La topologie onduleur à six bras associé à une machine triphasée à phases indépendantes a la propriété de d'offrir, dans le cadre applicatif de l'automobile, une double fonctionnalité, traction et chargeur forte puissance. Cet avantage nécessite, par contre, le contrôle des composantes homopolaires classiquement nulles lors de la présence d'un couplage en étoile. Cette thèse propose alors, d'une part une étude et une modélisation des onduleurs multi-bras et, d'autre part, développe des stratégies de contrôle-commande adaptées à la présence des grandeurs homopolaires. Les algorithmes de commande classiques de l'onduleur sont comparés et une stratégie vectorielle originale, dite Z-SVM permettant d'annuler le courant homopolaire haute fréquence, est développée. Enfin, il est montré comment la gestion des composantes homopolaires aux valeurs moyennes permet d'accroître les performances de l'ensemble à faible comme à haute vitesse, en jouant sur les zones avant et après défluxage des caractéristiques couple-vitesse. Les solutions proposées sont validées sur un banc expérimental composé d'une machine prototype spécialement développée pour une application automobile et alimentée par un onduleur six-bras commandé par des composants de type FPGA. Les stratégies proposées sont comparées en termes de performances et de complexité algorithmique. / For an automotive application, a six leg-VSI connected to a three-phase open-end winding machine has the ability to offer a dual-function. In this case, an additional zero-sequence component, usually absent when a star-coupling is used, needs to be controlled. Firstly, a study, modeling and control of a multi-leg inverter are proposed. Secondly, control structures capable of handling the presence of zero-sequence components are investigated. The conventional control algorithms applied to the inverter are analyzed and an original vector control strategy, called Z-SVM, capable to cancel the high frequency zero-sequence current is developed. Finally, it is shown how the management of the zero-sequence components enhances the performance of the drive at low as well as at high-speed, corresponding on the areas of the torque-speed characteristics before and after flux weakening. The proposed solutions are validated on an experimental test bench consisting of a machine prototype especially developed for automotive application and powered by a six-leg inverter controlled by an FPGA-based device. The proposed strategies are compared in terms of performance and computational complexity.

A split-phase induction motor (SPIM) is obtained by splitting each of the three-phase stator windings of an induction motor into two equal halves. This results in two sets of three-phase windings with a spatial angle difference of 30◦ (electrical) between them. The two sets of windings are fed from two different voltage-source inverters for speed control of the split-phase motor drive. Low dc bus voltage requirement and improved torque profile are some of the advantages of the split-phase motor, compared to the normal three-phase induction motor. A pulse width modulation (PWM) technique is used to produce the gating signals for the power semiconductor devices in the two inverters. The PWM technique can either be a carrier comparison (CC) based method or a space-vector (SV) based scheme. The carrier based PWM methods employ six modulating waves, which are compared against a common triangular carrier to generate the gating pulses. In space-vector based PWM schemes, the voltage reference is specified in terms of a rotating reference vector. In each subcycle, a set of voltage vectors are applied for appropriate durations of time to produce an average vector equal to the reference vector. Unlike three-phase induction motor drives, where the voltage vectors are two dimensional, the voltage vectors in the case of SPIM drive are four dimensional. This thesis presents a detailed survey on carrier-comparison based and space-vector based PWM techniques for the SPIM drive. In this thesis, sine-triangle PWM (STPWM) is analyzed from a space-vector perspective. The set of voltage vectors applied and the sequence of application of the voltage vectors in each half-carrier cycle are studied. The analysis shows that the set of voltage vectors and the switching sequence employed by STPWM are different from those used by the well known SVPWM tech-niques. Two other CC based PWM techniques, based on common mode injection, are considered for the SPIM drive. In one method, the common-mode signal is derived from all the six modulating signals, and is the same for both the inverters. In the second method, the common-mode signal is different for the two inverters; each common-mode signal is derived from the three-phase sinusoidal signals of the respective inverter. The study shows that the latter method has the highest dc bus utilization and results in the lowest total harmonic distortion (THD) among the CC PWM techniques. An experimental comparison of the three carrier-comparison techniques with three well known space-vector PWM techniques is presented. Total harmonic distortion (THD) of the line current is measured at different modulation indices for all six techniques. The experimental results are obtained from a 6kW, 200V, 50Hz split-phase induction motor drive, with constant V /F ratio. The PWM techniques are implemented using an ALTERA cyclone II field programmable gate array (FPGA) digital controller. One of the SV techniques, termed here as 4-dimensional 24-sector (4D24SEC) PWM is found to be the best in terms of line current THD among all the CC and SV based PWM techniques considered. However, compared to any carrier-based technique, implementation of the 4D24SEC PWM based on the space vector approach is found to be resource intensive. Hence, an equivalent carrier-based implementation of 4D24SEC PWM is proposed in this thesis. The feasibility of the proposed approach is verified experimentally, and is found to be consuming much less logical resources than the space-vector implementation (i.e. 4102 logical elements for the CC approach as against 33,655 logical elements for the SV approach). A new space-vector PWM technique is also proposed in the thesis. This technique utilizes a new set of voltage vectors and a new switching sequence, which are motivated by the analyses of the carrier-based methods, presented earlier. The proposed technique is implemented, and is compared with other space-vector and carrier-based methods at different modulation indices and switching frequencies. The proposed PWM technique is found to have the same dc-bus utilization as the existing 4-dimensional SV based PWM techniques. The performance of the proposed method is found to be not better than existing 4-dimensional SV PWM methods. The possibilities for new switching sequence is being explored here.

