The flux-weakening control (FWC) methods for interior permanent magnet synchronous motors (IPMSMs) with torque performance improvement are studied in this thesis. A FWC strategy with constant parameters is proposed, which achieves the extended dc-link voltage utilization and improves the tracking performance. The voltage trajectory is extended to the overmodulation region to increase the dc-link voltage utilization rate and torque. Moreover, a current predictive controller is implemented to improve tracking performance. A FWC method considering the resistive voltage drop and magnetic saturation is proposed. The proposed method achieves the voltage extension, torque improvement, and improved dynamic performance by establishing a new stator flux linkage adjustment method. The stator flux linkage reference is adjusted based on the torque reference, operating speed, and modulation index. Two voltage feedback paths are established and chosen based on the torque reference and operating speed. The stator resistance and nonlinear inductance characteristics are constructed based on the experimental test. Thus, accurate current control is achieved. Compared to feedforward-based FWC methods, the proposed method improves the output torque and power. Compared to feedback-based FWC methods, the proposed method improves the dynamic performance and avoids the voltage saturation and windup problem. Compared to the mixed FWC methods, which only have one feedback path, the proposed method improves the dynamic performance. The influence of extended dc-link voltage utilization is analyzed. The nonlinear relationship between voltage and torque is solved mathematically. The torque, torque ripple, and current ripple trends with modulation index in voltage extension region are analyzed, and the harmonic spectra of voltage, current, and torque with or without voltage extension are compared, which provide the guidance to make the tradeoff between maximizing the torque and torque ripple alleviation. / Thesis / Master of Applied Science (MASc)

Frictional measurements were made on natural fault gouge at seismic slip rates using a high-speed rotary-shear apparatus to study effects of slip velocity, acceleration, displacement, normal stress, and water content. Thermal-, mechanical-, and fluid-flowcoupled FEM models and microstructure observations were implemented to analyze experimental results. Slightly sheared starting material (Unit 1) and a strongly sheared and foliated gouge (Unit 2) are produced when frictional heating is insignificant and the coefficient of sliding friction is 0.4 to 0.6. A random fabric gouge with rounded prophyroclasts (Unit 3) and an extremely-fine, microfoliated layer (Unit 4) develop when significant frictional heating occurs at greater velocity and normal stress, and the coefficient of sliding friction drops to approximately 0.2. The frictional behavior at coseismic slip can be explained by thermal pressurization and a temperature-dependent constitutive relation, in which the friction coefficient is proportional to 1/T and increases with temperature (temperature-strengthening) at low temperature conditions and decreases with temperature (temperature-weakening) at higher temperature conditions. The friction coefficient, normal stress, pore pressure, and temperature within the gouge layer vary with position (radius) and time, and they depend largely on the frictional heating rate. The critical displacement for dynamic weakening is approximately 10 m or less, and can be understood as the displacement required to form a localized slip zone and achieve a steady-state temperature condition. The temporal and spatial evolution of hydromechanical properties of recovered from the Nankai Trough (IODP NanTroSEIZE Stage 1 Expeditions) have been investigated along different stress paths, which simulate the natural conditions of loading during sedimentation, underthrusting, underplating, overthrusting, and exhumation in subduction systems. Porosity evolution is relatively independent of stress path, and the sediment porosity decreases as the yield surface expands. In contrast, permeability evolution depends on the stress path and the consolidation state, e.g., permeability reduction by shear-enhanced compaction occurs at a greater rate under triaxialcompression relative to uniaxial-strain and isotropic loading. In addition, experimental yielding of sediment is well described by Cam-Clay model of soil mechanics, which is useful to better estimate the in-situ stress, consolidation state, and strength of sediment in nature.

This dissertation is a proposal for foot structure in Québécois that uniformly accounts for high vowel distribution with respect to tenseness, devoicing and deletion within a single prosodic framework. The complementary distribution of tenseness in the final syllable and the variable realizations in the non-final syllable are shown to be regulated by the proposed foot structure. A grammatical, sonority-based surface weight distinction is assumed for vowels: tense high vowels are associated to a full mora µ, along with non-high vowels, while lax high vowels are associated to a hypomora λ, a weight value less than µ. This grammatical weight is regulated at the level of the minimally monomoraic foot. The final, Head Foot is necessarily monosyllabic. Thus, a final hypomoraic rime is quantitatively insufficient to host a foot projection, resulting in a monomoraic, tense vowel in an open syllable. The foot expands to include an adjacent syllable in words consisting of more than two syllables, following the Trochaic Markedness Hierarchy, based on the following three principles, in the order of priority: 1) quantitative minimum: light and heavy rimes are preferred to superlight (λ) rimes, 2) quantitative evenness: even trochees are preferred to uneven trochees, and 3) quantitative dominance: the left branch that is heavier than the right branch is preferred to the left branch that is lighter. A form like /kamizᴐl/ surfaces with a monomoraic, tense vowel in the left branch of the trochee, (ska. wmi)(szᴐl), given that an even foot (L L) is preferred to an uneven foot with a hypomoraic branch, (L SL). The trochaic instantiation (H) is also better-formed than (L SL), preferring deletion to a hypomoraic rime: (kam)(zᴐl). In the Optimality-theoretic analysis, variation is modeled via the mechanism of a Floating Constraint (Reynolds 1994): a constraint whose ranking status can be varied with respect to a set range of a fixed ranking of constraints, within a single grammar. The variation in question is shown to be largely a function of the floating status of the constraint regulating the grammatical weight association of vowels, (Son-Weight), and its relative ranking with respect to the Trochaic Markedness constraints. / text

