Modeling And Simulation Of The Switched Reluctance Motor

This Paper summarizes the study conducted on the techniques used and implemented to minimize the torque ripple of the Switched reluctance Motors. These motors although offering the advantages of higher speeds, reliability and phase independence, have the limitations of the torque ripple and non-linearity in the magnetic characteristics. Thus in order to have the good understanding of the Motor, it is simulated in the MATLAB/SIMULINK environment. This paper describes details on modeling of two different configurations of Switched Reluctance Motor concentrating only on the linear model by obeying all of its characteristics. The two configurations of motors are applied with two different control techniques and the results are calculated and tabulated. Load and No load analysis are also performed to understand the behavior of motor with load. Through out the analysis, various values of turn-on and turn-off angles are selected and finally the optimum values are calculated based on the performance parameters of Average torque, speed and torque ripple. All simulations are documented through this paper including its block models and initializations performed. Finally a control technique is recommended which produces the best results with smallest torque ripple

Dynamic analysis of fast-acting solenoid actuators

There has been a recent revival of interest in the design of fast-acting solenoid actuators. This is due to the emergence of new control applications in the automotive industry constrained by tighter emission and noise regulations. In the context of developing a rapid computer-aided design tool for such applications, the thesis proposes several methods for computing the static and dynamic electromagnetic performance of solenoid actuators with a particular attention given to two actuator types : an axisymmetric and a rectangular solenoid actuator with a flat-faced armature. The magnetostatic performance of both actuator types is first evaluated by developing a detailed magnetic equivalent circuit in which the actuator geometry, saturation and end-effects are all taken into account. A comparison of the analytical model, based on the computation of the magnetisation characteristics and static forces for several airgap lengths, is given with finite-elements and measurements. In order to increase the computational speed of the static performance, the concept of magnetic gauge curve is presented. It is shown that this approach is in principle valid for any type of variable reluctance machine. Although the complexity of the gauge curve expression varies significantly from one device to another, it is shown that this method is an efficient way to store the magnetic data for a rapid computer aided-design or a real time application. When applied to the two previous types of solenoid actuator, it also leads to a very fast and accurate static force computation. The dynamic performance of the solid iron actuators requires the evaluation of the magnetic damping due to eddy currents. Based on a ID model of the flux and eddy current diffusion within an iron bar, an electromagnetic equivalent circuit of the axisymmetric is derived, in which the material nonlinearity, armature movement and eddy currents, a function of the previous parameters, actuator geometry and driving conditions, are modelled. A dynamic model of the partly solid iron rectangular actuator is also proposed and evaluated. In both cases a comparison of the transient current and force waveforms with 2D or 3D finite elements and measurements is given under various driving conditions

Development of methods, algorithms and software for optimal design of switched reluctance drives

The aim of this thesis is to estimate the perspectives of integrated switched reluctance drives (I-SRDs), i.e. reluctance machines integrated with converters. It is assumed that such drive series can be manufactured in the power range of 0.75...7.5 kW and speed ranges of 300...3000 rpm and 600...6000 rpm for applications like pumps, fans, conveyors, compressors, extruders and mixers. Based on the performed research and design work it is stated that the new drives have to be developed according to their applications, which determine objective functions and constraints, and that the best possible design should be found as a solution of a synthesis task. Sizing equations are not applied at all. The approach used in the thesis is based on the virtual prototyping concept, i.e. the new I-SRD series is designed in a virtual environment. Therefore, mathematical models and the ways to verify them have to be elaborated. The concepts of multidisciplinary and multilevel modeling are applied. The multidisciplinary model is a combination of interconnected electromagnetic, thermal and noise models. The multilevel concept is the approach when different elements of the drive are described using different languages, i.e. on different levels. Several original solutions are introduced, like the electromagnetic model comprising SIMULINK block-diagrams and MATLAB script, expressions for the correction of the flux linkage due to end-effects, an original equivalent circuit for thermal analysis, which allows using a very simple and fast method to solve the circuit, together with the concept of a multi-layer equivalent cylinder for modeling the motor winding. For verification of the multidisciplinary model a database of test results has been collected using both testing of several reluctance machines in the laboratory and analyzing of test results published by other researchers. After verification the model can be considered as a virtual prototype and can be used in the synthesis process. Several methods of solving the synthesis task were tested. The method, proved to be best suited for solving this task in the proposed form, is the genetic algorithm in the vector form with alphabetic encoding. The genetic algorithm should be coupled with the experimental design method or with the Monte-Carlo method

