Дисертації: "Closed loop delay compensation"

1

PEROTTI, MICHELE. "Software Solutions to Mitigate the Electromagnetic Emissions of Power Inverters." Doctoral thesis, Politecnico di Torino, 2020. http://hdl.handle.net/11583/2842505.

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2

Myklebust, Andreas. "Closed Loop System Identification of a Torsion System." Thesis, Linköping University, Department of Electrical Engineering, 2009. http://urn.kb.se/resolve?urn=urn:nbn:se:liu:diva-17531.

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A model is developed for the Quanser torsion system available at Control Systems Research Laboratory at Chulalongkorn University. The torsion system is a laboratory equipment that is designed for the study of position control. It consists of a DC motor that drives three inertial loads that are coupled in series with the motor, and where all components are coupled to each other through torsional springs.

Several nonlinearities are observed and the most significant one is an offset in the input signal, which is compensated for. Experiments are carried out under feedback as the system is marginally stable. Different input signals are tested and used for system identification. Linear black-box state-space models are then identified using PEM, N4SID and a subspace method made for closed-loop identification, where the last two are the most successful ones. PEM is used in a second step and successfully enhances the parameter estimates from the other algorithms.

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3

Moon, Seung Ryul. "Hybrid PWM Update Method for Time Delay Compensation in Current Control Loop." Diss., Virginia Tech, 2017. http://hdl.handle.net/10919/84929.

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A novel hybrid pulse-width modulation (PWM) update method is proposed to eliminate the effect of the one-step control time delay Td one without losing the full duty cycle range. Without the Td one to cause linear phase shifts that limit the control bandwidth and affect closed-loop stability, a very high quality digital current control can be achieved, such as a high closed current loop bandwidth, strong robustness against disturbances, ability to reach a very high fundamental frequency compared to switching frequency, etc. In a conventional digital control implementation, a sampling period (Tsamp) is allocated for the execution of samplings and computations, and the update of PWM outputs is delayed until the beginning of the following sampling period. This delayed PWM update method is the cause of the Td one. Instead of the delayed PWM update, if the PWM outputs are updated immediately after algorithm computations, then the effect of the Td one can be eliminated; however, the computation time delay Td comp from the current sampling instant through algorithm computations to the PWM update instant causes a reduced duty cycle range. Each of these two conventional PWM update methods has some shortcomings. A hybrid PWM update method is proposed to circumvent the aforementioned shortcomings and to incorporate only the advantages. The proposed method improves the performance by updating the PWM outputs multiple times during a Tsamp, whereas the PWM outputs are updated only one time during a Tsamp in the conventional methods. In spite of the simplicity of the proposed method, the performance improvements in stability, robustness and response characteristics are significant. On the other hand, the proposed method can be easily applied to many PWM based digital controls because of its simplicity. Additional to the hybrid PWM update method, a hybrid control method is proposed to optimize the sequence of control operations. It maximizes the current loops' robustness and minimizes the delay from the sampling of outer control loops' variables, such as voltage and speed, to the duty cycle update instant. The minimum delay enables the maximization of the outer control loops' bandwidth. Additionally, a corrective neutral offset voltage injection method is proposed to correct small PWM output deviations that may occur with the hybrid PWM update method. Utilizing a three-phase voltage source inverter with a permanent magnet synchronous machine as the platform, a deadbeat current control and a high speed ac drive experiments have been conducted to demonstrate the feasibility and validity. Notable results include a closed current loop response of one Tsamp with the deadbeat control and a 500 Hz current fundamental frequency with 1 kHz switching frequency in the high speed ac drive.
Ph. D.

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4

Saarinen, I. (Ilkka). "Reverse link feedback power control in pilot symbol assisted systems." Doctoral thesis, University of Oulu, 2000. http://urn.fi/urn:isbn:9514257626.

