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A Study of Field-Oriented Control of a Permanent Magnet Synchronous Generator and Hysteresis Current Control for Wind Turbine ApplicationBaktiono, Surya 27 June 2012 (has links)
No description available.
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Real-time torque ripple compensationfor PMSMs in robotics applicationsJieqiong, Wang January 2024 (has links)
The Permanent Magnet Synchronous Motors (PMSM) have wide application in the robotics field due to its efficiency and reliability. As a servo system, it demands high precision in different control applications. Torque ripple is a critical issue resulting in mechanical vibrations and shortening the life of PMSMs, especially at low speeds. Because the magnitude of speed harmonics is proportional to the magnitude of the torque harmonics of the same order, methods to reduce speed harmonics can be utilized for torque ripple minimization. This thesis work proposes three methods for torque ripple reduction. One method is based on harmonic speed control (HSC) and harmonic current control (HCC). Another method uses the fuzzy to adjust PI parameters based on HSC-HCC. The third method utilizes torque ripple estimation (TRE) and HCC. In the proposed methods, torque ripples are estimated using a torque ripple model (TRM). At low speeds, speed harmonics and current harmonics are obtained based on an adaptive linear neural-based filter. The errors between the optimal harmonic current reference from HSC or TRE and the harmonic current from extraction are used to generate harmonic voltage in HCC. This harmonic voltage is fed back to compensate and reduce torque ripple. Furthermore, a feedforward compensation method is proposed to minimize torque ripple across a range of speeds based on the feedback compensation results. Finally, simulations and experiments are carried out to demonstrate the validity and performance of the proposed torque ripple reduction methods.
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Design and Control of A Ropeless Elevator with Linear Switched Reluctance Motor Drive Actuation SystemsLim, Hong Sun 03 May 2007 (has links)
Linear switched reluctance motor (LSRM) drives are investigated and proved as an alternative actuator for vertical linear transportation applications such as a linear elevator. A one-tenth scaled prototype elevator focused on a home elevator with LSRMs is designed and extensive experimental correlation is presented for the first time.
The proposed LSRM has twin stators and a set of translator poles without back-iron. The translators are placed between the two stators. The design procedures and features of the LSRM and the prototype elevator are described. The designed LSRM is validated through a finite element analysis (FEA) and experimental measurements. Furthermore, a control strategy for the prototype elevator is introduced consisting of four control loops, viz., current, force, velocity, and position feedback control loops. For force control, a novel force distribution function (FDF) is proposed and compared with conventional FDFs. A trapezoidal velocity profile is introduced to control vertical travel position smoothly during the elevator's ascent, descent, and halt operations. Conventional proportional plus integral (PI) controller is used for the current and velocity control loops and their designs are described. The proposed control strategy is dynamically simulated and experimentally correlated. Analytical and experimental results of this research prove that LSRMs are one of the strong candidates for ropeless linear elevator applications.
However, the proposed FDF is assuming that the feedback current signals are ideal currents indicating actual phase currents without any measurement disturbances mainly arising from sensor noise, DC-link voltage ripple, measurement offset, and variations in the plant model. Meanwhile, real control systems in industry have measurement disturbance problems. Phase current corrupted by measurement disturbances increases torque or force ripple, acoustic noise and EMI. Therefore, this dissertation also presents a novel current control method to suppress measurement disturbances without extra hardware.
The controller is based on an extended state observer (ESO) and a nonlinear P controller (NLP). The proposed method does not require an accurate mathematical model of system and can be implemented on a low-cost DSP controller. The proposed ESO is exploited to estimate the measurement disturbances on measured phase currents, and the proposed NLP compensates for the measurement disturbances estimated by the ESO. The performance of the proposed current control is validated through extensive dynamic simulations and experiments. Moreover, this rejection of measurement disturbances results in a reduction of force ripple and acoustic noise. Due to superior and robust current control performance, it is believed that the proposed method can be successfully applied into other motor drive systems to suppress measurement disturbances with the same promising results without extra hardware. / Ph. D.
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Aplikace ultrakapacitorů v dopravních systémech / Application of Ultracapacitors in Traffic SystemsKalina, Emil January 2008 (has links)
The work deals with relatively new components allowing electric energy accumulation – ultracapacitors. It focuses on their application in traffic systems – in independent electric vehicles. Design and verification of a system with ultracapacitor and DC/DC adaptive converter was done. Control of the adaptive converter modifies very positively the time wafeform of the traction accumulator current during the drive cycle. The designed connection of ultracapacitor and DC/DC converter implemented in the drive structure of experimental electric vehicle with induction machine contributes to increment the action radius of the vehicle by 16% (determined by experimental verification). This result was achived particularly by limitation of traction accumulator current peaks, And by more effective storage of energy gained by recuperative braking of the vehicle as well. The core of the system is a control of the adaptive converter in order to provide an active filtration of the accumulator’s current to its long-period mean value, i.e. elimination of current (power) peaks. These are caused by acceleration from non-zero initial vehicle speed or by recuperative braking. This is done by a subsidiary current loop. The converter has a superior voltage regulation loop, which sets in long-time period the voltage of ultracapacitors to the proper value – indirectly dependent on the speed of the vehicle. This ensures the appropriate energy management of the ultracapacitor. In the following, properties of test set of ultracapacitors were verified. Finally, methods of suppression of capacity variability influence in series connection of these components were compiled and critically reviewed.