Aspects of magnetisation and iron loss characteristics in switched-reluctance and permanent-magnet machines

In the first section, the magnetisation characteristics of the switched-reluctance motor are examined. Measurements have been carried out using both static and dynamic test methods. The test data has been compared with simulation results from analytical design programs and finite element models. The effects of mutual coupling on the magnetisation characteristics are investigated through measurement and simulation. Results show that the degree of mutual coupling is strongly dependent on the winding arrangement of the machine. In the next section, the difficulties in measuring the properties of permanent-magnet machines are discussed in detail, and solutions to common problems proposed. The measurement and analysis methods used for the switched-reluctance motor are further developed for analysis of permanent magnet machines. Techniques for determining the variation in synchronous reactances and permanent magnet flux are presented. Finite element simulations are used to show the variation of magnet flux under loading, a condition ignored in classical analysis methods. The final section discusses the analysis of magnetisation characteristics of electrical sheet steels. Comparison is made between measurements carried out on single sheet tester and Epstein square test rigs. The iron losses of a typical non-grain-orientated steel are measured under both sinusoidal and nonsinusoidal flux density conditions. The iron losses are shown to increase significantly when higher harmonic components are introduced to the flux density waveform. The difficulties in modelling the nonlinear iron loss characteristics of electrical steels are considered

Finite element analysis of switched reluctance motor with rotor position based control

This research presents a field-circuit coupled parallel finite element model of a switched reluctance motor embedded in a simple closed loop control system. The parallel numerical model is based on the Schur-complement method coupled with an iterative solver. The used control system is the rotor position based control, which is applied to the FEM model. The results and parallel performance of the voltage driven finite element model are compared with the results from the current driven model. Moreover, the results of the start-up of the loaded motor show why the model accuracy is important in the control loop

Modeling And Simulation Of The Switched Reluctance Motor

This Paper summarizes the study conducted on the techniques used and implemented to minimize the torque ripple of the Switched reluctance Motors. These motors although offering the advantages of higher speeds, reliability and phase independence, have the limitations of the torque ripple and non-linearity in the magnetic characteristics. Thus in order to have the good understanding of the Motor, it is simulated in the MATLAB/SIMULINK environment. This paper describes details on modeling of two different configurations of Switched Reluctance Motor concentrating only on the linear model by obeying all of its characteristics. The two configurations of motors are applied with two different control techniques and the results are calculated and tabulated. Load and No load analysis are also performed to understand the behavior of motor with load. Through out the analysis, various values of turn-on and turn-off angles are selected and finally the optimum values are calculated based on the performance parameters of Average torque, speed and torque ripple. All simulations are documented through this paper including its block models and initializations performed. Finally a control technique is recommended which produces the best results with smallest torque ripple