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Abstract Reverse link feedback power control in subject to a feedback delay and in conjuction with diversity is considered over a frequency-nonselective slow Rayleigh fading channel. The transmission power of a mobile station is adjusted as a function of fed back estimated channel state information, so that the average error probability is minimized when the average transmission power is fixed. The channel state is estimated by using known, constant-power pilot symbols. In each frame, a time multiplexed pilot symbol is transmitted in addition to the antipodal data symbols. In the literature, feedback MMSE (minimum mean-square error) power control has been analyzed in the case of a random time-invariant channel. Therein the frame size was two, i.e. one data and one pilot symbol were transmitted in each frame. Also, the fading gain was estimated by a one-shot MMSE estimator. This author's main contribution is that the aforementioned analysis has been extended to a more general system model in which the frame size is arbitrary, and in which the time-variant fading gain is estimated by an optimal MMSE estimator. For power control purposes, the estimator has to be a predictor since feedback requires causality. First, in order to avoid a delay in detection, the predictor is used in both power control and detection. In the case of a frame size of two, the performance of feedback MMSE power control employing the predictor is compared to that of a system using the one-shot estimator. Then, the performance of feedback MMSE power control with an optimal frame size is evaluated. Finally, the system performance is derived when a smoother is employed in detection, and the additional effects of a feedback delay and diversity on the performance are investigated. The performance difference between optimal (channel states are assumed to be known) and MMSE power control using a one-shot estimator is found to be significant at large signal-to-noise ratios (SNR's). This is in contradiction with the result presented earlier in the literature. The reason for the large performance difference is that the SNR of the channel estimate is small, since each estimate is computed using only one pilot symbol. The performance difference between optimal and MMSE power control with the predictor is smaller than said difference in the case of the one-shot estimator because the estimate is averaged over many pilot symbols. It is also observed that the lag error of the estimator considerably reduces the benefit of MMSE power control, even when the channel changes very slowly. To diminish the lag error, and to achieve good performance, a large number of estimator coefficients is required. It is well known that fixed-step adjustment closed loop power control attempts to compensate for all changes caused by the channel. In contrast, according to Monte Carlo simulations, MMSE power control did not attempt to compensate for the deepest fades. At other time instants, it strives to set the received SNR to an approximately constant level, which depends on the bit-error rate (BER) target. Increasing the frame size from the value of two not only improves the spectrum utilization, but was also shown to yield better performance for the pilot symbol system with MMSE power control over a slowly fading channel. Also, a clear performance improvement was achieved by using the smoother in detection. The performance loss resulting from a feedback delay of 10-20 % from the channel coherence time was shown to be small with reasonable BER values. Estimation errors were shown to diminish the benefit of power control when the diversity order was two, compared to the case of no diversity.

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5

Cesaretti, Juan Manuel. "Mechanical stress and stress compensation in Hall sensors." Thesis, Atlanta, Ga. : Georgia Institute of Technology, 2008. http://hdl.handle.net/1853/28202.

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6

Kichel, Caetano Bevilacqua. "Metodologia não intrusiva para estimação do tempo morto em sistemas monovariáveis." reponame:Biblioteca Digital de Teses e Dissertações da UFRGS, 2017. http://hdl.handle.net/10183/172072.

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Dentre os fatores limitantes dos sistemas de controle, o tempo morto está entre os mais críticos e de difícil detecção sem testes intrusivos. O conhecimento do seu valor é essencial para a identificação de modelos e na auditoria de desempenho de sistemas de controle. Em virtude disto, o presente trabalho propõe uma metodologia eficaz para estimá-lo utilizando apenas dados históricos de processo em malha fechada. A principal vantagem frente a técnicas disponíveis na literatura é a não necessidade de testes intrusivos. A metodologia é baseada em um tratamento de sinal para remoção dos efeitos do distúrbio não medido e dos erros de modelo. O tratamento de sinal consiste na minimização das oscilações do sinal erro em malha aberta suavizado como função do tempo morto. Diversas formulações de função objetivo e procedimentos de suavização foram estudados visando facilitar a estimação do parâmetro. A qualidade da metodologia é ilustrada através de simulações em uma série de cenários, os quais simulam processos lineares de diferentes características sob o efeito de distúrbios distintos. A metodologia também é testada frente a estudo de casos com dados reais de processo industrial em malhas de nível e temperatura. Os resultados são comparados com métodos da literatura e demonstram que o método proposto foi eficaz na estimação do tempo morto para a maioria dos casos.
Among the limiting factors of control systems, the pure time delay is one of the most critical and difficult to estimate without an intrusive perturbation. The knowledge of its value is essential for model identification and control loop performance assessment. This work proposes a methodology to determine dead time using ordinary closed loop operating data. The main advantage over available techniques is the non-necessity of intrusive plant tests. The proposed approach is based on a signal processing for removing the effects of the unmeasured disturbances and the model-plant mismatches. The signal processing consists of the minimization of the oscillations of the smoothing open loop error as a function of the pure time delay. Several objective function formulations and smoothing procedures were studied in order to facilitate parameter estimation. The quality of the methodology is illustrated by simulations in a series of scenarios, which simulate linear processes of different characteristics under the effect of different disturbances. The methodology is also tested in case studies with real industrial process data. Results are compared to literature approaches and show the method was effective to estimate the pure time delay for most cases.

