The reluctance torque of switched reluctance motor could drive the rotor directly. Rotor doesn¡¦t need to be made from permanent magnet and the demagnetization and heat emission problems can be avoided. There are also a lot of advantages, such as the low cost, high efficiency, high stability and high hot emission, make it very attractive to the engineers and researchers. The dual-flange-pole rotor structure will induce non-linear magnetic filed in the air gap between armature and rotor, so the reluctance torque is not easy to handle. The switched reluctance motor is considered hard to control at the early stages of development. In recently years, with the rapid improvement of power electronic devices and microprocessor chips, the engineers and researchers pay more attentions to overcome the difficulties encountered in both the software and hardware step by step. It can now exert the motor¡¦s capability to contend with the inductor motor and the alternating current motor. Furthermore, it is more advantageous than others in the high energy density, high temperature and adverse circumstances. It has obviously caught caused the industry¡¦s attention and the academia's research interests. The work of this is to design and develop a drive system for the switched reluctance motor drive system by using the 32-bit floating point Digital Signal Processor, and operate it in coordination with the peripheral circuits. Finally, the study will integrate the graph control programming to design a monitoring and control system with Man-Machinery Interface (MMI) for monitoring voltage, current and speed of the switched reluctance motor drive system.

­^¤å´£­n¡G The objective of this thesis is to simultaneously achieve two- dimensional control of transverse flux linear switched-reluctance machine (LSRM). Based on a theoretical matrix decomposition scheme, the overall structure of the control and drive systems can be constructed, and the associated man/machine interface can be designed. A fuzzy inference scheme has been selected to control the machine motion, while an orthogonal scheme has been developed to control the machine lift force. By realizing the control algorithm through digital signal processor (DSP), results show that the LSRM will be quite applicable for the desired operations of magnetic levitated vehicle.

The objective of this thesis is to present the algorithm of achieving speed and lift force controls of transverse flux linear switched-reluctance machine (LSRM) simultaneously. A high-speed digital signal processor based (DSP-based) switching controller will be implemented, and the desired speed control objective is realized by using a fuzzy control scheme. On the other hand, by using an indirect field-oriented control scheme, the LSRM reluctance forces, which are magnetically decoupled and position dependent, can be projected onto sets of stationary axes that are aligned with the motor fixed secondary poles. Hence by controlling flux on the specific stationary axis, the machine lift force can be properly controlled. Finally, adequate duty cycle distribution will be discussed and examined to asynchronously supply the required speed and lift force control objectives simultaneously.

This dissertation contains the results of research conducted on the design and control characterization of a Switched Reluctance Generator (SRG) for maximum output power. The SRG is an attractive solution to the increasing worldwide demand of electrical energy. It is low cost with a rugged structure, operates with high efficiency over a wide speed range, and is fault tolerant. In many applications, size and weight are the main criteria in selecting the generator. Hence, in design and control of the generator, system designers always strive for increasing power density, or in other words, maximizing the output power for a given size. Despite the extensive research on the motoring operation of the Switched Reluctance Machine, only a few publications have investigated the generating mode of operation of this machine. Results and algorithms from this research can be referenced for better utilizing the SRG in many applications. As the first stage to output power maximization, design parameters and control variables affecting the average output power of the SRG are identified through a systematic approach. The optimal values for maximizing the output power are found through an analytical approach and iterative simulations. The results are then verified experimentally. After finding the optimal values for control variables, a controller is designed. This controller is model dependent. If the model used for design is not accurate or the machine parameters are deviated from the designed values, the machine will not generate the maximum output power. Therefore, a self-tuning algorithm, based on a local search method, is proposed and experimentally tested. It works effectively and does not need extra hardware or rigorous calculations. The attempts to benefit from the SRG may look tantalizing, but it poses a challenge as well. Output power maximization can lead to an oversized SRG converter and its output filter, which will reduce the overall power density of the motor drive. The last piece of this dissertation analyzes the effect of a commutation algorithm on the output filter, reducing its size with active control of phase currents, and proposing a novel control algorithm that was investigated through experiments over all of the speed range.