Coupled electromagnetic and thermal analysis of electric machines

Mestrado de dupla diplomação com a UTFPR - Universidade Tecnológica Federal do ParanáThe actual trend of the design process of electric machines is oriented to specific requirements of the application and is no longer based in a standard structure. From this point of view, the design procedure of electric machines became a multidisciplinary process, involving electromagnetic, thermal, and mechanical modelling in a highly iterative process between the different physics fields. This dissertation deals with the design process of electric machines, proposing a coupling methodology for the electromagnetic and thermal models which are interrelated. The electromagnetic model establishes the main losses in electric machines: iron and resistive losses. These losses are, in turn, the main heat sources, responsible for heating and temperature distribution, i.e., the object of the thermal analysis, which affects recursively the losses, due to parameter’ dependency on temperature. Also, the machine temperature is crucial to maintain the lifetime of the machine. So, the coupled analysis is mandatory to achieve the nowadays requirements of higher energy efficiency and power density and cost reduction. Also, the coupled analysis enables optimization without the need to build several prototypes, making this process more time and cost-efficiency. Despite the temperature importance in electric machines, the thermal model was overlooked over the years. However, it has been receiving more attention in the past years. In this work, the thermal modelling process is handled analytically and numerically through finite element analysis (FEA), which is also used to obtain the electromagnetic model. The modelling processes detailed during this work are applied into a case study of a single-phase transformer with the rated power of 1 kW. The numerical models were developed in the Ansys software suite, being the electromagnetic model developed in Ansys Maxwell while the thermal model has developed in Ansys Mechanical. At last, the coupling between the electromagnetic and thermal models was accomplished in Ansys Workbench. The results obtained from the models are compared and validated with the experimental measurements of the losses and temperatures.A tendência atual do processo de projeto de máquinas elétricas é orientada para requisitos específicos de sua aplicação e não é mais baseada em uma estrutura padrão. Deste ponto de vista, o procedimento de projeto de máquinas elétricas tornou-se um processo multidisciplinar, envolvendo modelagem eletromagnética, térmica e mecânica em um processo altamente iterativo entre os diferentes campos da física. Esta dissertação trata do processo de projeto de máquinas elétricas, propondo uma metodologia de acoplamento dos modelos eletromagnético e térmico que se inter-relacionam. O modelo eletromagnético estabelece as principais perdas em máquinas elétricas: perdas de ferro e resistivas. Essas perdas são, por sua vez, as principais fontes de calor, responsáveis pelo aquecimento e distribuição de temperatura, ou seja, o objeto da análise térmica, que afeta recursivamente as perdas, pois os parâmetros são dependentes da temperatura. Além disso, a temperatura da máquina é crucial para manter a vida útil da máquina. Assim, a análise acoplada é obrigatória para atender aos requisitos atuais de maior eficiência energética e densidade de potência e redução de custos.Além disso, a análise acoplada possibilita a otimização sem a necessidade de construção de vários protótipos, tornando este processo mais eficiente em termos de tempo e custos. Apesar da importância da temperatura nas máquinas elétricas, o modelo térmico foi negligenciado ao longo dos anos. No entanto, tem recebido mais atenção nos últimos anos. Neste trabalho, o processo de modelagem térmica é tratado analiticamente e numericamente por meio da análise de elementos finitos (FEA), que também é utilizada para obter o modelo eletromagnético. Os processos de modelagem detalhados durante este trabalho são aplicados em um estudo de caso de um transformador monofásico com potência nominal de 1 kW. Os modelos numéricos foram desenvolvidos no pacote de software Ansys, sendo o modelo eletromagnético desenvolvido no Ansys Maxwell enquanto o modelo térmico foi desenvolvido no Ansys Mechanical. Por fim, o acoplamento entre os modelos eletromagnético e térmico foi realizado no Ansys Workbench. Os resultados obtidos com os modelos são comparados e validados com as medições experimentais das perdas e temperaturas