Recent earthquakes have highlighted the vulnerability of existing structure to seismic loading. Current seismic retrofit strategies generally focus on increasing the strength/stiffness in order to upgrade the seismic performance of a structure or element. A typical drawback of this approach is that the demand on the structural and sub-structural elements can be increased. This is of particular importance when considering the foundation capacity, which may already be insufficient to allow the full capacity of the existing wall to develop (due to early codes being gravity load orientated). In this thesis a counter intuitive but rational seismic retrofit strategy, termed "selective weakening" is introduced and investigated. This is the first stage of an ongoing research project underway at the University of Canterbury which is focusing on developing selective weakening techniques for the seismic retrofit of reinforced concrete structures. In this initial stage the focus is on developing selective weakening for the seismic retrofit of structural walls. This is performed using a series of experimental, analytical and numerical investigations. A procedure for the assessment of existing structural walls is also compiled, based on the suggestions of currently available code provisions. A selective weakening intervention is performed within an overall performance-based retrofit approach with the aim of improving the inelastic behaviour by first reducing the strength/stiffness of specific members within the structural system. This will be performed with the intention of modifying a shear type behaviour towards a flexural type behaviour. As a result the demand on the structural member will be reduced. Once weakening has been implemented the designer can use the wide range of techniques and materials available (e.g. use of FRP, jacketing or shotcrete) to ensure that adequate characteristics are achieved. Whilst performing this it has to be assured that the structure meets specific performance criteria and the principles of capacity design. A target of the retrofit technique is the ability to introduce the characteristics of recently developed high performance seismic resisting systems, consisting of a self centring and dissipative behaviour (commonly referred to as a hybrid system). In this thesis, results of experimental investigations performed on benchmark and selectively weakened walls are discussed. The investigations consisted of quasi-static cyclic uni-directional tests on two benchmark and two retrofitted cantilever walls. The first benchmark wall is detailed as typical of pre-1970's construction practice. An equivalent wall is retrofitted using a selective weakening approach involving a horizontal cut at foundation level to allow for a rocking response. The second benchmark wall represents a more severe scenario where the inelastic behaviour is dominated by shear. A retrofit solution involving vertically segmenting the wall to improve the ductility and retain gravity carrying capacity by inducing a flexural response is implemented. Numerical investigations on a multi-storey wall system are performed using non linear time history analysis on SDOF and MDOF lumped plasticity models, representing an as built and retrofitted prototype structure. Calibration of the hysteretic response to experimental results is carried out (accounting for pinching and strength degradation). The sensitivity of maximum and residual drifts to p-delta and strength degradation is monitored, along with the sensitivity of the peak base shear to higher mode affects. The results of the experimental and analytical investigations confirmed the feasibility and viability of the proposed retrofit technique, towards improving the seismic performance of structural walls.

The phenomenon of /s/ weakening is common among many varieties of Spanish, from Latin America to southern Spain (Lipski (2011), Samper Padilla (2011)). This project will focus specifically on coda /s/ weakening in Andalusian Spanish, the social factors that influence it, and the language ideologies surrounding the dialect. Previous research has found that social factors influencing /s/ weakening include social class, gender, and education level (Lipski (2011), Samper Padilla (2011), Holmquist (2008), Terrell (1981), Fontanella de Weinberg (1973)). Studies on /s/ weakening in Andalusian Spanish have mainly focused on the functional compensation for the loss of /s/, but little research has been found on the social factors conditioning /s/ weakening in Andalusian Spanish (Rincon-Perez (2015), Carlson (2006), Ranson (1993), and more). This study will examine how the social factors of gender and class influence the presence of /s/ weakening in participants from Granada. Traditionally in studies of /s/ weakening, the discussion of variation has been limited to the categories of retention, aspiration, or deletion. However, this approach does not fully encompass the entire possibility of variety for /s/ because not all tokens of /s/ are equal in strength. By using the acoustic measurements of center of gravity (COG) and duration as continuous variables, /s/ weakening can be analyzed more precisely and comprehensively (Erker (2010), File-Muriel & Brown (2011)). Data for this research project was gathered in person from ten university-aged Andalusian Spanish speakers (5 female, 5 male) in Granada, Spain. Participants completed a demographic survey, reading passage, and participated in a thirty-minute sociolinguistic interview which included questions about participants’ language ideologies. Data was analyzed by measuring the duration and COG of all tokens of coda /s/ in participants’ speech using a Praat script. Statistical analysis was performed in RBrul to determine the relevant social and linguistic factors influencing /s/ weakening. Results showed that there was a significant correlation between duration and social class, as well as between duration and token position in word and phrase. No significant correlation between COG and any of the social or linguistic variables was found. The language ideologies of participants were also analyzed, and the results revealed that participants were generally aware of their distinctive dialect and its negative perceptions and that the majority of participants said that they had been judged for the way that they talked. These results are mostly consistent with the previous research, but the lack of correlation between COG and any of the variables was surprising.

