To gain a better understanding of those struggling with severe eating disorders (anorexia nervosa and bulimia nervosa), the inner life-world and subjective experiences of therapy clients were explored within the South African context. This was an empirical qualitative study. Specifically, the study’s focus was on the psychological construct of perfectionism as experienced during the respondents’ treatment resistant eating disorders. The two objectives of the research were to describe and explain perfectionism, which served to increase an overall improved understanding of perfectionism. The study’s methodology encompassed a combination of phenomenological- and grounded theory methodology, exploring the narratives of six female candidates that were undergoing individual therapy for their eating disorders. These candidates were considered to have a treatment resistant eating disorder, because they had been struggling with this diagnosis for longer than a decade, and/or had previously received multiple treatment interventions without recovering. The therapy sessions were recorded via digital audio recordings, and used in the data analysis process. The discourses pertaining to the study’s focus were transcribed and analysed using phenomenological- and grounded theory methods. The phenomenological analysis produced individual descriptions of the participants’ experiences of their perfectionism, as well as a general description for perfectionism. The grounded theory analysis produced an emerging theory in the form of a cognitive schema. This schema was named The Perfectionistic Eating Disorder Self-schema (PEDSS), and explains the inner psychological process of perfectionism within a treatment resistant eating disorder client. The results of this study, in particular the PEDSS, has implications for those trying to understand, assist, and treat those who suffer from treatment resistant eating disorders, as well as helping those who struggle with perfectionism to understand their own problem more. / Psychology / D. Phil. (Psychology)

In a rapid changing environment mining companies have to change the way in which they do business, while employees have to manage their careers and ensure they are multi-skilled. Organisations are looking to employ individuals who are career driven, highly adaptable and flexible and display the necessary employability skills. The main purpose of this study was to determine if any relationship exists between the different factors of graduate employability and work performance in the mining industry in South Africa. A cross-sectional quantitative research approach was followed. A simple random sample was drawn from graduate male and female employees between the ages of 18 – 30 years with any post-matric qualification employed in the mining industry in South Africa. Through the process of exploratory factor analysis, six graduate employability factors and four work performance factors were identified. The graduate employability factors included career self-management drive, cultural competence, career resilience, emotional literacy, career literacy and self-efficacy. The work performance factors included the supervisor role, employee role, recognition and organisation support. Correlation and regression analyses were conducted. The results indicated a relationship between graduate employability and work performance. Strong, positive correlations were found between graduate employability and work performance with career self-management drive being the strongest predictor of work performance. Recommendations for the mining industry focused on how employability could be enhanced to improve work performance. / Human Resource Management / M. Com. (Human Resource Management)

Diploma work work is bent on region management qualities. Loading and application mock - up European endowment for drive qualities EFQM to the police Czech republic. Analysis progress loading to the police practice and choice formation police Czech republic. Evaluation of the process loading and his contribution in improvement efficiency, qualities and image.