Aktiivinen magneettilaakeri vaihtoreluktanssimoottorina

The goal of this work was to research the similarities between active magnetic bearings and switched reluctance motor and particularly research the chances for converting magnetic bearing into switched reluctance motor. In addition, ways to cope with the widely reported problems the motor type has were studied. The test environment consisted of test rig, previously used for testing control methods for magnetic bearing. In addition to this, MATLAB Simulink simulation models were built to help the designing of the test setup. The test setup had two alternative controllers, an original magnetic bearing controller, modified to work as a motor controller and a new CompactRIO-based controller that was used for comparing different speed control and commutation methods. New rotor designs were engineered to work with the prototype motor that used unmodified magnetic bearing stator. This setup was tested for obtaining the output torque and maximum speed of the motor together with the accuracy to follow set values. Test results of simulations and test setup were inside the error margins, showing the use of simulations beneficial in design process of this type of a motor. The tests revealed differences between the control methods, suggesting using the advanced angle controller and adjustable commutation angles.Työn tavoitteena oli tutkia yhteneväisyyksiä aktiivimagneettilaakerien ja vaihtoreluktanssimoottorin välillä. Tutkimus keskittyi erityisesti arvioimaan mahdollisuuksia muuntaa magneettilaakeri vaihtoreluktanssimoottoriksi. Lisäksi tutkittiin keinoja ratkaista ongelmia, joita tämän tyyppisessä sähkömoottorissa on raportoitu olevan. Testiympäristö koostui roottorikoelaitteesta, jota on aikaisemmin käytetty magneettilaakerin säätöjärjestelmän tutkimuksessa. Lisäksi rakennettiin MATLAB Simulink simulointimalli, jota käytettiin moottorin säätöjärjestelmän suunnittelun apuna. Testilaitteessa oli kaksi vaihtoehtoista säätöjärjestelmää; alkuperäinen magneettilaakerin ohjain muokattuna toimimaan moottorin ohjaimena sekä uusi CompactRIO -järjestelmään perustuva säätöjärjestelmä. Jälkimmäistä käytettiin erilaisten nopeus- ja kommutointitapojen vertailuun keskenään. Prototyyppimoottorin staattori oli sama, jota käytettiin magneettilaakerin kanssa. Roottori suunniteltiin sopimaan juuri tähän käyttötarkoitukseen. Tätä koelaitetta testattiin vääntömomentin ja maksiminopeuden selvittämiseksi. Lisäksi suoritettiin testejä, joissa tutkittiin kykyä seurata nopeuden asetusarvoa. Simuloimalla saadut tulokset olivat hyvin lähellä koelaitteella saatuja tuloksia osoittaen simuloinnin käytön olevan hyödyllistä tämän tyyppisen moottorin suunnittelussa. Säätömenetelmät suoriutuivat vaihtelevalla menestyksellä testeistä. Suositeltava säätömenetelmä oli edistyskulman säädin, joka käytti hyväkseen säädettäviä kommutointikulmia

Position estimation and performance prediction for permanent-magnet motor drives

PhD ThesisThis thesis presents a theoretical and experimental development of a novel position estimator, a simulation model, and an analytical solution for brushless PM motor drive. The operation of the drive, the position estimation model of the test motor, development of hardware, and basic operation of inverter are discussed. Starting with the well-known continuous-time model of brushless PM motor, a sampled-data model is developed that is suitable for th6, application of real-time position estimator. An analytical methodo f calculating the steady-stateb ehaviouro f the brushlessP M motor for 1200in verter operation is presentedT. he analysisa ssumesth at the machinea ir gap is free of saliency effects, and has sinusoidal back EMF. The analytical solution is derived for 60" electrical of the whole period. By experimental results, it is shown that the method of analysis is adequate to predict Ihe motor's performance for typical operating points including phase advance and phase delay operation. C) I A computer simulation model for prediction of the performance of brushless PM moto rs is presented. The model is formulated entirely in the natural abc frame of reference, which allows direct comparison of the simulation and corresponding experimental results. The equations and diagrams are put into a convenient form for the simulation and future developments and library modules. The simulation model and corresponding experimental data of the brushless PM motor drive is given. The thesis describes a modem solution to real-time rotor position estimation, which has been subject to intense research activity for the last 15 years. The implemented new algorithm for shaft position sensorless operation of PM motors is based on the flux linkage and line current estimation. The position estimation algorithm has also been verified by both off-line and on-line experiments (accomplished by a DSP, TMS320C30), and a wide range of steady-statea nd transient results have been 0gi0v en including starting from rest. The position estimation method effectively moves the position measurement point in the drive from the mechanical side to the motor's terminals. As well as eliminating the mechanical shaft position sensor, the investigated method can be used for high performance torque control of brushless PM motors. The thesis demonstrates that, in contrast to many other "sensorless" schemes, the new position estimation method is able to work effectively over the full operating range of the drive, and is applicable to a wide range of motor/converter types. Since the hardware is straightforward, only the new position estimation algorithm differentiates a system. Therefore, if a DSP control system is already implemented in the drive, the position estimator can be implemented at low cost.Istanbul Technical University and Higher Education Counci