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On Power-system Benefits, Main-circuit Design, and Control of StatComs with Energy StorageXie, Hailian January 2009 (has links)
Static synchronous compensation (StatCom) is an application that utilizes a voltage source converter (VSC) to provide instantaneous reactive power support to the connected power system. Conventionally, StatComs are employed for reactive power support only. However, with the integration of energy storage (ES) into a StatCom, it can provide active power support in addition to the reactive power support. This thesis deals with the integration of ES into StatComs. The investigation involves the following aspects: possible benefits for power systems, main circuit design, and control strategies. As the basis of the investigation, a control scheme is proposed for two-level VSCs. It is a novel flux modulation scheme combined with the well-known deadbeat current control. The current controller is capable of controlling the positive sequence, the negative sequence, and the offset components of the converter current. With flux modulation, all the three above-mentioned components of the bus flux are controllable. This differs from the conventional voltage modulation scheme, in which only the positive and negative sequence components of the bus voltage are controllable. The difference between the proposed flux modulation scheme and the voltage modulation scheme is investigated regarding saturation of transformers in the connected system during fault recovery. The investigation shows that by controlling the offset component of the bus flux, the transformer saturation problem can be mitigated to a certain extent. The possible benefits of the additional active power support of StatComs are investigated through several case studies. Different active power compensation schemes are proposed. First, active power compensation for sudden load changes in weak systems is investigated. The proposed control strategies are verified through computer simulations and through experiments in a real-time simulator. It is shown that with active power compensation, both the phase jumps and magnitude variations in the voltage at the PCC can be reduced significantly. Secondly, the power compensation of cyclic loads is investigated. The results show that the power quality at the connection point can be improved regarding both phase jumps and magnitude variations. In the third case study, the fault-recovery performance of an example system is investigated, showing that improved performance can be achieved by the additional active power support. ES devices such as capacitors, supercapacitors, and batteries exhibit considerable variation in the terminal voltage during a charging/discharging cycle. A direct connection of ES devices to the dc side of a VSC requires a higher voltage rating of the VSC. Thus, the cost of the VSC has to be increased. In this thesis, a dual thyristor converter topology is proposed to interface ES devices with the dc side of the VSC. First, a cost comparison is performed to compare the total cost of the whole system with and without the proposed interface topology. A cost comparison between various types of ES is also presented, providing a guideline for the choice of ES at energy levels where several alternatives exist. Then, the dynamics of systems with the proposed interface topology are investigated. Control strategies are proposed and verified by computer simulations. Two different control methods for the dual-thyristor converter are compared. / QC 20100819
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Controle de corrente aplicado a conversores PWM conectados à rede elétrica sem sensor de tensão CA utilizando observadores de corrente por modos deslizantes / Sliding mode observer for a voltage sensorless current control of grid connected PWM convertersTonin, Rodrigo Gehrke 22 August 2014 (has links)
Coordenação de Aperfeiçoamento de Pessoal de Nível Superior / This master thesis presents a current sliding mode observer for voltage sensorless
grid connected converters. To perform the grid synchronization a sliding mode current
observer in stationary axes αβ is proposed. Aiming its implementation in digital signal
processors or microcontroller both the synchronism and control are developed in discrete
time domain. Firstly the line currents are measured, then the transformation to stationary
axes is carried out and the sliding mode current observer is proposed. Based on
a Fortescue discrete component theory an algorithm to separation of sequence positive
phase is proposed aiming to obtained the positive grid angular position to realized the
synchronous coordinates axes transformation. The current control is carried out by two
PI controllers designed in a discrete time domain. The good performance of the proposed
method is proven through the simulation and experimental results. / Esta dissertação apresenta o controle de corrente em eixos síncronos de conversores
conectados a rede de energia elétrica sem o uso de sensores de tensão de linha. Para realizar
o sincronismo com a rede elétrica é proposto um observador de corrente por modos
deslizantes em eixos de coordenadas estacionárias αβ. Tanto o controle como o sincronismo
são desenvolvidos em tempo discreto visando sua implementação em processador
digital de sinais ou microcontrolador. Primeiramente são medidas as correntes de duas
fases do sistema, então é realizada a transformação para eixos estacionários e proposto o
observador de corrente por modos deslizantes. Com o auxílio de um algoritmo baseado
na teoria das componentes discretas de Fortescue para a separação de sequência de fase
positiva, é obtida posição angular elétrica da rede visando a transformação para eixos de
coordenadas síncronas. O controle das correntes é realizado através de dois controladores
PI projetados em tempo discreto. Através de resultados de simulação e experimentais
obtidos é comprovado o bom desempenho do método proposto.