A presente pesquisa consiste num estudo sobre o processo de constituição psíquica da criança em idade escolar a partir do conceito tempo de latência, buscando articulá-lo ao processo de escolarização da infância. Situa o conceito no conjunto da obra freudiana desde seus primeiros trabalhos sobre as neuroses e a sexualidade infantil, passa pelo período de formulação da teoria das pulsões, localiza-o no contexto da teoria estrutural e, igualmente, nas reflexões de Freud acerca das relações entre natureza e cultura. Em sucessão, verifica os desdobramentos que o conceito tem na obra de reconhecidos psicanalistas que se dedicaram à análise de crianças, como Melanie Klein, Anna Freud, Donald Winnicott, Charles Sarnoff e Françoise Dolto, culminando com uma leitura do tempo de latência como um tempo lógico a partir do enfoque lacaniano. Enquanto tempo lógico infere que a latência não decorre de um processo natural, desencadeado pelo organismo, e sim pela demanda do Outro. Nesse sentido procura vinculá-lo às transformações culturais da modernidade, entre estas o processo de escolarização da infância. Sustenta que a escolarização favorece a constituição do tempo de latência, na medida em a escola se organiza como o espaço social destinado à criança, distanciando-a do ambiente familiar sem, no entanto, incluí-la no mundo adulto, ao mesmo tempo em que possibilita formas de sublimação. Entendendo o tempo de latência como uma produção do laço social, cogita que novas transformações na cultura podem extingui-lo enquanto tempo constitutivo. Aponta que fraturas na sustentação do trabalho psíquico deste tempo constitutivo aparecem em algumas formações clínicas, como a inibição intelectual e a fobia escolar. / The research consists of a study on the process of psychic constitution of the child in school age from the concept of latency time, searching the education process of infancy. It points out the concept in the set of the Freudian workmanship since the first works on the neuroses and the infantile sexuality, passes for the period of formularization of the drive theory, still locates it in the context of the structural theory and in the reflections of Freud about the relations between nature and culture. To leave of this, it verifies the unfoldings that the concept has in the workmanship of recognized psychoanalysts who had dedicated themselves to analyze of children as Melanie Klein, Anna Freud, Donald Winnicott, Charles Sarnoff and Françoise Dolto, culminating with a reading of the latency time as a logical time from the lacanian approach. While logical time understands that the latency does not elapse of a natural process, unchained for the organism, and yes for the demand of the Other. In this direction it searches to tie it to the cultural transformations of modernity, between these the education process of infancy. It supports that the education favors the constitution of the latency time, in the measure where the school is organized as the social space destined to the child, distancing itself of the familiar environment without, in meanwhile include them in the adult world, at the same time where it makes possible subliming forms. Understanding the latency time as a production of the social bow, it cogitates that new transformations in the culture can extinguish it while constituent time. It points that breakings in the sustentation of the psychic work of the latency appear in some clinical formations as the intellectual inhibition and the pertaining to school phobia.

Multilevel converters have become the direct accepted solution for high power converter applications. They are used in wide variety of power electronic applications like power transmission and distribution, electric motor drives, battery management and renewable energy management to name a few. For medium and high voltage motor drives, especially induction motor drives, the use of multilevel voltage source inverters have become indispensible. A high voltage multilevel inverter could be realized using low voltage switching devices which are easily available and are of low cost. A multilevel inverter generates voltage waveforms of very low harmonic distortion by switching between voltage levels of reasonably small amplitude differences. Thus the dv/dt of the output voltage waveform is small and hence the electromagnetic interference generated is less. Because of better quality output generation, the switching frequency of the multilevel inverters could be reduced to control the losses. Thus, a multilevel converter stands definitely a class apart in terms of performance from a conventional two-level inverter. Many multilevel inverter topologies for induction motor drives are available in the literature. The basic multilevel topologies are the neutral point clamped (NPC) inverter, flying capacitor (FC) inverter and the cascaded H-bridge (CHB) inverter. Various other hybrid multilevel topologies have been proposed by using the basic multilevel inverter topologies. It is also possible to obtain multilevel output by using conventional two-level inverters feeding an open-end winding induction motor from both sides. All the conventional multilevel voltage source inverters generate hexagonal (6 sided polygons) voltage space vector structures. When an inverter with hexagonal space vector structure is operated in the over modulation range, significant low order harmonics are generated in the phase voltage output. Over modulation operation is required for the full utilization of the available DC-link voltage and hence maximum power generation. Among the harmonics generated, the fifth and seventh harmonics are of significant magnitudes. These harmonics generate torque ripple in the motor