Produzierende Unternehmen benötigen Lösungen, um neue Produkte immer schneller auf den Markt zu bringen und wettbewerbsfähig zu bleiben. Die Herausforderung dabei ist, dass die drei OEE-Komponenten Verfügbarkeit, Performance und Qualität im Vergleich zur reinen Serienproduktion nicht sinken. Es muss zudem ein attraktiver Return of Investment (ROI) und eine möglichst niedrige Time-to-Market (TTM) für neue Produkte oder Produktänderungen gewährleistet sein. Nur so lässt sich die Individualisierung von Massenprodukten im großen Stil wirtschaftlich umsetzen. Die Digitalisierung aber reicht nicht aus, um beide Anforderungen zugleich umzusetzen. Dazu gehören auch intelligente Transportsysteme, mit denen sich adaptive Maschinen und Anlagen für eine flexible und wirtschaftliche Produktion herstellen lassen. [... aus dem Text]

At present, one of the main issues in electric power networks is the reduction in conventional generation and its replacement by low inertia renewable energy generation. The balance between generation and demand has a direct impact on the system frequency and system inertia limits the frequency rate of change until compensation action can be undertaken. Traditionally generation managed frequency. In future, loads may be required to do more than just be able to be switched off during severe under frequency events. This thesis focuses on the development and practical implementation of the control structure of a smart adaptive load for network power-frequency support applications. The control structure developed makes use of advanced demand side management of fan loads (powered by AC drives) used in heating, ventilation, and air conditioning systems; where a change in power at rated load has little effect on their speed due to the cubic relationship between speed and power. The AC drive implemented in this thesis is based on an induction motor and a two level voltage source converter. To achieve the smart adaptive load functionality, first a power-frequency multi-slope droop control structure (feedforward control) is developed; relating the frequency limits imposed by the network supplier and the fan power-speed profile (Chapter 2, Fig 2.19). Secondly, this control structure is combined with the control developed, in Chapter 3, for the AC drive powering the fan load. The full development of the control structure of the AC drive, its tuning process and its practical implementation is given; an equation is developed to find suitable tuning parameters for the speed control of the nonlinear load (fan load), i.e. Eq. (3.59).The analysis and simulation results provided in Chapter 4 conclude that a fast control of the active power drawn by the AC drive is possible by controlling the electromagnetic torque (hence current) of the induction motor without disturbing the fan load overly. To achieve this, changes between closed loop speed control and open loop torque control (power control) are performed when needed. Two main issues were addressed before the hardware implementation of the smart adaptive load: the estimation of the network frequency under distorted voltage conditions, and the recovery period of the network frequency. In this thesis two slew rate limiters were implemented to deal with such situations. Other possible solutions are also outlined. Finally, experimental results in Chapter 5 support results given in Chapter 4. A full power-frequency response is achieved by the smart adaptive load within 3s.

