This thesis focuses on modelling of the permanent magnet synchronous reluctancemotor (PMSynRM), which has drawn considerable attention by researchers thanks toits high efficiency and wide range of speed operation. Comparisons with measurementsfrom a four-pole PMSynRM with four barriers and 24 stator slots have been carriedout. In this thesis work, Matlab and Comsol Multiphysics are used to implement theparameterized PMSynRM model.Models of the PMSynRM in two-dimensions (2D) and three-dimensions (3D) havebeen implemented. The electromotive force (back emf) at no load condition for a fullpitchand short-pitch winding as well as the air-gap flux density distribution have beencalculated. A parametric study has been performed where the air-gap length, insulationratio of both d and q-axes, as well as flux barrier number have been varied and theeffect on the machine performance has been observed. The losses including eddycurrentlosses in permanent magnet, stator lamination loss, and rotor lamination losshave been calculated. The back emf and rated torque as well as developed torque witha pure q-axis current have been compared with corresponding experimental data.A 3D model of an axially shortened rotor has also been implemented in where apulsating current has been applied to estimate eddy-current losses in the permanentmagnets. The predicted losses from the 2D model and 3D model have been comparedfor pulsating currents with varying frequency and magnitude. / Denna avhandling fokuserar på modellering av permanentmagneten synkronreluktansmotor (PMSynRM), som har fäst stor uppmärksamhet av forskare tack varedess höga effektivitet och brett spektrum av hastigheter. Jämförelser med mätningarfrån en fyrpolig PMSynRM med fyra hinder och 24 statorspåren har utförts. I dettaexamensarbete, Matlab och Comsol Multi används för att implementera parameterPMSynRM modell. Modeller av PMSynRM i två dimensioner (2D) och tre dimensioner(3D) har genomförts. Den elektromotoriska kraften (mot-emk) utanbelastningstillstånd för en full-pitch och kort stigning lind samt luftgapetfördelningsflödestäthet har beräknats. En parametrisk studie har gjorts där luftspaltlängden,isolering förhållande av både d- och q-axlar, såväl somflödesbarriärnummer har varierats och effekten på maskinens prestanda harobserverats. Förlusterna inklusive virvelströmsförluster i permanentmagnet,statorskiktet förlust, och rotorlamine förlust har beräknats. Mot-emk och nominelltvridmoment samt utvecklat vridmoment med en ren q-axelström har jämförts medmotsvarande experimentella data. En 3D-modell av en axiellt förkortad rötor har ocksågenomförts i där en pulserande ström har tillämpats för att uppskattavirvelströmsförluster i permanentmagneterna. De förutsagda förluster från 2Dmodellenoch 3D-modell har jämförts för pulserande strömmar med varierandefrekvens och storlek.

Geomagnetic disturbances that result from solar activities can affect technological systems such as power networks. They may cause DC currents in power networks and saturation of the core in power transformers that leads to destruction in the transformer performance. This phenomena result in unwanted influences on power transformers and the power system. Very asymmetric magnetization current, increasing losses and creation of hot spots in the core, in the windings, and the metallic structural parts are adverse effects that occur in transformers. Also, increasing demand of reactive power and malfunction of protective relays menaces the power network stability. Damages in large power transformers and blackouts in networks have occurred due to this phenomenon. Hence, studies regarding this subject have taken the attention of researchers during the last decades. However, a gap of a comprehensive analysis still remains. Thus, the main aim of this project is to reach to a deep understanding of the phenomena and to come up with a solution for a decrease of the undesired effects of GIC. Achieving this goal requires an improvement of the electromagnetic models of transformers which include a hysteresis model, numerical techniques, and transient analysis. In this project, a new algorithm for digital measurement of the magnetic materials is developed and implemented. It enhances the abilities of accurate measurements and an improved hysteresis model has been worked out. Also, a novel differential scalar hysteresis model is suggested that easily can be implemented in numerical methods. Two and three dimensional finite element models of various core types of power transformers are created to study the effect of DC magnetization on transformers. In order to enhance the numerical tools for analysis of low frequency transients related to power transformers and the network, a novel topological based time step transformer model has been outlined. The model can employ a detailed magnetic circuit and consider nonlinearity, hysteresis and eddy current effects of power transformers. Furthermore, the proposed model can be used in the design process of transformers and even extend other application such as analysis of electrical machines. The numerical and experimental studies in this project lead to understanding the mechanism that a geomantic disturbance affects power transformers and networks. The revealed results conclude with proposals for mitigation strategies against these phenomena. / <p>QC 20150210</p>