output and are undesirable in high performance motor drive applications. The presence of these harmonics further creates problems in the closed loop current control of a motor, affecting the dynamic performance. Again, the harmonic currents generate losses in the stator windings. Therefore, in short, the presence of harmonic voltages in the inverter output is undesirable. Many methods have been proposed to eliminate or mitigate the effect of the harmonics. One solution is to operate the inverter at high switching frequency and thereby push the harmonics generated to high frequencies. The stator leakage inductance offers high impedance to the high frequency harmonics and thus the harmonic currents generated are negligible. But, high switching frequency brings switching losses and high electromagnetic interference generation in the drive system. And also, high switching frequency operation is effective only in the linear modulation range. Another solution is to use passive harmonic filters at the inverter output. For low order harmonics, the filter components would be bulky and costly. The loss created by the filters degrades the efficiency of the drive system as well. The presence of a filter also affects the dynamic performance of the drive system during closed loop operation. Special pulse width modulation (PWM) techniques like selective harmonic elimination (SHE) PWM can prevent the generation of a particular harmonic from the phase voltage output. The disadvantages of such schemes are limited modulation index, poor dynamic performance and extensive offline computations. An elegant harmonic elimination method is to generate a voltage space vector structure having more number of sides like a dodecagon (12 sided polygons) or an octadecagon (18 sided polygons) rather than a hexagon. Inverter topologies generating dodecagonal voltage space vector structure eliminate fifth and seventh order harmonics, represented as 6n 1; n = odd harmonics, from the phase voltages and hence from the motor phase currents, throughout the entire modulation range. The first harmonics appearing the phase voltage are the 11th and 13th harmonics. Another advantage is the increased linear modulation range of operation for a given DC-link voltage, because geometrically dodecagon is closer to circle than a hexagon. An octadecagonal structure eliminates the 11th and 13th harmonics as well from the phase voltage output. The harmonics present in the phase voltage are of the order 18n 1; n = 1; 2; 3; :::. Thus the total harmonics distortion (THD) of the phase voltage is further improved. The linear modulation range also gets enhanced compared to hexagonal and dodecagonal structures. Multilevel dodecagonal and octadecagonal space vector structures combines the advantages of both multilevel structure and dodecagonal and octadecagonal structure and hence are very attractive solutions for high performance induction motor drive schemes. Chapter 1 of this thesis introduces the multilevel in-verter topologies generating hexagonal, dodecagonal and octadecagonal voltage space vector structures. Inverter topologies generating multilevel dodecagonal and octadecago-nal voltage space vector structures have been proposed before but using multiple DC sources delivering active power. The presence of more than one DC source in the inverter topology makes the back to back operation (four-quadrant operation) of the drive system difficult. And also the drive system becomes more costly and bulky. This thesis proposes induction motor drive schemes generating multilevel dodecagonal and octadecagonal volt-age space vector structures using a single DC source. In Chapter 2, an induction motor drive scheme generating a six-concentric multilevel dodecagonal voltage space vector structure using a single DC source is proposed for an open-end winding induction motor. In the topology, two three-level inverters drive an open-end winding IM, one inverter from each side. DC-link of primary inverter is from a DC source (Vdc) which delivers the entire active power, whereas the secondary inverter DC-link is maintained by a capacitor at a voltage of 0:289Vdc, which is self-balanced during the inverter operation. The PWM scheme implemented ensures low switching frequency for primary inverter. Secondary inverter operates at a small DC-link voltage. Hence, switching losses are small for both primary and secondary inverters. An open-loop V/f scheme was used to test the topology and modulation scheme. In the work proposed in Chapter 3, the topology and modulation scheme used in the first work is modified for a star connected induction motor. Again, the scheme uses only a single DC source and generates a six-concentric multilevel space vector struc-ture. The power circuit topology is realized using a three-level flying capacitor (FC) inverter cascaded with an H-bridge (CHB). The capacitors in the CHB inverter are maintained at a voltage level of 0:1445Vdc. The FC inverter switches between volt-age levels of [Vdc; 0:5Vdc; 0] and the CHB inverter switches between voltage levels of [+01445Vdc; 0; 0:1445Vdc]. The PWM scheme generates a quasi-square waveform output from the FC inverter. This results in very few switchings of the FC inverter in a funda-mental cycle and hence the switching losses are controlled. The CHB inverter switches Ch. 0: at high frequency compared to the FC inverter and cancels the low order harmonics (6n 1; n = odd) generated by the FC inverter. Even though the CHB operates at higher switching frequency, the switchings are at low voltage thereby controlling the losses. The linear modulation range of operation is extended to 48:8Hz for a base frequency of 50Hz. An open-loop V/f scheme was used to