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7

Talarcek, Steven C. "An Experimental Study of Disturbance Compensation and Control for a Fractional-Order System." University of Akron / OhioLINK, 2018. http://rave.ohiolink.edu/etdc/view?acc_num=akron1542303891784113.

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8

Ramesh, Chithrupa, Henrik Sandberg, and Karl Henrik Johansson. "Stability analysis of multiple state-based schedulers with CSMA." KTH, Reglerteknik, 2012. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-111461.

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In this paper, we identify sufficient conditions for Lyapunov Mean Square Stability (LMSS) of a contention-based network of first-order systems, with state-based schedulers. The stability analysis helps us to choose policies for adapting the scheduler threshold to the delay from the network and scheduler. We show that three scheduling laws can result in LMSS: constant-probability laws and additively increasing or decreasing probability laws. Our results counter the notions that increasing probability scheduling laws alone can guarantee stability of the closed-loop system, or that decreasing probability scheduling laws are required to mitigate congestion in the network.

QC 20130116

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9

Calou, Paul. "Mesure et compensation de bâtiments navals à l’aide de capteurs magnétiques trois composantes." Thesis, Strasbourg, 2019. http://www.theses.fr/2019STRAH018.

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Cette thèse s’établit à la frontière du géomagnétisme et du magnétisme du navire, deux disciplines proches mais dont les habitudes diffèrent. Dans un premier temps, on présente les spécificités de chaque domaine en introduisant les principales notions clés ainsi que le type de mesure mis en oeuvre pour chaque domaine et les géométries d’acquisition. On vérifie également la validité des approximations utilisées dans les cas de figure rencontrés. Dans un deuxième temps (chapitre 2 et 3) on détaille le lien mathématique possible entre l’anomalie scalaire utilisée en géophysique et les trois composantes du champ d’anomalie. Le chapitre 4 résume les travaux expérimentaux réalisés, on présente le banc de test utilisé ainsi que les résultats obtenus sur données synthétiques et réelles pour la problématique de réglages des boucles d’immunisation. Dans le chapitre 5, une nouvelle approche concernant l’immunisation en boucle fermée pour un navire est présentée. On montre également un exemple de compensation réalisée sur un vrai navire à l’aide de capteurs embarqués. La thèse se termine avec le chapitre 6 qui est un article soumis à une revue scientifique synthétisant les problématiques de la thèse
This PhD thesis aims to apply geophysical practices to another magnetic branch which deals with ship’s signature and magnetization with different methods and habits. Firstly, we present the specificity and practices of each domain, introducing the key notions as well as the differences between each kind of measurement. We check the validity of the approximation corresponding to total-field magnetic anomalies in the particular case of our measurements. In a second time, chapter 2 and 3, a mathematical relation is demonstrated between the scalar anomaly and the three components of the anomaly field based on the equivalent layer method. Chapter 4 summarize the experimental work, focusing on the determination of the best electrical current to compensate the ship’s magnetic signature. The experimental system is presented as well as the main results obtained. In chapter 5, a new approach for closed loop degaussing system is presented, based on a compensation algorithm. We also show some results obtained thanks to the compensation with three-component magnetometers onboard a real ship. Chapter 6 corresponds to an article submitted to a scientific journal (IEEE) that summarize most of the problematics of the thesis

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10

Miranda, Filipe Costa Pinto dos Reis. "Identificação de sistemas em malha fechada usando controlador preditivo multivariável: um caso industrial." Universidade de São Paulo, 2005. http://www.teses.usp.br/teses/disponiveis/3/3137/tde-19082005-151031/.

