limits are discussed comparing its prediction with the experimental tests carried out on an off-the-shelf induction motor. Different rotor cage structures with increasing geometrical complexity are then optimized in terms of starting and rated performance adopting the same design optimization process, the same stator geometry and constituent materials. The analysis of the optimal solutions shows how it is possible to improve the rated efficiency without compromising other performance indexes. The presented results can be used as general design guidelines of squirrel cage induction motors for industrial applications

Acute appendicitis in infants

Acute appendicitis is very uncommon in the first year of life and often its presentation is atypical with high risk of complications. Hereby, we present 4 clinical cases of infants, who were diag- nosed with acute appendicitis in our hospital over the last year. The reported clinical cases high- light the several drawbacks clinicians face when managing infants with symptoms suggestive for acute appendicitis. After specific diagnostic work-up, even if not conclusive, patients were intra- operatively diagnosed with acute appendicitis and underwent appendicectomy. Maintaining a high index of suspicion for acute appendicitis in infants presenting with intra-abdominal sepsis of unclear etiology is, in our opinion, the most crucial factor to avoid complications and longer hospitalization

A Novel Flux Barrier Parametrization for Synchronous Reluctance Machines

This paper presents a novel parametrization for the flux barrier profiles of synchronous reluctance and permanent magnet assisted reluctance machines. In literature there are several methods used to design rotor flux barriers of various types, however the vast majority use only a few parameters to characterize their shape. These approaches are proven to be effective in terms of simplicity and computational burden required to achieve an optimal design. However, simplified parametrizations certainly decrease the degrees of freedom when designing the whole barrier shape. In this paper, an attempt to increase the degrees of freedom, introducing a novel rotor flux barrier parametrization, is presented. The method proposed uses natural splines, defined by the positions of a set of control points, to form the shape of the flux barriers. The spline and state-of-the-art barrier profiles are compared from both electromagnetic and mechanical perspectives. The results of this investigation show that by increasing the degrees of freedom it is possible to obtain better performance characteristics. The proposed parametrization is applied to a 6-pole synchronous reluctance motor and its permanent magnet assisted variant, optimized for a traction application. A prototype has been manufactured and tested to experimentally validate the design methodology