test the topology and modulation scheme. In Chapter 4, a nine-concentric multilevel octadecagonal space vector structure is proposed for the first time, again using a single DC source. The circuit topology remains same as the work in Chapter 3, except that the CHB capacitor voltage is maintained at 0:1895Vdc. The 5th; 7th; 11th and 13th harmonics are eliminated from the phase voltage output. The linear modulation range is enhanced to 49:5Hz for a base speed of 50Hz. An open-loop V/f scheme and rotor field oriented control scheme were used to test the proposed drive system. All the proposed drive schemes have been extensively simulated and tested in hard-ware. Simulation was performed in MATLAB-SIMULINK environment. For implement-ing the inverter topology, SKM75GB12T4 IGBT modules were used. The control al-gorithms were implemented using a DSP (TI’s TMS320F28334) and an FPGA (Xilinx Spartan XC3S200). A 1kW , 415V , 4-pole induction motor was used for the experiment purpose. The above mentioned induction motor drive schemes generate phase voltage outputs in which the low order harmonics are absent. The linear modulation range is extended near to the base frequency of operation compared to hexagonal space vector structure. In the inverter topologies, the secondary inverters or the CHB inverters functions as harmonic filters and delivers zero active power. The primary inverter in the topologies switches at low frequency, reducing the power loss. Single DC source requirement brings down the cost of the system as well as permitting easy four-quadrant operation. This is also advantageous in battery operated systems like EV applications. With these features and advantages, the proposed drive schemes are suitable for high performance, medium voltage induction motor drive applications.

Ce travail de recherche est une généalogie de la notion de « désir sexuel » telle qu'elle fut conçue dans le christianisme antique du IIIe au Ve siècle. À partir de la distinction entre deux anthropologies concurrentes, nous cherchons à reconstituer les modalités selon lesquelles ce désir a été pensé comme une pulsion irrésistible. Nous nous inscrivons donc dans la tradition des études de genre puisque nous posons la question de savoir s'il existe, au fondement des catégorisations sociales et des modes de légitimation du pouvoir, une forme de naturalité irréductible. Notre objectif est de mettre en évidence, d'une part, en quoi l'idée de désir naturel est une forme de problématisation contingente du désir sexuel et, d'autre, part, les conséquences de cette façon de penser. Entre le IIIe et le Ve siècle, les auteurs chrétiens s'opposent en ce qui concerne la question des capacités humaines. Pour les « perfectionnistes », l'homme est capable d'accéder par ses propres forces à la perfection. Par conséquent, le « monde » est pensé par eux comme un ensemble de liens qui entravent l'itinéraire spirituel du sujet. La solitude du « désert » apparaît alors dans ce cadre problématique comme un moyen d'accéder à la liberté. Au contraire, pour les « défaillantistes », l'homme est par nature infirme, si bien que la perfection est conçue non plus comme ce à quoi il peut lui-même accéder, mais comme un don de Dieu. En soulignant que l'homme n'est pas le maître dans sa propre maison puisqu'il ne peut maîtriser sa libido, Augustin montre que sa libération n'est envisageable qu'au prix de sa soumission à des institutions coercitives ayant pour fonction de compenser sa faiblesse. Proposant une forme originale de problématisation de la nature humaine en naturalisant la pulsion sexuelle, le défaillantisme chrétien permet donc de justifier la soumission des hommes. En faisant la généalogie du désir sexuel, ce travail s'emploie à montrer que la liberté ne requiert pas seulement une critique de l'idée de répression, mais une remise en cause plus fondamentale du modèle naturaliste de la pulsion. / This thesis is a genealogical study of the notion of “sexual desire” as it appeared in Ancient Christianity from the 3rd to the 5th century. Distinguishing between two competing anthropologies, it seeks to reconstruct the modalities according to which this desire has been understood as a compelling drive. It is in line with gender studies in so far as it asks the question of whether there is, at the basis of social categories and justifications of power, a form of irreducible naturality. The purpose here is, on one hand, to show that the notion of natural desire derives from a contingent problematization of sexual desire and, on the other hand, to highlight the consequences of this reasoning. Between the 3rd and 5th centuries, Christian authors opposed one another on the question of human capabilities. For the “perfectionists,” man was able to achieve perfection on his own. Consequently, they saw the “world” as full of bonds hindering the subject's spiritual progress. In this context, being alone in the “desert” appeared as a means to achieve freedom. On the contrary, the “defaultists” held that man was naturally flawed, so that perfection was not thought to be an achievable goal any more, but a gift from God. Underlining that man was no master in his own house because he could not master his own libido, Augustine showed that his liberation could only depend on his submitting to coercive institutions designed to compensate for his weakness. Offering an original problematization of human nature by naturalizing the sexual drive, Christian defaultism could thus justify the submission of men. By tracing a genealogy of sexual desire, this study seeks to demonstrate that freedom does not only require criticizing the idea of repression, but more radically questionning the naturalist model of the drive.

