Fault-Tolerant Control of a Flux-switching Permanent Magnet Synchronous Machine

Je jasné, že nejúspěšnější konstrukce zahrnuje postup vícefázového řízení, ve kterém každá fáze může být považována za samostatný modul. Provoz kterékoliv z jednotek musí mít minimální vliv na ostatní, a to tak, že v případě selhání jedné jednotky ostatní mohou být v provozu neovlivněny. Modulární řešení vyžaduje minimální elektrické, magnetické a tepelné ovlivnění mezi fázemi řízení (měniče). Synchronní stroje s pulzním tokem a permanentními magnety se jeví jako atraktivní typ stroje, jejíž přednostmi jsou vysoký kroutící moment, jednoduchá a robustní konstrukce rotoru a skutečnost, že permanentní magnety i cívky jsou umístěny společně na statoru. FS-PMSM jsou poměrně nové typy střídavého stroje stator-permanentní magnet, které představují významné přednosti na rozdíl od konvenčních rotorů - velký kroutící moment, vysoký točivý moment, v podstatě sinusové zpětné EMF křivky, zároveň kompaktní a robustní konstrukce díky umístění magnetů a vinutí kotvy na statoru. Srovnání výsledků mezi FS-PMSM a klasickými motory na povrchu upevněnými PM (SPM) se stejnými parametry ukazuje, že FS-PMSM vykazuje větší vzduchové mezery hustoty toku, vyšší točivý moment na ztráty v mědi, ale také vyšší pulzaci díky reluktančnímu momentu. Pro stroje buzené permanentními magnety se jedná o tradiční rozpor mezi požadavkem na vysoký kroutící moment pod základní rychlostí (oblast konstantního momentu) a provozem nad základní rychlostí (oblast konstantního výkonu), zejména pro aplikace v hybridních vozidlech. Je předložena nová topologie synchronního stroje s permanentními magnety a spínaným tokem odolného proti poruchám, která je schopná provozu během vinutí naprázdno a zkratovaného vinutí i poruchách měniče. Schéma je založeno na dvojitě vinutém motoru napájeném ze dvou oddělených vektorově řízených napěťových zdrojů. Vinutí jsou uspořádána takovým způsobem, aby tvořila dvě nezávislé a oddělené sady. Simulace a experimentální výzkum zpřesní výkon během obou scénářů jak za normálního provozu, tak za poruch včetně zkratových závad a ukáží robustnost pohonu za těchto podmínek. Tato práce byla publikována v deseti konferenčních příspěvcích, dvou časopisech a knižní kapitole, kde byly představeny jak topologie pohonu a aplikovaná řídící schémata, tak analýzy jeho schopnosti odolávat poruchám.It has become clear that the most successful design approach involves a multiple phase drive in which each phase may be regarded as a single-module. The operation of any one module must have minimal impact upon the others, so that in the event of that module failing the others can continue to operate unaffected. The modular approach requires that there should be minimal electrical, magnetic and thermal interaction between phases of the drive. Flux-Switching permanent magnet synchronous machines (FS-PMSM) have recently emerged as an attractive machine type virtue of their high torque densities, simple and robust rotor structure and the fact that permanent magnets and coils are both located on the stator. Flux-switching permanent magnet (FS-PMSM) synchronous machines are a relatively new topology of stator PM brushless machine. They exhibit attractive merits including the large torque capability and high torque (power) density, essentially sinusoidal back-EMF waveforms, as well as having a compact and robust structure due to both the location of magnets and armature windings in the stator instead of the rotor as those in the conventional rotor-PM machines. The comparative results between a FS-PMSM and a traditional surface-mounted PM (SPM) motor having the same specifications reveal that FS-PMSM exhibits larger air-gap flux density, higher torque per copper loss, but also a higher torque ripple due to cogging -torque. However, for solely permanent magnets excited machines, it is a traditional contradiction between the requests of high torque capability under the base-speed (constant torque region) and wide speed operation above the base speed (constant power region) especially for hybrid vehicle applications. A novel fault-tolerant FS-PMSM drive topology is presented, which is able to operate during open- and short-circuit winding and converter faults. The scheme is based on a dual winding motor supplied from two separate vector-controlled voltage-sourced inverter drives. The windings are arranged in a way so as to form two independent and isolated sets. Simulation and experimental work will detail the driver’s performance during both healthy- and faulty- scenarios including short-circuit faults and will show the drive robustness to operate in these conditions. The work has been published in ten conference papers, two journal papers and a book chapter, presenting both the topology of the drive and the applied control schemes, as well as analysing the fault-tolerant capabilities of the drive.

Yahya Kemal'i yeniden yorumlamak

Taha Toros Arşivi, Dosya No: 182-Yahya Kemal Beyatlı. Not: Gazetenin "Edebiyat Notları" köşesinde yayımlanmıştır.İstanbul Kalkınma Ajansı (TR10/14/YEN/0033) İstanbul Development Agency (TR10/14/YEN/0033