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A Identificação de Sistemas é uma tarefa significativa em termos de tempo e custo no trabalho de implementação de sistemas de controle que usam Controle Preditivo baseado em Modelos (MPC). Após a implementação, o controlador tende a permanecer com o mesmo modelo por muito tempo, ignorando mudanças que tenham ocorrido com o processo, perdendo qualidade e podendo até ser abandonado. Este trabalho propõe uma metodologia simples e eficaz para se proceder à reidentificação de uma planta industrial que use MPC mantendo o processo em malha fechada. Os principais aspectos deste problema são discutidos, e as escolhas que foram feitas para a realização dos experimentos e obtenção dos modelos são explicadas. Apresenta-se um caso em Matlab sobre um sistema 2x2 cobrindo diferentes situações, e é feita uma comparação de identificação realizada através de sinais PRBS e de testes com degraus, sempre em malha fechada. Aplica-se a metodologia a um controlador industrial, e os modelos identificados são introduzidos no controlador. O princípio básico desta metodologia consiste em efetuar perturbações multivariáveis nos set-points ou restrições ativas das controladas e determinar o modelo através da estrutura ARX. Entre as vantagens da metodologia proposta, estão a facilidade de automatizar a identificação do processo e a garantia de manter o processo sob controle durante os testes.
System identification is a major task in the process of implementing Model-based Predictive Control (MPC) algorithms in industrial applications. Once the controller is working, there is a tendency to leave it with the original model for a long time, neglecting changes to the process during this time, leading to performance degradation. This work proposes a simple and effective methodology to re-identify plants under MPC in closed loop. The main issues concerning this problem are discussed, and choices for experiments are made. A Matlab case involving a 2x2 problem is presented, covering a range of different situations, and a comparison between identification using PRBS reference signals and standard step tests is shown. An industrial case is studied, applying the proposed method to a real situation, re-identifying an existing MPC model and reconfiguring it afterwards. This methodology is based on the application of multivariable perturbations on the controlled variables set-points or active restrictions, obtaining an ARX model structure. It uses an automatic process identification proceeding, keeping the process under control along the tests.

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Saligane, Mehdi. "Adaptive body biasing system for margins reduction using delay and temperature monitoring at near threshold operation." Thesis, Aix-Marseille, 2016. http://www.theses.fr/2016AIXM4716.

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La conception de circuit à très faible tension d'alimentation est un moyen depuis longtemps connu pour diminuer la consommation d'énergie des circuits pour un même service rendu [VITTOZ weak inversion]. La faible tension permet de gagner à la fois en courant de fuite [K ROY leakage] et surtout en courant dynamique qui reste la partie de l'énergie consommée la plus ardue a maîtriser. Elle s'accompagne d'un délai multiplié par plusieurs ordres de grandeur et une sensibilité accrue aux variations de paramètres des dispositifs. Cette variation étant plus grande dans les technologies récentes, la conception à très faible tension était jusqu'à récemment limitée aux nœuds technologiques en deçà de 40nm, mais des avancées récentes en technologie 32nm ont été publiés [TI ISSCC2011]. Un premier travail de thèse [ABOUZEID PhD], a permis de confirmer la faisabilité de la conception de circuit ULV. Plus précisément ont été démontrées : · une méthodologie de conception de cellules logiques en technologie 90nm, 65nm, 45nm et 40nm · une adaptation des flots automatiques d'implémentation et de vérification en 40nm · un précurseur de SRAM en CMOS65nm Sur cette base le présent travail de thèse consistera en l'élargissement de l'éventail du champ de conception ULV vers la gestion d'alimentation, la compensation des conditions environnementales et l'optimisation architecturale afin de préparer l'industrialisation de futures applications ULV
IoT applications continue to push towards ultra-low-power constrained ASICs, creating severe challenges to achieve sufficient power efficiency in extreme Voltage and Temperature conditions. Thus, it is necessary to build closed-loop compensation systems that are autonomous to environmental conditions especially temperature at sub-threshold regime. Two major work are proposed: an adaptive techniques that allow to enhance the performance of designs that leverage aggressive voltage scaling. we fully exploits the FD-SOI 28nm technology dual gate capabilities to both attain optimal power efficiency points and compensate for gradual changes in overall device performance due to process, voltage, and temperature variations. Our proposed compensation Unit system is a fully-digital error-prediction solution providing a compromise between industry reliability requirements and manufacturing guard-band reduction with low-invasiveness and post-silicon tunability. Critical-Paths timing monitors are distributed across the processor and tuned to match the closest critical paths. A programmable workload emulator allows to adapt and take into account the processor tasks. Generated warning Flags due to V-T variations are analyzed based on an adjustable warning rate and body bias is adapted correspondingly. Based on the operation voltage, either fine or coarse body biasing can be activated for compensation. The second part of this thesis addresses on-chip temperature monitoring that plagues aggressively voltage scaled ASICs. We propose to closely monitor temperature fluctuations at low-voltage but also hot-spot detection at nominal and over-drive supply voltage conditions