Les directives européennes visant à produire 20% de l’énergie à base de sources renouvelables imposent aux gouvernements d’investir dans de nouveaux moyens de production. Un bilan du marché de l’énergie sera réalisé et permettra de montrer la part des énergies renouvelables dans la consommation d’énergie. Après les moyens de conversion de l’énergie hydraulique, les éoliennes sont les systèmes, utilisant une source renouvelable, les plus rencontrées. Les objectifs fixés ont conduit à s’intéresser à l’installation d’éoliennes en mer. Les contraintes spécifiques rencontrées ont poussé les acteurs du marché à développer de nouveaux systèmes et donc des alternateurs adaptés : utilisation des aimants permanents et de l’attaque directe. La modélisation des machines à aimants permanents est décrite. Une topologie classique est d’abord présentée. D’autres solutions seront ensuite étudiées dans le but d’augmenter les densités de couple. L’une d’elles est la machine à bobinage à pas fractionnaire qui permet d’éviter les enchevêtrements des têtes de bobines. D’autre part, l’utilisation de systèmes polyphasés, permettant d’augmenter la disponibilité des systèmes en autorisant des fonctionnements en modes dégradés, est un moyen intéressant afin d’être en présence de systèmes plus fiables. La démarche, qui a permis d’effectuer le choix du dimensionnement de la génératrice pour répondre au mieux à l’appel d’offre d’un client, est présentée ainsi que les résultats des essais réalisés sur les prototypes. Au final, l’éolienne qui est équipée de cet alternateur a une puissance massique qui est au moins 15% plus importante que les solutions disponibles en 2013 sur le marché. / Given the European guidelines, which consist into producing 20% of the energy from renewable sources, the governments are obliged to invest in new types of production systems. An energy market survey will show the part of renewable energy in the energy consumption. After the hydroelectric systems, the wind turbines are the most common systems using renewable sources. The current objectives have led to consider the installation of offshore wind turbine. The specific limitations led the market players to develop new systems with adapted generators: direct drive permanent magnet generator. Model of the permanent magnet machines is described. First a conventional machine topology is presented, then other solutions will be studied with the objective of increasing the torque density. One of them is the concentrated winding machines where the end winding overlapping is avoided. On the other hand, use multiphase system becomes very interesting in order to increase system reliability and work in fault tolerant modes. The strategy that was adopted for the design of the generator to fit the best the specification is also discussed as well as the results of the tests. At the end, the wind turbine equipped with this alternator, has a power density at least 15% higher than the 2013’s available solutions.

Energiflöden i fläkt och fläktkoppling har undersökts för att öka förståelsen om hur fläktvarvtalet varierar med fordonshastigheten. Problemet har studerats på en lastbil vid olika fordonshastigheter och fläktvarvtal. Undersökningen har genomförts genom att studera olika förluster, geometri på fläktblad, data från tidigare prover och genom CFD-simulering. De förlusterna som undersökts är lagerförluster och viskoförluster. Utifrån den befintliga geometrin på fläkten och från simulering har inloppshastigheterna mot fläkten jämförts. Simuleringarna är gjorda på en befintlig provbil där fläkten är simulerad med hjälp av MRF-modellering. Studien visar att fläktkopplingsmodell, fläkttyp och fläktens diameter inte är av så stor betydelse för att förklara problemet, däremot kan det ses att bilens modul är av vikt. Detta tros vara av vikt på grund av vad modulen får för tryckuppbyggnad. Luftens hastighet in mot fläkten kan vara en parameter som är av betydelse utifrån analys av tidigare provning och från simulering. Utifrån det kan det funderas på om fläkten bör dimensioneras om, att den bör dimensioneras efter låga fläktvarvtal istället för höga. Detta på grund av att fläkten endast är aktiv, och då har höga varvtal, cirka X % av bilens drifttid för typisk långtradartrafik, det vill säga inte så lång tid av bilens drifttid. Resultatet från den här undersökningen bör ses som en vägvisare hur man ska gå vidare för att förklara problemet och om man utifrån det kan minska bränsleförbrukningen. / Energy flows in fan and fan-clutch has been investigated to increase the understanding of how fan speed varies with the vehicle speed. The problem has been studied on a truck at different vehicle speeds and fan speeds. The thesis has been conducted by studying various losses, the fan geometry, data from previous tests and by CFD-simulation. The losses noted are bearing losses and visco losses. Based on the existing fan geometry and from simulation, the inlet velocities against the fan has been compared. The simulation are made from an existing test vehicle where the fan is simulated using MRF modeling. The study shows that the model of the fan clutch, the fan type and fan diameter are not so important to explain the problem, however, it can be seen that the truck’s module is of importance. This is thought to be important because of the modules pressure build-up. It can also be seen that the air velocity towards the fan can be a parameter that is important based on analysis of previous testing and from simulation. However, on this basis we should be reconsidering if the fan should be dimensioned the way it is today, at high fan speeds, or if it should be dimensioned at low fan speeds. This because the fan is only active, and then has high speeds, about X % of the car’s operating time for a typical long haulage truck, i.e. not that long of the truck’s operating time. The result of this study should be interpreted as a guide on how to proceed to explain the problem and if it can be used to reduce the fuel consumption.

No description available.