In the present work a simulation model for examining the fundamental dynamic behaviour of a servo driven powertrain is developed. This powertrain consists of a permanent magnet synchronous motor, a cycloidal gearbox and a torque motor to apply a load. On basis of this model the selection of components for the design of a test rig is possible. This leads to the constructive draft of the test rig. In order to model the system, the fundamentals give a brief overview of the components incorporated in the test rig system. With ais of the specified task the simulation purpose is defined and the modelling process enabled. The subsequent system analysis is performed intensively to decompose the system into subsystems, which are then investigated to find the optimal modelling approach for the given simulation task. Particular emphasis is put on the investigation of the cycloidal gearbox subsystem and it shows, that approaches for modelling the dynamic behaviour of the gearbox as a whole have only been published partially. Therefore, the available modelling approaches are analysed and suitable models are developed as conceptual models. Those will be formalised and implemented in Matlab/Simulink. The model is verified and simulation experiments are performed, that help in the selection of suitable test rig components. On basis of a flexible test rig, finally the constructive draft is presented.

A presente pesquisa consiste num estudo sobre o processo de constituição psíquica da criança em idade escolar a partir do conceito tempo de latência, buscando articulá-lo ao processo de escolarização da infância. Situa o conceito no conjunto da obra freudiana desde seus primeiros trabalhos sobre as neuroses e a sexualidade infantil, passa pelo período de formulação da teoria das pulsões, localiza-o no contexto da teoria estrutural e, igualmente, nas reflexões de Freud acerca das relações entre natureza e cultura. Em sucessão, verifica os desdobramentos que o conceito tem na obra de reconhecidos psicanalistas que se dedicaram à análise de crianças, como Melanie Klein, Anna Freud, Donald Winnicott, Charles Sarnoff e Françoise Dolto, culminando com uma leitura do tempo de latência como um tempo lógico a partir do enfoque lacaniano. Enquanto tempo lógico infere que a latência não decorre de um processo natural, desencadeado pelo organismo, e sim pela demanda do Outro. Nesse sentido procura vinculá-lo às transformações culturais da modernidade, entre estas o processo de escolarização da infância. Sustenta que a escolarização favorece a constituição do tempo de latência, na medida em a escola se organiza como o espaço social destinado à criança, distanciando-a do ambiente familiar sem, no entanto, incluí-la no mundo adulto, ao mesmo tempo em que possibilita formas de sublimação. Entendendo o tempo de latência como uma produção do laço social, cogita que novas transformações na cultura podem extingui-lo enquanto tempo constitutivo. Aponta que fraturas na sustentação do trabalho psíquico deste tempo constitutivo aparecem em algumas formações clínicas, como a inibição intelectual e a fobia escolar. / The research consists of a study on the process of psychic constitution of the child in school age from the concept of latency time, searching the education process of infancy. It points out the concept in the set of the Freudian workmanship since the first works on the neuroses and the infantile sexuality, passes for the period of formularization of the drive theory, still locates it in the context of the structural theory and in the reflections of Freud about the relations between nature and culture. To leave of this, it verifies the unfoldings that the concept has in the workmanship of recognized psychoanalysts who had dedicated themselves to analyze of children as Melanie Klein, Anna Freud, Donald Winnicott, Charles Sarnoff and Françoise Dolto, culminating with a reading of the latency time as a logical time from the lacanian approach. While logical time understands that the latency does not elapse of a natural process, unchained for the organism, and yes for the demand of the Other. In this direction it searches to tie it to the cultural transformations of modernity, between these the education process of infancy. It supports that the education favors the constitution of the latency time, in the measure where the school is organized as the social space destined to the child, distancing itself of the familiar environment without, in meanwhile include them in the adult world, at the same time where it makes possible subliming forms. Understanding the latency time as a production of the social bow, it cogitates that new transformations in the culture can extinguish it while constituent time. It points that breakings in the sustentation of the psychic work of the latency appear in some clinical formations as the intellectual inhibition and the pertaining to school phobia.