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12

Merkl, Ralf [Verfasser], Jörg [Akademischer Betreuer] Franke, Jörg [Gutachter] Franke, Christian [Gutachter] Rehtanz, Dirk [Gutachter] Westermann, Jörg [Herausgeber] Franke, Nico [Herausgeber] Hanenkamp, Marion [Herausgeber] Merklein, Michael [Herausgeber] Schmidt, and Sandro [Herausgeber] Wartzack. "Closed-Loop Control of a Storage-Supported Hybrid Compensation System for Improving the Power Quality in Medium Voltage Networks / Ralf Merkl ; Gutachter: Jörg Franke, Christian Rehtanz, Dirk Westermann ; Betreuer: Jörg Franke ; Herausgeber: Jörg Franke, Nico Hanenkamp, Marion Merklein, Michael Schmidt, Sandro Wartzack." Erlangen : FAU University Press, 2021. http://d-nb.info/1229194266/34.

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13

Deng, Kangfa, Gerald Gerlach, and Margarita Guenther. "Force-compensated hydrogel-based pH sensor." SPIE, 2015. https://tud.qucosa.de/id/qucosa%3A35185.

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This paper presents the design, simulation, assembly and testing of a force-compensated hydrogel-based pH sensor. In the conventional deflection method, a piezoresistive pressure sensor is used as a chemical-mechanical-electronic transducer to measure the volume change of a pH-sensitive hydrogel. In this compensation method, the pH-sensitive hydrogel keeps its volume constant during the whole measuring process, independent of applied pH value. In order to maintain a balanced state, an additional thermal actuator is integrated into the close-loop sensor system with higher precision and faster dynamic response. Poly (N-isopropylacrylamide) (PNIPAAm) with 5 mol% monomer 3-acrylamido propionic acid (AAmPA) is used as the temperature-sensitive hydrogel, while poly (vinyl alcohol) with poly (acrylic acid) (PAA) serves as the pH-sensitive hydrogel. A thermal simulation is introduced to assess the temperature distribution of the whole microsystem, especially the temperature influence on both hydrogels. Following tests are detailed to verify the working functions of a sensor based on pH-sensitive hydrogel and an actuator based on temperature-sensitive hydrogel. A miniaturized prototype is assembled and investigated in deionized water: the response time amounts to about 25 min, just half of that one of a sensor based on the conventional deflection method. The results confirm the applicability of the compensation method to the hydrogel-based sensors.

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14

Rittmeier, Sebastian. "Systemunterstützte Umformung." Doctoral thesis, Saechsische Landesbibliothek- Staats- und Universitaetsbibliothek Dresden, 2007. http://nbn-resolving.de/urn:nbn:de:swb:14-1193690438091-21707.

