The thesis deals with the problematics of short-circuit current of synchronous machine. The first section focuses on the theoretical process of short-circuit current of synchronous machine and describes how this transient process changes throughout it's duration and with what reactances and time constants it is defined. Subsequently, this section deals with the methodics of tests of the snychronous machine,which may be used to set it's reactances. The second part of the work focuses on measurement of the short-circuit current in a specific synchronous machine. Further, there are measurements of processes of the short-circuit in time and their analysis. The last section of the thesis deals with the simulation of short-circuit current process. The simulation is ran by the Matlab/Simulink software. Simulated processes of short-circuit are then compared with the results of measurements from the previous section of the thesis.

Algorithms of sensorless control of surface permanent magnet synchronous motors are discussed in the dissertation thesis. A method for position and speed estimation in high-speed region based on model reference adaptive system is described. Furthermore, classical approach using Kalman filtering was verified. Kalman filter expected the rotor speed to be constant as a modification of model using variable speed approach. These algorithms are not able to work at low speed region, thus a new method was proposed. This method is designed on extended Kalman filtering and uses the model which describes the stator inductance changes in - coordinates. At motor start, knowledge of initial rotor setup is required. The algorithm for initial rotor angle using high frequencies injected into the motor was proposed.

Master’s thesis summs up issues of mounting pemanent magnets on rotor surface of permanent magnet synchronous machine. Literature reseach is divided in two parts. First one shows studies and experiments researching the impact of manufacturing tolerances of permanent magnets and wrong mounting on the rotor on cogging torque . The second part focus on analytical aproach of defining influence of permanent magnets on magnetic flux density in the air gap and phase induced voltage. Practical part focus on design of a prototype machine, wich will be used to research the impact of tolerances and imperfections. Parametric model of the prototype machine is created in Maxwell and is subjected to analysis via finite element method. Three different analysis were run, offset of permanent magnet, decrease and wrong dicertion of magnetization. At last the result of cogging torque and induced voltage are compared.

Ce travail de thèse a pour objectifs l'observation et la commande des convertisseurs multi-niveaux et la commande des machines synchrones. Pour satisfaire le besoin des clients de l’entreprise GS Maintenance et pour des raisons de maintenance, une commande en courant de la machine synchrone est implémentée expérimentalement. L'accent est mis sur le démarrage de ce type de machines car durant ces phases de fonctionnement (basses vitesses), les forces électromotrices sont faibles pour assurer la commutation des thyristors de l'onduleur. Ensuite, l'entreprise a proposé à ses clients un convertisseur statique en moyenne tension afin de garder sa place dans la variation de vitesse. Dans ce cadre, une commande en tension moderne de la machine synchrone alimentée par un onduleur de tension est proposée et validée par des résultats de simulation. Compte tenu du fonctionnement en moyenne tension, les convertisseurs multi-niveaux ont été retenus par l’entreprise. Dans ce cadre, le convertisseur multicellulaire série est proposé dans ce travail et une commande directe basée sur la théorie des modes glissants et le principe de priorité est conçue pour assurer l'équilibrage des tensions flottantes du convertisseur. Cette commande a été généralisée pour un nombre quelconque de cellules du convertisseur et validée par des résultats de simulation pour un nombre de cellules égal à 7. Pour réduire le coût et l'encombrement du convertisseur, un observateur adaptatif des tensions flottantes est proposé en prenant en compte les états de commutation du convertisseur. Cet observateur est ensuite associé à la commande directe en boucle fermée. Un banc d'essai du convertisseur à 3 cellules est réalisé au sein de l’entreprise et l’ensemble « observateur + commande directe » est testé expérimentalement sur ce banc. / This PhD thesis aims to the observation and control of multilevel converters and the synchronous machines control. To satisfy the needs of GS Maintenance's customers and for maintenance reasons, a control strategy for a current fed self controlled synchronous machine is validated by experiments tests. The proposed strategy focus on a very low speed because the machine counter electromotive force is insufficient for inverter thyristors switching. Recently, the company proposed for its customers a power converter with medium voltage to keep its place in the speed variation. So, a modern voltage control of the synchronous machine fed by a voltage inverter is proposed and validated by simulation results. Medium voltage operation encouraged the company to choose the multi-level converter. Then, the flying capacitor converter is proposed in this work and a direct control based on the sliding mode theory and the priority principle is designed to guarantee the voltage balance. This control strategy has been generalized for any number of cells of the converter and validated by simulation results for a 7 cells converter. To reduce the cost and complexity of the converter, an adaptive observer floating voltages is proposed by taking into account the switching states of the converter. This observer is then associated with the direct control in closed loop. A test bench of a 3 cells converter is set up in the company. Experimental tests of « observer based direct control » are then conducted on this test bench.