The Effect of Cognitive Limb Embodiment on Vascular Physiological Response

The rubber hand illusion (RHI) is a visual-tactile perceptual illusion commonly used to study body ownership. In this paradigm, a rubber hand is positioned in front of a participant, and the person’s real hand is hidden from sight behind a barrier. When the real hand and the rubber hand are stroked synchronously, individuals perceive the rubber hand as if it were their own; it becomes “embodied.” This illusory experience of body ownership is associated with multimodal integration of touch and vision. From these visual-tactile-cognitive mechanisms, we establish that our hands belong to us when what we see matches what we feel. Recently, studies have established a correlation between the induction of the RHI and temperature changes at the skin surface. Interestingly, when the brain perceives its real limb to be “disembodied” during the cognitive illusion, the temperature of that real limb drops. The central hypothesis for the proposed study is that cognitive limb embodiment directly affects blood flow patterns; blood flow in a specific limb can be disrupted by altering the sense of the limb’s embodiment. Our rationale is that understanding the mechanisms underlying thermal-vascular regulation in healthy and diseased populations is clinically significant because blood flow can be used as a physiological marker of cognitive limb embodiment and may also be particularly important in identifying and understanding disease states. Physiological correlates of embodiment, such as temperature and blood flow changes, may have significant potential for quantitatively assessing various diseases. The first aim was to develop a modified ultrasound method to measure blood flow under the conditions of the RHI. In addition, the Doppler waveform indices were examined as physiological markers for cognitive embodiment. The second aim was to investigate the link between temperature changes and blood flow during cognitive limb embodiment. Taken together, this work seeks to provide a comprehensive understanding of the effects of cognitive limb embodiment on vascular physiological response

The Effect of Cognitive Limb Embodiment on Vascular Physiological Response

The rubber hand illusion (RHI) is a visual-tactile perceptual illusion commonly used to study body ownership. In this paradigm, a rubber hand is positioned in front of a participant, and the person’s real hand is hidden from sight behind a barrier. When the real hand and the rubber hand are stroked synchronously, individuals perceive the rubber hand as if it were their own; it becomes “embodied.” This illusory experience of body ownership is associated with multimodal integration of touch and vision. From these visual-tactile-cognitive mechanisms, we establish that our hands belong to us when what we see matches what we feel. Recently, studies have established a correlation between the induction of the RHI and temperature changes at the skin surface. Interestingly, when the brain perceives its real limb to be “disembodied” during the cognitive illusion, the temperature of that real limb drops. The central hypothesis for the proposed study is that cognitive limb embodiment directly affects blood flow patterns; blood flow in a specific limb can be disrupted by altering the sense of the limb’s embodiment. Our rationale is that understanding the mechanisms underlying thermal-vascular regulation in healthy and diseased populations is clinically significant because blood flow can be used as a physiological marker of cognitive limb embodiment and may also be particularly important in identifying and understanding disease states. Physiological correlates of embodiment, such as temperature and blood flow changes, may have significant potential for quantitatively assessing various diseases. The first aim was to develop a modified ultrasound method to measure blood flow under the conditions of the RHI. In addition, the Doppler waveform indices were examined as physiological markers for cognitive embodiment. The second aim was to investigate the link between temperature changes and blood flow during cognitive limb embodiment. Taken together, this work seeks to provide a comprehensive understanding of the effects of cognitive limb embodiment on vascular physiological response

Effect of ultra-low temperature on some mechanical properties of painted and film-coated plywood

Plywood is used for insulation systems in liquid natural gas cargo ships because of its good thermal properties. However, there are only a few research investigating the mechanical properties of plywood exposed to ultra-low temperatures. This study aims to determine how plywood reacts when exposed to ultra-low temperatures, such as - 196 °C. To achieve this purpose, the present study investigated the bending strength, modulus of elasticity, and tensile-shear strength of painted and film-coated plywood under ultra-low temperatures. The mechanical properties of plywood were discovered to be significantly impacted by the ultra-low temperature as a result of this research.. Moreover, not only the bending strength of the painted and film-coated plywood increased with decreasing temperature, but also the modules of elasticity of the painted and film-coated plywood increased. At decreasing temperature, the tensile shear strength of the painted and film-coated oven-dried plywood increased, but the ensile-shear strength of painted and film-coated air-dried plywood decreased. The tensile shear strength of air-dried plywood was determined to be more sensitive to the temperature change. Therefore, attention should be paid to plywood used in liquefied natural gas cargo ships with high humidity

Common ORL Surgical Emergencies in Sudanese Children

Background: Otorhinolaryngology (ORL) emergencies in children age group are of specific concern because they may become life threatening conditionsObjective: To obtain baseline data on the most common Otorhinolaryngology (ORL) surgical emergencies in Sudanese children in Gezira State, Sudan.Methods: This is a retrospectiveanalytic hospital based study of all children who presented with ORL surgical emergencies at the department of Ear, Nose and Throat (ENT), Wad-Medani Teaching Hospital, Gezira State, Sudan, during the period from 1st. of January 2009 to 31st. ofDecember 2010.Results: The total number of children who presented to the ENT department was 5568(31%) of the total frequency of all patients. The total number of children admissions was (54.6%) of all patients’ admissions. Emergency Surgical intervention indicated for children constituted (63.9%) of all emergency operations. Most cases (66%) occurred between the ages of six weeks to five years, with a male to female ratio of 1.15:1.0. Foreign body impaction emergencies were the most common presentation (83%) requiring surgical intervention. The sites of impaction were; the bronchus(31.45 %), the pharynx and oesophagus (22.77%), the ear (20.46%) and nose (7.26%).Conclusions: Children have always constituted a significant proportion of patients attending the general otolaryngology service. Upper aero-digestive tract foreign bodies are the most common indication for urgent surgical intervention. These emergencies are potentially life-threatening procedures with a high running cost and requiring very skilful staff and appropriate equipments. Public health education is essential in order to prevent these avoidable accidents.Key words: Otorhinolaryngology (ORL), Surgical, Emergency, Children, Foreign body (FB)