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Konsequent betriebener Leichtbau führte und führt weiterhin zu steigender Komplexität in der Blechumformung. Erkenntnisse aus Forschungsaktivitäten zur gezielten Beeinflussung, Regelung und Vollautomatisierung des Tiefziehprozesses konnten jedoch bisher nicht in Großserienpresswerke transferiert werden. Aus diesem Grund wird in dieser Arbeit ein Werkzeugkonzept vorgestellt, welches unter Berücksichtigung der relevanten Randbedingungen eine gezielte lokale Beeinflussung des Umformprozesses ermöglicht. Gleichzeitig gestattet es, mit Hilfe eines neuartigen, optischen Sensorkonzeptes die Geschwindigkeit sowie den Einlaufweg der Platine zu überwachen. Es wird eine methodische Vorgehensweise zur Herstellung von Umformwerkzeugen, auf der neuen Konzeption basierend, beschrieben. Umformsimulationen dienen dabei zur Identifikation von kritischen Bauteilen und deren neuralgischen Zonen. Eine entsprechend angepasste Konstruktion bietet Bauraum für die Implementierung von zusätzlichen Aktuatoren und einem definiert elastischen Einsatz. Abschließende FEM-Analysen mit Volumenmodellen sowie die Kalkulation der Lebensdauer bestätigen eine ausreichende Flexibilität und die erforderliche Dauerfestigkeit. Im Rahmen der experimentellen Analyse konnte eine drastische Verkürzung der Anlaufzeit durch deutlich reduzierten Tuschieraufwand aufgrund der Anpassungsfähigkeit sowie Flexibilität des definiert elastischen Werkzeugkonzeptes nachgewiesen werden. Neben diesem Potential hinsichtlich strukturierter Inbetriebnahmen ermöglicht die Konzeption eine Kompensation von Pressenunterschieden und individuellen Maschinencharakteristika (wie bspw. Stößelverkippungen) wodurch der Transfer von der Einarbeitspresse auf die Produktionsanlage wesentlich weniger Korrekturschleifen hervorruft. Außerdem werden der Qualitätsaufwand (Nachtuschieren) während der laufenden Serienproduktion, Stillstandszeiten und Ausschussquoten stark verringert. Darüber hinaus ergeben sich erweiterte Anwendungsmöglichkeiten bei der Umformung von tailored blanks und aus der Minimierung/Optimierung des Platinenzuschnittes enorme Einsparungs- und Kostenpotentiale. Abschließend werden die Vorteile eines geschlossenen Prozessregelkreises durch die Verknüpfung von Sensorik und Aktorik analysiert. Dabei bestätigt das vorgeschlagene Regelkonzept einer Prozessnachführung die Erhöhung der Prozessstabilität bei schwankenden Prozessparametern durch die gezielte, lokale Verteilung der Flächenpressung. Zuletzt diskutiert der vorliegende Beitrag Transfermöglichkeiten der Verbesserungspotentiale in kommende Serienwerkzeuge vor dem Hintergrund von Kostenrestriktionen und Minimierung des bedientechnischen sowie konstruktiven Aufwandes.

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Adamík, Pavel. "Řízení dynamických systémů v reálném čase." Master's thesis, Vysoké učení technické v Brně. Fakulta informačních technologií, 2009. http://www.nusl.cz/ntk/nusl-236759.

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This thesis focuses on the methodology of controlling dynamic systems in real time. It contents a review of the control theory basis and the elementary base of regulators construction. Then the list of matemathic formulaes follows as well as the math basis for the system simulations using a difeerential count and the problem of difeerential equations solving. Furthermore, there is a systematic approach to the design of general regulator enclosed, using modern simulation techniques. After the results confirmation in the Matlab system, the problematics of transport delay & quantization modelling follow.

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16

Lee, Peter Ming Wong. "Delay compensated fade prediction based CDMA closed loop power control." Thesis, 2004. http://hdl.handle.net/2429/15640.

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Power control is essential in Code Division Multiple Access (CDMA) systems in order to reduce the near-far effect, optimize,the system capacity, and combat the signal degradation due to fading. One problem with Closed Loop Power Control (CLPC) is the delay introduced by power measurement and round-trip delay in the power control loop. We study the impact of power control loop delays on Frame Error Rate (FER) performance under a range of channel conditions. A new CLPC algorithm with delay compensation and fade prediction is then proposed to mitigate the effects of loop delays on CLPC. Delay compensation can reduce power oscillation amplitude around the desired received power level and fade prediction can forecast an upcoming fade in order to mitigate its effect. The FER performance on the forward link of an Interim Standard - 2000 (IS-2000) CDMA system using the delay compensated fade prediction based CLPC algorithm is studied. Simulations with a detailed IS-2000 physical layer model and various Third Generation Partnership Project 2 (3GPP2) channel models are used to illustrate the performance gains of the proposed CLPC algorithm over the conventional CLPC algorithm. The performance of the proposed CLPC algorithm as a function of mobile speed, delay, and carrier frequency is analyzed. It is found that the proposed CLPC algorithm performs better than the conventional CLPC algorithm by about 1 dB for a range of mobile speeds of interest. The performance improvement obtainable by using the proposed CLPC algorithm can reduce the interference and result in an increase in the system capacity. Finally, the effect of power control bit (PCB) errors on the performance of the proposed CLPC algorithm is studied. Simulation results indicate that the proposed CLPC algorithm is still beneficial when the PCB error rate is 5%.