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CONTROLE POR MODOS DESLIZANTES E OBSERVADOR DE DISTÚRBIOS APLICADOS AO MOTOR SÍNCRONO DE ÍMÃS PERMANENTES / CURRENT CONTROL PERMANENT MAGNET SYNCHRONOUS MOTORGabbi, Thieli Smidt 20 August 2015 (has links)
Coordenação de Aperfeiçoamento de Pessoal de Nível Superior / This master thesis proposes a current control technique based on sliding mode strategy
and disturbance observer for high-performance drive applied to permanent magnet
synchronous motors and can be extended to other systems. The combination of sliding
mode control and disturbance observer applied to the current control presents the characteristics
necessary to minimize the coupling between the axes, rejection of external
disturbances and parametric variations. A continuous time control scheme is developed,
the stability proofs are performed from the Lyapunov analysis. The performance of the
propose technique is evaluates through simulation results. Moreover, this master thesis
presents a discrete-time sliding mode controller combined with a discrete-time disturbance
observer. The development in discrete-time enables the implementation in digital processors.
The conditions of reach of the proposed controller considering the transport delay
of digital implementation are still evaluated. The stability proofs of the proposed scheme
are presented. Simulation results are shown. In addition, it is developed an experimental
platform for drive and control of the permanent magnet synchronous motor in which the
experimental results are obtained. / Esta dissertação propõe uma técnica de controle de corrente baseada na estratégia
por modos deslizantes e observador de distúrbios para acionamento de alto desempenho
aplicada a motores síncronos de ímãs permanentes, podendo ser estendida a outros sistemas.
A combinação do controle por modos deslizantes e do observador de distúrbio
aplicada ao controle de corrente apresenta as características necessárias para minimização
do acoplamento existente entre os eixos, rejeição a distúrbios externos e variações paramétricas.
É desenvolvido um esquema de controle em tempo contínuo, são apresentadas as
provas de estabilidade a partir de critério de Lyapunov. O desempenho da técnica proposta
é avaliado através de resultados de simulação. Além disso, é apresentado um controlador
por modos deslizantes associado ao observador de distúrbio em tempo discreto. O desenvolvimento
em tempo discreto possibilita a implementação em processadores digitais de
sinais. Ainda são avaliadas as condições de alcance do controlador proposto considerando
o atraso de transporte da implementação digital. Provas de estabilidade do esquema proposto
e resultados de simulação são apresentados. Este trabalho faz o desenvolvimento
de uma bancada experimental para o acionamento e controle do motor síncrono de ímãs
permanentes na qual são obtidos os resultados experimentais apresentados.
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Projeto e implementação de lâmpadas para iluminação de interiores empregando diodos emissores de luz(LEDS) / Design and implementation of interior lighting systems using light emitting diodes(LEDS)Pinto, Rafael Adaime 31 October 2008 (has links)
Coordenação de Aperfeiçoamento de Pessoal de Nível Superior / This work presents an efficient lighting system using high intensity light emitting
diodes (LEDs). The goal is to develop a compact and low cost electronic circuit to drive and
control the current of LEDs disposed in a single enclosure. The proposal aims energy saving,
high luminous efficacy and high useful life when replacing traditional lighting systems, as
dichroic, incandescent or compact fluorescent lamps by LEDs without any change in
electrical system installation. Furthermore, an emergency lighting system integrated into the
lamp is proposed, allowing the use of the same equipment in the daily activities, supplied by
mains, and under a possible break in the electrical network. To supply the LEDs through the
mains with universal input voltage and charge the battery, a Buck converter was employed. To
supply the LEDs with a continuous current through the battery, a Boost converter was used.
The converters operate at high frequency and control the current through the LEDs
independently. The battery can be composed of three rechargeable Ni-MH batteries (1,2 V) or
a Li-ion battery (3,6 V). The design attends the Brazilian standard and international standard
for emergency lighting systems. To validate the proposed idea, the circuits were designed and
implemented. The experimental results are shown with the intention to prove the satisfactory
behavior of the lamps. / Este trabalho apresenta um sistema de iluminação eficiente empregando diodos
emissores de luz (LEDs) de alta intensidade. O objetivo é desenvolver um circuito eletrônico,
compacto e de baixo custo, para acionamento e controle da corrente dos LEDs contidos em
um único invólucro. A proposta visa a racionalização no uso da energia elétrica através de
uma elevada eficácia luminosa e longa vida útil na substituição dos sistemas de iluminação
tradicionais, como lâmpadas dicróicas, incandescentes ou fluorescentes compactas, por LEDs
sem qualquer alteração na instalação elétrica. Além disso, é proposto um sistema de
iluminação de emergência integrado a esta lâmpada, permitindo a utilização de um único
equipamento para iluminação convencional, alimentada pela rede elétrica, e sob uma possível
falha no fornecimento de energia. Para alimentar os LEDs, através da rede elétrica, com
tensão de entrada universal e ainda carregar a bateria, um conversor Buck é empregado. Para
alimentar os LEDs em corrente contínua através da bateria, um conversor Boost é utilizado.