In DC to AC power conversion, voltage source inverters (VSI) based current controllers are usually preferred for today’s high performance AC drive which requires excellent dynamic and steady state performances at different transient and load conditions, with the additional advantages like inherent short circuit and over current protection. Out of different types of current controllers, hysteresis controllers are widely used due to their simplicity and ability to meet the requirements for a high performance AC drives. But the conventional hysteresis controllers suffers from wide variation of PWM switching frequency, overshoot in current errors, sub-harmonic components in the current waveform and non-optimum switching at different operating point of the drive system. To mitigate these problems, particularly to control the switching frequency variation, which is the root cause of all other problems, several methodologies like ramp comparison based controller, predictive current controller, etc. were proposed in the literature. But amplitude and phase offset error in the ramp comparison based controllers and complexities involved in the predictive controllers have limited the use of these controllers. Moreover, these type of controllers, which uses three separate and independently controlled tolerance band (sinusoidal type or adaptive) to control the 3-phase currents, shows limited dynamic responses and they are not simple to implement. To tackle the problem of controlling 3-phase currents simultaneously, space vector based hysteresis current controller is very effective as it combines the current errors of all the three phases as a single entity called current error space vector. It has a single controller’s logic with a hysteresis boundary for controlling this current error space vector. Several papers on space vector based hysteresis controllers for 2-level inverter with constant switching frequency have been published, but the application of the constant switching frequency based hysteresis current controllers for multi¬level inverter fed drive system, has not been addressed properly. Use of multi-level inverter in modern high performance drive for medium and high voltage levels is more prominent because of multi-level’s inherent advantages like good power quality, good electromagnetic compatibility (EMC), better DC link voltage utilization, reduced device voltage rating, so on. Even though some of the earlier works describe three-level space vector based hysteresis current controller techniques, they are specific to the particular level of inverters and does not demonstrate constant switching frequency of operation. This thesis proposes a novel approach where nearly constant switching frequency based hysteresis controller can be implemented for any general n-level inverter and it is also independent of inverter topology. In this work, varying parabolic boundary is used as the hysteresis current error boundary for controlling the current in a multi-level space vector structure. The computation of the parabolic boundary is accomplished offline and all the necessary boundary parameters at different operating points are stored in the look-up tables. The varying parabolic boundary for the multi-level space vector structure depends on the sampled reference phase voltage values which are estimated from stator current error information and then using the equivalent circuit model of induction motors. Here, a mapping technique is adopted to bring down all the three phase references to the inner- most carrier region, which results in mapping any outer triangular structure where tip of the voltage space vector is located, to one of the sectors of the inner most hexagon of the multi-level space vector structure. In this way, the required mapped sector information is easily found out to fix the correct orientation of the parabolic boundary in the space vector plane. This mapping technique simplifies the controller’s logic similar to that of a 2-level inverter. For online identification of the inverter switching voltage vectors constructing the present outer triangle of the multi-level space vector structure, the proposed controller utilizes the sampled phase voltage references. This identification technique is novel and also generic for any n-level inverter structure. This controller is having all the advantages of a space vector based hysteresis current controller and that of a multi-level inverter apart from having a nearly constant switching frequency spectrum similar to that of a voltage controlled space vector PWM (VC-SVPWM). Using the proposed controller, simulation study of a five-level inverter fed induction motor (IM) drive scheme, was carried out using Matlab-Simulink. Simulation study showed that the switching frequency variations in a fundamental cycle and over the entire speed range of the linear modulation region, is similar to that of