Multilevel voltage source inverters have been receiving more and more attention from the industry and academia as a choice for high voltage and high power applications. The high voltage multilevel inverters can be constructed with existing low voltage semiconductor switches, which already have a mature technology for handling low voltages, thus improving the reliability of the overall inverter system. These multilevel inverters generate the output voltage in the form of multi-stepped waveform with smaller amplitude. This will result in less dv/dt at the motor inputs and electromagnetic interference (EMI) caused by switching is considerably less. Because of the multi-stepped waveform, the instantaneous error in the output voltage will be always less compared to the conventional two-level inverter output voltage. It will reduce the unwanted harmonic content in the output voltage, which will enable to switch the inverter at lower frequencies. Many interesting multi level inverter topologies are proposed by various research groups across the world from industry and academic institutions. But apart from the conventional 3-level NPC and H-bridge topology, others are not yet highly preferred for general high power drives applications. In this respect, two different five-level inverter topologies and one three-level inverter topology for high power induction motor drive applications are proposed in this work. Existing knowledge from published literature shows that, the three-level voltage space vector diagram can be generated for an open-end winding induction motor by feeding the motor phase windings with two two-level inverters from both sides. In such a configuration, each inverter is capable of assuming 8 switching states independent of the other. Therefore a total of 64 switching combinations are possible, whereas the conventional NPC inverter have 27 possible switching combinations. The main drawback for this configuration is that, it requires a harmonic filter or isolated voltage source to suppress the common mode currents through the motor phase winding. In general, the harmonic filters are not desirable because, it is expensive and bulky in nature. Some topologies have been presented, in the past, to suppress the common mode voltage on the motor phase windings when the both inverters are fed with a single voltage source. But these schemes under utilize the dc-link voltage or use the extra power circuit. The scheme presented in chapter-3 eliminates the requirement of harmonic filter or isolated voltage source to block the common mode current in the motor phase windings. Both the two-level inverters, in this scheme, are fed with the same voltage source with a magnitude of Vdc/2 where Vdc is the voltage magnitude requires for the NPC three-level inverter. In this scheme, the identical voltage profile winding coils (pole pair winding coils), in the four pole induction motor, are disconnected electrically and reconnected in two star groups. The isolated neutrals, provided by the two star groups, will not allow the triplen currents to flow in the motor phase windings. To apply identical fundamental voltage on disconnected pole pair winding, decoupled space vector PWM is used. This PWM technique eliminates the first center band harmonics thereby it will allow the inverters to operate at lower switching frequency. This scheme doesn’t require any additional power circuit to block the triplen currents and also it will not underutilize the dc-bus voltage. A five-level inverter topology for four pole induction motor is presented in chapter-3. In this topology, the disconnected pole pair winding coils are effectively utilized to generate a five-level voltage space vector diagram for a four pole induction motor. The disconnected pole pair winding coils are fed from both sides with conventional two-level inverters. Thereby the problems like capacitor voltage balancing issues are completely eliminated. Three isolated voltage sources, with a voltage magnitude of Vdc/4, are used to block the triplen current in the motor phase windings. This scheme is also capable of generating 61 space vector locations similar to conventional NPC five-level inverter. However, this scheme has 1000 switching combinations to realize 61 space vector locations whereas the NPC five-level inverter has 125 switching combinations. In case of any switch failure, using the switching state redundancy, the proposed topology can be operated as a three-level inverter in lower modulation index. But this topology requires six additional bi-directional switches with a maximum voltage blocking capacity of Vdc/8. However, it doesn’t require any complicated control algorithm to generate the gating pulses for bidirectional switches. The above presented two schemes don’t require any special design modification for the induction machine. Although the schemes are presented for four pole induction motor, this technique can be easily extend to the induction motor with more than four poles and thereby the number of voltage levels on the phase winding can be further increased. An alternate five-level inverter topology for an open-end winding induction motor is presented in chapter-4. This topology doesn’t require to disconnect the pole pair winding coils like in the previous propositions. The open-end winding induction motor is fed from one end with a two-level inverter in series with a capacitor fed H-bridge cell, while the other end is connected to a conventional two-level inverter to get a five voltage levels on the motor phase windings. This scheme is also capable of generating a voltage space vector diagram identical to that of a conventional five-level inverter. A total of 2744 switching combinations are possible to generate the 61 space vector locations. With such huge number switching state redundancies, it is possible to balance the H-bridge capacitor voltage for full modulation range. In addition to that, the proposed topology eliminates eighteen clamping diode having different voltage ratings compared to the NPC inverter. The proposed topology can be operated as a three-level inverter for full modulation range, in case of any switch failure in the capacitor fed H-bridge cell. All the proposed topologies are experimentally verified on a 5 h.p. four pole induction motor using V/f control. The PWM signals for the inverters are generated using the TMS320F2812 and GAL22V10B/SPARTAN XC3S200 FPGA platforms. Though the proposed inverter topologies are suggested for high-voltage and high-power industrial IM drive applications, due to laboratory constraints the experimental results are taken on the 5h.p prototypes. But all the proposed schemes are general in nature and can be easily implemented for high-voltage high-power drive applications with appropriate device ratings.

No description available.

No description available.