The objective of this dissertation is to study the switched reluctance machine (SRM) electromagnetic design and optimization. The research of electric machines is mostly driven by the motivation for higher efficiency and lower cost. The demands for high-performance electric machines also come from the development of emerging industries, such as electric vehicles (EV), hybrid electric vehicles (HEV), renewable energy conversion, energy storage and precision manufacturing. The additional requirements for those applications include volume, weight, speed, torque, reliability, fault tolerance capability, etc. The focus of the research effort is on the high speed and high torque applications, where the SRM stands out compared to other types of machines. The conventional design method significantly depends on the designer’s experience, which uses equivalent magnetic circuit models, and therefore the SRM design is not well developed. A novel SRM electromagnetic design and optimization method is developed, which uses the current-fed FEA simulation as the SRM performance estimation tool. This method serves as the main innovation of this research work. First, the proposed method is applicable to any SRM topologies and dimension, and no detailed modeling of a specific SRM configuration is required in advance. Therefore, an automated SRM design and optimization approach is developed. Secondly, great accuracy of the SRM electromagnetic analysis, e.g. flux density, torque, and current calculation, is achieved by using FEA simulation instead of simplified magnetic circuit approximations. This contribution is particularly significant when considering the poor accuracy of conventional SRM analytical analysis methods, where several assumptions and approximations are used. Lastly, the proposed design method takes the typical SRM control strategy into account, where the excitation current profile is characterized as a trapezoid. This method adapts the flux linkage of the first FEA simulation result to specify the excitation current profile for the second FEA simulation, so the calculated SRM performance in FEA simulation agrees with the measurement on a practical machine. The proposed SRM design and optimization method is used for a 12/8 SRM rotor design and for a complete 4/2 SRM design. These design examples validate the applicability of the proposed method to different SRM configurations and dimensions. Detailed design steps are presented for both design cases, and the selection of the parametric design variables are also discussed. The optimization results are demonstrated using multi-dimension diagrams, where the optimal design with the highest torque can be easily identified. The FEA simulation results are compared to the experimental results of a fabricated SRM prototype, and good agreement is found. In addition, a new rotor configuration with a flux bridge is proposed for an ultra high speed SRM design. The primary motivation of this rotor topology is to reduce the windgae losses and the acoustic noise at a high speed of 50,000 rpm. However, care must be taken for the flux bridge design, and the impact of different flux bridge thicknesses to the SRM performance is studied. Meanwhile, the manufacturing difficulties and the mechanical stresses should also be considered when fabricating the flux-bridge rotor. As a result, two SRM prototypes are built, and the two rotors are one without a flux bridge and one with a flux bridge. The prototypes are tested at different speeds (10,000 rpm, 20,000 rpm and 50,000 rpm) respectively, and the experimental results show good agreement with the FEA simulation results.

This work is intended to contribute with knowledge to the area of electic motorsfor propulsion in the vehicle industry. This is done by first studying the differentelectric motors available, the motors suitable for vehicle propulsion are then dividedinto four different types to be studied separately. These four types are thedirect current, induction, permanent magnet and switched reluctance motors. Thedesign and construction are then studied to understand how the different typesdiffer from each other and which differences that are of importance when it comesto vehicle propulsion. Since the amount of available data about different electricmotors turned out to be small a tool was developed to use for collecting data fromthe sources available which can be for instance product sheets or articles with informationabout electric motors. This tool was then used to collect data that wasused to create models for the different motor types. The created motor models foreach motor type could then be used for simulating vehicles to investigate how thespecific motor is suited for different vehicles and applications. The work also containsa summary of different electric motor comparison studies which makes it agood source of information during motor type selection in the process of designingan electric vehicle.

The switched reluctance motor (SRM) is receiving attention because of its merits: high operating temperature capability, fault tolerance, inherent shoot-through preventing inverter topology, high power density, high speed operation, and small rotor inertia. Rotor position information plays a critical role in the control of the SRM. Conventionally, separate position sensors, are used to obtain this information. Position sensors add complexity and cost to the control system and reduce its reliability and flexibility. In order to overcome the drawbacks of position sensors, this dissertation proposed and investigated a position sensorless control system that meets the needs of an electric actuator application. It is capable of working from zero to high speeds. In the control system, two different control strategies are proposed, one for low speeds and one for high speeds. Each strategy utilizes a state observer to estimate rotor position and speed and is capable of 4 quadrant operation. In the low speed strategy a Luenberger observer, which has been named the inductance profile demodulator based observer, is used where a pulse voltage is applied to the SRMs idle phases generating triangle shaped phase currents. The amplitude of the phase current is modulated by the SRMs inductance. The current is demodulated and combined with the output of a state observer to produce an error input to the observer so that the observer will track the actual SRM rotor position. The strategy can determine the SRMs rotor position at standstill and low speeds with torques up to rated torque. Another observer, named the simplified flux model based observer, is used for medium and high speeds. In this case, the flux is computed using the measured current and a simplified flux model. The difference between the computed flux and the measured flux generates an error that is input to the observer so that it will track the actual SRM rotor position. Since the speed ranges of the two control stragegies overlap, the final control system is capable of working from zero to high speed by switching between the two observers according to the estimated speed. The stability and performance of the observers are verified with simulation and experiments.