Os conversores operam em alta freqüência e controlam a corrente nos LEDs de forma
independente. A bateria pode ser composta por três pilhas recarregáveis de Ni-MH (1,2 V) ou
por uma bateria de Li-Ion (3,6 V). O projeto atende às exigências da norma brasileira (NBR
10898) e da norma internacional (IEEE Std 446-1995) para sistemas de iluminação de
emergência. Para analisar a idéia proposta, os circuitos são projetados e implementados. Os
resultados experimentais são apresentados de forma a comprovar o comportamento
satisfatório das lâmpadas.
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Estudo de técnicas de controle de máquinas de relutância chaveada para aplicações em sistemas de acionamentos com velocidade variávelAlmeida, Lucas Alves de 27 February 2018 (has links)
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Previous issue date: 2018-02-27 / Sistemas eletromecânicos são de grande importância atualmente, e a procura por maior eficiência e desempenho aliados a um menor custo justificam a busca por alternativas tanto em topologia quanto no controle e acionamento de tais sistemas. A máquina de relutância chaveada é capaz de cumprir estes requisitos e tem despertado o interesse de pesquisadores e empresas nos últimos anos, emergindo como uma alternativa viável em diversas aplicações. Porém, esta máquina possui características singulares. Por conta de sua estrutura duplamente saliente, seu funcionamento correto depende da aplicação de pulsos de corrente por determinados intervalos de tempo, e na sequência correta, seus parâmetros são variáveis no tempo, apresentando um comportamento com características não-lineares. Tais particularidades fazem com que seja difícil controlar o torque destas máquinas, as quais possuem a tendência de apresentar altas oscilações durante a mudança da excitação de cada fase. Este trabalho tem por objetivo contribuir com o estudo da modelagem e do acionamento de uma máquina de relutância chaveada. É apresentada sua modelagem matemática e um modelo de simulação que leva em consideração as não linearidades existentes. Em seguida são apresentadas técnicas de controle de corrente que incluem um regulador de histerese, um controlador PI e um controlador por modos deslizantes. Também é utilizado um método capaz de determinar o momento em que cada fase deve ser acionada, baseado no ângulo do rotor, e uma técnica de variação dos ângulos de acionamento de maneira dinâmica, usados em conjunto com os controladores propostos. O trabalho também caracteriza e apresenta as funções de divisão de torque como uma maneira de reduzir drasticamente as oscilações de torque. São apresentadas as operações como motor e como gerador, bem como um exemplo de aplicação de modo a ilustrar ambos os modos de operação. / Electromechanical systems have a huge relevance nowadays, and seeking for improvements in efficiency and performance at the lowest cost make valid to identify topological and control alternatives of these systems. The switched reluctance machine is capable to fulfill such requirements and emerges as an interesting field of research. Academics and industrial works shows that it is a promising alternative in several applications. However, this machine presents unique characteristics, like the doubly salient structure, the necessity to apply phase currents in a sequence determined by the stator/rotor pole ratio, its time variantparameters,andthestrongnonlinearcharacteristics. Suchsingularitiesmaketorque control hard, as it tends to present high ripples and makes a lot of noise. This thesis aims to contribute on switched reluctance machine modeling and drive system. A mathematical model is presented, and also a simulation model that accounts for nonlinearities, making possible to simulate the machine accurately in a computational environment. A hysteresis regulator, a PI controller and a sliding mode controller are designed and simulated. An algorithm to determine when each phase should be excited based on rotor angle is used, and a technique to change such firing angles dynamically is developed that can be used along with current control methods presented. The work also defines and presents torque sharing functions as a way to greatly reduce torque ripple. Motor and generator operation are contemplated, and both modes are illustrated in an application example.
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Trakční pohon elektrokola s motorem Heinzmann / A traction drive for an electric bike with motor "Heinzmann"Němec, Petr January 2008 (has links)
This work deals with a proposal and construction of a DC/DC converter for a control of a DC motor Heinzmann. The DC/DC converter will be used in an electric drive for a bicycle. The proposal of the DC/DC converter is designed for such engine power to avoid fully any human force to drive - pedaling. The work includes informations about the used motor, progress of proposal and dimensioning of the converter - power circuit and control electronics.
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