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17

Ho, Jyun-Che, та 何峻徹. "On Loop Delay Compensation Design for Continuous-Time ΣΔ ADC". Thesis, 2007. http://ndltd.ncl.edu.tw/handle/00065990850436789392.

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碩士
國立交通大學
電機與控制工程系所
96
A ΔΣ modulator is well-known as a very efficient technique for the implementation of high resolution A/D converters in low to medium bandwidth applications. Comparing with switched-capacitor (discrete-time) technique in the past, the continuous time circuitry is more suitable for today’s growing bandwidth applications. The thesis presents the implementation of a ΔΣ modulator with continuous-time techniques. Different numbers of digital delay in the ΔΣ feedback loop have been analyzed based on mathematic theorems in detail. The chip is designed with 1.8V power supply by using 0.18μm TSMC CMOS process, with power consumption 6.5mW and the core area 0.05mm2. The simulation result shows that the ADC achieves a 62dB peak signal-to-noise pulse distortion ratio (Peak-SNDR) within a 2MHz bandwidth with a sampling rate of 100MHz

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18

Salih, Murat. "Closed-loop joint code delay synchronization and carrier phase recovery for direct-sequence spread spectrum systems." 1996. https://scholarworks.umass.edu/dissertations/AAI9619432.

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We propose a closed-loop system for acquisition of the pseudo-noise (PN) signal in direct-sequence spread-spectrum (DS/SS) systems. We introduce a novel idea of using an auxiliary signal, as opposed to the PN signal itself, for correlation with the incoming signal. The correlation function of the auxiliary signal and the PN signal has a triangle shape that covers essentially the entire period of the PN signal. Consequently, their correlation provides the direction for the phase update of the local signal generator in the acquisition scheme. With coherent demodulation, mean and variance of the acquisition time are derived. Results show that the proposed system acquires the PN phase at least twice faster, with significantly smaller acquisition time variance, than the conventional serial-search acquisition system. We propose a closed-loop system with a pre-loop code phase estimator for acquisition of the PN signal in DS/SS systems. The incoming signal is correlated with the auxiliary signal. The pre-loop code phase estimator uses the correlation result to estimate the incoming code phase. The closed-loop acquisition system starts with this initial estimate. With coherent demodulation, mean and variance of the acquisition time are derived. Results show that, with proper choices of parameters, the proposed system acquires the PN phase significantly faster than both the conventional serial-search system and the closed-loop system without the pre-loop estimator. We propose a closed-loop system for joint acquisition of the carrier phase and the PN signal phase in DS/SS systems. The system has a voltage-controlled-clock loop for PN phase acquisition and a voltage-controlled-oscillator loop for carrier phase acquisition. These loops work together and both loops use the auxiliary signal for correlation with the incoming signal. The correlator outputs provide the directions for the local code phase and the carrier phase updates. Mean and variance of the code phase acquisition time are derived. Results show that, the proposed system performs better than both the noncoherent and the coherent serial-search systems, and almost as good as the coherent closed-loop system.

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19

Knippschild, Clemens Laermann Martin. "Development and implementation of a torque compensation strategy for Lean NOx Trap systems using closed-loop feedback control /." 2007. http://www.gbv.de/dms/ilmenau/abs/543896900knipp.txt.

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20

Jiang, Bo-Qian, and 姜柏阡. "A 6 Gbps Delay-Locked-Loop-Based Clock and Data Recovery Circuit with an Infinite Phase Compensation Technique." Thesis, 2012. http://ndltd.ncl.edu.tw/handle/84813177936174575945.