a VC-SVPWM based multi-level VSI. The proposed hysteresis controller is experimentally verified on a 7.5 kW IM vector control drive fed with a five-level VSI. The proposed current error space vector based hysteresis controller providing nearly constant switching frequency is implemented on a TI TMS320LF2812 DSP and Xilinx XC3S200FT256 FPGA based platform. The three-phase reference currents are generated depending on the frequency command and the controller is tested with the drive for the entire operating speed range of the machine in forward and reverse directions. Steady state and quick transient results of the proposed drive are presented in this thesis. This thesis also proposes another type of hysteresis controller, firstly for 2-level inverter and then for general n-level multi-level inverter, which eliminates the parabolic boundary and replaces it with a boundary which is computed online and does not use any look up table for boundary selection. The current error boundary for the proposed hysteresis controller is computed online in a very simple way, using the information of estimated fundamental stator voltages along α and β axes of space vector plane. The method adopted for the proposed controller to compute the boundary does not involve any complicated computations and it selects the optimal vector for switching when current error space vector crosses the boundary. This way adjacent voltage vector switching similar to VC-SVPWM can be ensured. For 2-level inverter, it precisely determines the sector, in which reference voltage vector is present. In multi-level inverter, this controller also finds out the mapped sector information using the same mapping techniques as explained in the first part of this thesis. In both 2-level and multi-level inverter, the proposed controller does not use any look up table for finding individual voltage vector switching times from the estimated voltage references. These switching times are used for the computation of hysteresis boundary for individual vectors. Thus the hysteresis boundary for individual vectors is exactly calculated and the boundary is similar to that of VC-SVPWM scheme for the respective levels of inverter. In the present scheme, the phase voltage harmonic spectrum is very close to that of a constant switching frequency VC-SVPWM inverter. In this thesis, at first, the proposed on line boundary computation scheme is implemented for a 2-level inverter based controller for the initial study, so that it can be executed as fast as 10 µs in a DSP platform, which is required for accurate current control. Then the same algorithm of 2-level inverter is extended for multi-level inverter with the additional logic for online identification of nearest switching voltage vectors (also used in the parabolic boundary case) for the present sampling interval. Previously mentioned mapping technique for multi-level inverter, is also implemented here to bring down the phase voltage references to the inner-most carrier region to realize the multi-level current control strategy equivalent to that of a 2-level inverter PWM current control. Simulation study to verify the steady state as well as transient performance of the proposed controller for both 2-level as well as five-level VSI fed IM drive is carried out using Simulink tool box of MATLAB Simulation Software. The proposed hysteresis controllers are experimentally verified on a 7.5 kW IM vector control drive fed with a two-level VSI and five-level VSI separately. The proposed current error space vector based hysteresis controller providing nearly constant switching frequency profile for phase voltage is implemented on the TI TMS320LF2812 DSP and Xilinx XC3S200FT256 FPGA based platform. The three-phase reference currents are generated depending on the frequency command and the proposed hysteresis controllers are tested with drive for the entire operating speed range of the machine in forward and reverse directions. Steady state and transient results of the proposed drive are also presented for different operating conditions, through the simulation study followed by experimental verifications. Even though the simulation and experimental verifications are done on a 5-level inverter to explain the proposed hysteresis controller, it can be easily implemented for any general n-level inverter, as described in this thesis.

Datormoln, även kallat molnet, är teknik baserad på användande av applikationer och data över Internet. Molnet erbjuder olika typer av tjänster och resurser som t.ex. applikationer och datorkraft. Molntjänster kan underlätta för företag då de kan sänka den annars höga kostnaden för saker som personal, hårdvara, mjukvara och det utrymme detta kräver. Denna rapport kommer svara på frågan ”Vad är moln?” och grundläggande beskriva molnets struktur och funktion, samt olika typer av moln. Rapporten kommer även beskriva ett par olika molntjänster.