Tropical cyclone (TC) rapid intensity change negatively impacts forecast error. Many studies have investigated rapid intensification, but fewer explore rapid weakening, particularly with aircraft observations due to fewer weakening TCs being flown. This study assesses factors contributing to the rapid weakening of Hurricane Lorenzo (2019) and the comparatively slower weakening of Hurricane Florence (2018) using aircraft observations and satellite-based products to enhance understanding of processes related to TC weakening. Intrusion of environmental dry air into Lorenzo's core under persistent moderate vertical wind shear, in conjunction with quickly decreasing SSTs, largely contributed to the TC's rapid weakening. Conversely, SSTs were higher and decreased more slowly along Florence's track, and dry air did not reach the TC's core. Confirming these processes with both aircraft and satellite observations implies that satellite analysis in the absence of reconnaissance could detect these features to some extent which may support future operational forecasting.

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<p>This thesis presents the study and the design analysis of apermanent magnet synchronous motor (PMSM) for the tractionapplication of an electric vehicle. An existing inductiontraction motor for an electric forklift benchmarks the expectedperformances of the proposed PMSM design. Further, thepossibility of using the identical stator as the one used inthe induction motor is explored for the fast prototyping. Theprototype motor is expected to be field-weakened and to have aconstant power speed range (CPSR) of 2.5 to 3.</p><p>A design approach based on the CPSR contour plot in aninterior permanent magnet (IPM) parameter plane is derived toobtain the possible designs that meet all the designspecifications and the targeted CPSR. This study provides thepossible alternative designs for the subsequent futureprototype motors.</p><p>An analytical approach to estimate the iron loss in PMsynchronous machines is developed and included in the designprocedure. The proposed technique is based on predicting theflux density waveforms in the various regions of the machine.The model can be applied at any specified load condition,including the field-weakening operation region. This model canbe ultimately embedded in the design process for a routine usein loss estimations.</p><p>The first prototype motor with an inset permanent magnetrotor has been built and the available measurements are used tovalidate the design performance. In particular, the thermalanalyses based both on the lumped-circuit approach and thenumerical method are compared with the measured results. Asecond and possibly a third prototype motor targeting a widerand higher performance will be carried out in the continuingphase of the project.</p><p><b>Keywords:</b>Constant Power Speed Range, Electric Vehicles,Field-weakening, Reference Flux Linkage, Iron Loss, PermanentMagnet Synchronous Motor, Thermal Analysis</p>

Les périphrases verbales hésitent entre lexique et grammaire. Nous avons choisi d'analyser celles construites sur "aller", "venir" et "être en train de" sous un angle diachronique, de l'origine à nos jours. Ainsi, divers thèmes seront abordés : la question de la grammaticalisation, le choix entre auxiliaire et semi-auxiliaire, l'affaiblissement sémantique, la question de l'auxiliarisation...Les formes prépositionnelles sont étudiées, avec un souci particulier accordé au rôle des prépostitions en question. Nous interrogerons également le statut de ces formes verbales par rapport au système des temps, et nous verrons dans quelle mesure elles sont en concurrence avec certains de ces temps. Par ailleurs, nous nous demanderons si ces périphrases sont à même d'intégrer le système verbal français et, le cas échéant, si elles peuvent acquérir le statut de temps à part entière. / Verbal circumlocutions hesitate between lexicon and grammar. We analyze those construct on the verbs "aller" "venir" and "être en train de" under the angle diachronic, from its origins to the Present day. So, diverse themes will be approach : question of grammaticalization, choice between auxiliary and semi-auxiliary, semantic weakening, question of auxiliarization...The prespositional forms are study, which a particular concern granted in role of presposition in quest.