In this study, development of software, which can analyze and optimize an SRM by accurately calculating its performance, is aimed. Existing methods in the literature are investigated. Some studies for the calculation of performance use 2D field solutions and are known to be accurate / however, using field solutions is not feasible for the optimization purpose. So, a method based on a set of normalized permeance and force data are chosen for prediction of magnetizing characteristics. Selected methods are programmed into the software with a user friendly interface. The results from the software are compared with test results from an existing motor. It is found that the accuracy of the predictions is not acceptable if the effect of end winding leakage flux is not accounted for. An approach is proposed for accounting the end winding leakage. The software is modified accordingly. In this case, the results obtained are found to have good accuracy, compared with measurements. The SR motor design optimization problem is treated as a constrained wieght optimization problem. This problem is converted to an unconstrained optimization problem, by using the Augmented Lagrangian method. To decrease the computation time of some of the performance calculation algorithms, some modifications are made. These are described in the related sections. The derivatives for the optimization process are numerically calculated. The accuracy of the performance calculation is once again verified against test results at this stage. The optimization software is then used to optimize the design of an SR motor for a washing machine application. The results obtained are discussed.

Thesis (MEng)--University of Stellenbosch, 2000. / ENGLISH ABSTRACT: This thesis deals with the design and optimisation of medium power traction switched reluctance machines with tapered and straight stator poles. Only the prototype of the tapered stator pole machine is constructed and evaluated in this study. A non-commercial finite element package is used in the design and optimisation of the machines. The finite element method is applied directly in the optimisation procedure to optimise the design of the machines in multi-dimensions. The lumped circuit analysis method is used only for the purpose of verifying some of the finite element calculated. It is not used in the optimisation procedure. The performance characteristics of the tapered and straight stator pole machines are compared and discussed and the tapered stator pole machine is found to have better torque performance. Also the calculated and measured static torque versus rotor position characteristics of the tapered stator pole machine are compared and discussed. / AFRIKAANSE OPSOMMING: Die tesis beskryf die ontwerp en optimering van medium drywing trekkrag geskakelde reluktansie masjiene met tapse en reguit stator pole. Slegs 'n prototipe van die tapse stator pool masjien is gebou en geëvalueer. Die masjiene is ontwerp en geoptimeer met behulp van 'n nie-kommersiële eindige element metode pakket. Die eindige element metode is direk in die optimerings algoritme gebruik vir die optimering van die masjiene in multi-dimensies. Die gekonsentreede parameter stroombaananalise is slegs gebruik om sommige van die eindige element berekenings te verifeer. Die vermoës van die tapse en reguit stator pool masjiene is vergelyk en bespreek. Die resultate toon dat die tapse stator pool masjien se draaimoment vermoë beter is as die van die reguit stator pool masjien. Die berekende en gemete statiese draaimoment teenoor rotorposisie van die tapse stator pool masjien is ook vergelyk en bespreek.

Made available in DSpace on 2014-07-29T15:08:20Z (GMT). No. of bitstreams: 1 anexo dissertacao weldon.pdf: 502529 bytes, checksum: e010c8b9335a273bd3a0c2fd72779737 (MD5) Previous issue date: 2009-06-30 / This work presents a proposal for testing Switched Reluctance Motors, which is feasible by the design and construction of an automated test bench. The test proposal intends to measure phase s resistance; to compute copper loss; to obtain the magnetizing curves for aligned and unaligned rotor and a performance test, which is based on fixing the under test motor rotor speed by a drive machine that is drove by a frequency inverter. The computational automation is restricted in changing the d.c. voltage applied to the under test switched reluctance motor by a programmable sinusoidal voltage source; changing and/or fixing the under test rotation speed of the switched reluctance; changing the semiconductor-switch switching angle; acquisition and processing of the data obtained in the tests. Computational simulations were performed for validating tests results made in an available switched reluctance motor / Este trabalho apresenta uma proposta de ensaios de Motores a Relutância Chaveados, a qual se viabiliza através do projeto e construção de uma bancada automatizada. A proposta de ensaios compreende, entre outros procedimentos, em medir as resistências das fases; calcular a perda ôhmica; determinação das curvas de magnetização nas posições de pólos, do estator e rotor, alinhados e desalinhados e o desempenho, o qual se fundamenta na fixação da velocidade de rotação dos motores sob teste através de uma máquina de indução trifásica de grande potência comparada à potência do motor sob teste, cujo acionamento é realizado por meio de um conversor de freqüência. A automação realizada via computacional está circunscrita aos seguintes aspectos: variação da tensão de corrente contínua aplicada ao motor a relutância; variação e fixação da velocidade de ensaio do motor a relutância; variação do ângulo de disparo das chaves semicondutoras do conversor de potência; aquisição e processamento dos dados obtidos nos ensaios e determinação da velocidade do motor. Através do método dos elementos finitos foram realizadas simulações computacionais pertinentes para confrontar com os ensaios realizados em um motor a relutância chaveado disponível.