This thesis deals with the design of a permanent-magnet synchronous inner rotor motor for an in-wheel application for the Shell Eco Marathon Urban concept vehicle. First of all, concepts related to permanent magnet motors are studied. Likewise, different features of permanent magnet motors are qualitatively evaluated in order to choose the most suitable. A radial flux motor is selected based on its solid, economic and acceptable characteristics. Next, a detailed study of concentrated windings is carried out. Through this investigation, undesirable configurations of pole and slot numbers due to unbalanced magnetic pull or a low fundamental winding factor will be avoided and how to determine the different winding layouts for different pole and slots configuration will be explained. As well, based on this study, and the magnetic and electric behavior of the machine, an analytical model is created. This model calculates the optimum size and characteristics of a machine in order to obtain lightweight design. After that, the design of a program based on a finite element method that simulates different situations for the machine is accomplished, dealing with the difficulties that entails the concentrated windings. Finally, through the use of this program, the machine calculated by the analytical model is analyzed, specially regarding that it does not surpass some important margin in order not to be demagnetized or not to surpass the maximum phase voltage supplied by the batteries.

This thesis investigates simulation of synchronous machines using a novel Magnetic Equivalent Circuit (MEC) model. The proposed model offers sufficient detail richness for design calculations, while still keeping the simulation time acceptably short. Different modeling methods and circuit alternatives are considered. The selected approach is a combination of several previous methods added with some new features. A detailed description of the new model is given. The flux derivative is chosen as the magnetic flow variable which enables a description with standard circuit elements. The model is implemented in dq-coordinates to reduce complexity and simulation time. A new method to reflect winding harmonics is introduced. Extensive measurements have been made to estimate the traditional dq-model parameters. These in combination with analytical calculations are used to determine the parameters for the new MEC model. The model is implemented using the Dymola simulation program. The results are evaluated by comparison with measurements and FEM simulations. Three different operation cases are investigated; synchronous operation, asynchronous start and inverter fed operation. The agreement with measurements and FEM simulations varies, but it is believed that it can be improved by more work on the parameter determination. The overall conclusion is that the MEC method is a useful approach for detailed simulation of synchronous machines. It enables proper modeling of magnetic saturation, and promises sufficiently detailed results to enable accurate loss calculations. However, the experience is that the complexity of the circuits should be kept at a reasonable low level. It is believed that the practical problems with model structure, parameter determination and the simulation itself will otherwise be difficult to master.

The thesis presents deals with the design, analysis, test and control of permanent magnetsynchronous motor(PMSM). An analytical model was carried out based on the d-q frame and the equivalent circuit of PMSM, theanalytical model gives an approximation value of the machine parameters and is carried out byequations from the listed references. this phase includes many iteration steps, once the results wereobtained they were compared with the motor specifications and if they don’t match the requiredspecifications the process must be done again until the desired design is obtained. Once the analytical model is obtained a Finite Element Simulation was carried out using FEMMsoftware to validate the design, in this phase the designed machine in the analytical model isanalyzed and validated, once the simulation is done the results from both models are compared anddiscussed in the results chapter. It’s important to mark that during the design phase some design parameters were affected andlimited by some factors, for example, the air gap length has been magnified due to manufacturinglimits. The manufacturing process and the prototype building have been started once the optimal designwas selected, the manufacturing process was explained and a comparison study was made to selectthe best manufacturing process suitable and available for this thesis.

In this thesis, the basics of electromagnetic theory for wave-energy conversion are reviewed, some of the characteristics of the ocean wave are investigated, some of the power take-off (PTO) systems are introduced, and details about linear permanent magnetic machines, in particular, are discussed.  The thesis aims to model the novel linear transverse flux machine designed by Anders Hagnestål and to build hysteresis current controller for power factor correc- tion. Although this machine is expected to have high performance in terms of efficiency, it also exhibits a strong mutual interaction between the three phases of the machine. Thus, simplification of the actual model of the machine is im- posed to mitigate the complexity of the machine and facilitate the Simulink model. Four cases of the double band hysteresis control are studied. The cur- rents seem to be responding properly to the control scheme; however, software and hardware programming of a microprocessor would be preferable to ensurethe applicability of the control strategy in a real environment. / I detta examensarbete undersöks elektromagnetisk teori och havsvågors egenskaper. Några energiomvandlingssystem introduceras och permanentmagnetiserade maskiner diskuteras i detalj. Syftet med avhandlingen är att modelleraen ny linjär transversalflödesmaskin som är designad av Anders Hagnestål och att bygga en hysteresbaserad strömkontroll för denna. Även om maskinen förväntas prestera bra, uppvisar den också en stark ömsesidig magnetisk interaktion mellan de tre faserna. För att kunna hantera detta problem och därmed kunna genomföra simuleringar införs en förenklad elektromagnetisk modell av maskinen. En strömkontroller har implementerats i Simulink, där fyra fall av dubbelbandshystereskontroll studerats. Resultaten från simuleringarna visar att strömkontrollern fungerar. Nästa steg i projektet är att utföra mjukvaru och hårdvaruprogrammering av en mikrokontroller för att testa systemet i enverklig miljö.

In this research, an attempt is made to evaluate alternative model-predictive microgrid control approaches and to understand the trade-offs that emerge between model complexity and the ability to achieve real-time optimized system performance. Three alternative controllers are considered and their computational and optimization performance compared. In the first, nonlinearities of the generators are included within the optimization. Subsequently, an approach is considered wherein alternative (non-traditional) states and inputs of generators are used which enables one to leverage linear models with the model predictive control (MPC). Nonlinearities are represented outside the control in maps between MPC inputs and the physical inputs. Third, a recently proposed linearized trajectory (LTMPC) is considered. Finally, the performance of the controllers is examined utilizing alternative models of the synchronous machine that have been proposed for power system analysis.

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