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碩士
國立中央大學
電機工程學系
101
In recent year, according to the rapid evolution of process and computer network development, the various bandwidth requirement such as short distance like chip-to-chip communication and long distance like fiber-optic communication is increased. The use of serial data transmission substitute for the parallel one. The serial data transmission are widely used for bus in computer such as PCI-Express, SATA, USB, and used for fiber-optic network like SONET. Most of these systems adopted the serial link architecture and operate at gigahertz. This study presents a clock and data recovery (CDR), and takes SATA 6 Gbps specification as reference material. The CDR employs the Delay-Locked Loop (DLL) as data recovery (DR) loop which consists of two sets of complementary voltage-controlled delay line (VCDL). It can solve the problem of delay range limitation. This study presents the CDR circuit fabricated in a 90-nm CMOS process. The dual-loop-based CDR consists of a phase-locked loop (PLL) and a DR loop. Unlike the commonly used PLL-based CDR, the bandwidth for the clock jitter suppression and the specific jitter transfer function (JTF) could be optimized through the PLL and DR loop, respectively. With regard to the DR loop, the DLL could be used for the phase alignment between the input data and the clock signal. However, once the input data accompanies the frequency offset, the DLL may suffer from the limitation of the finite phase tracking range, resulting in the erroneous function. Thus, this study proposes a infinitely phase-compensated DLL (IPDLL), which correlates and swaps the two complementary VCDL if necessary. The IPDLL-based CDR generates the continuous clock phase shifts for data tracking to resolve the operating range limitation of the convenient DLL control scheme. In addition, it exhibits the fast-locking, jitter-peaking-, and jitter-accumulation-free characteristic. As a result, in terms of the CDR setting, conforming that the gain of error signal E(s) of -3 dB lies at the jitter frequency of 4.2±2.1 MHz, the 6-Gb/s input data is simulated with the 3-nH wire bonding, and the RMS and peak-to-peak jitter of the recovered clock are 1.73 ps and 7.77ps, respectively. The chip core area of DR and PLL occupy 0.11 and 0.045 mm2, respectively. The total power consumption is around 79.8 mW at supply of 1.2V.

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21

Tze-YuYu and 余澤佑. "Novel Decentralized Iterative Learning Trackers for the Unknown Sampled-data Interconnected Large-scale State-delay System with Closed-loop Decoupling Property." Thesis, 2010. http://ndltd.ncl.edu.tw/handle/53401450619542839353.

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碩士
國立成功大學
電機工程學系碩博士班
98
The decentralized iterative learning trackers for the unknown sampled-data interconnected large-scale state-delay system consisting of multi-input multi-output subsystems with the closed-loop decoupling property is proposed in this thesis. The off-line observer/Kalman filter identification (OKID) method is used to obtain the decentralized linear models for subsystems in the interconnected large-scale system. In order to get over the effect of modeling error on the identified linear model of each subsystem, an improved observer with the high-gain property based on the digital redesign approach is developed to replace the observer identified by OKID. Then, iterative learning control (ILC) scheme is embedded to the decentralized models. Notice that the convergence of ILC is directly influenced by the initial control input. To accelerate the convergence of ILC, the digital-redesign linear quadratic tracker with the high-gain property is proposed as the initial control input of ILC. The high-gain property controllers can suppress the uncertain errors such as modeling errors, nonlinear perturbations, and external disturbances. Thus, the system output can quickly and accurately track the desired reference in a short time interval with the closed-loop decoupling property.

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22

Wei-CinLiao and 廖偉欽. "Modeling of Decentralized Linear Observers and Trackers for the Unknown Sampled-data Interconnected Large-scale Linear Singular System with Time Delay and Closed-loop Decoupling Property." Thesis, 2010. http://ndltd.ncl.edu.tw/handle/47307280640538143658.

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Анотація:

碩士
國立成功大學
電機工程學系碩博士班
98
Modeling of decentralized linear observers and trackers for the unknown sampled-data interconnected large-scale linear singular system with time delay and closed-loop decoupling property is proposed in this thesis. Through the off-line observer / Kalman filter identification (OKID), the appropriate (low-) order decentralized linear observers with direct transmission terms from input to output for the unknown sampled-data interconnected large-scale linear singular system with time delay are determined. Then, the high-gain linear quadratic suboptimal analogue observer and tracker are proposed based on the each decentralized equivalent regular system with a direct transmission term from input to output. Subsequently, the prediction-based digital redesign method is utilized to obtain practically implemental digital observer and tracker for the sample-data system. With the high-gain property, the decentralized digital-redesign trackers have the decoupling property for the closed-loop interconnected system. Finally, appropriate weighting of the each decentralized observer can be obtained to improve the performance of observer-based tracker by the evolutionary programming (EP).

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23

Yi-HsuanChen and 陳毅玹. "Decentralized Modeling and Linear Observers/Input Constraint Trackers for a More General Class of Unknown Large-scale Interconnected Sampled-data Linear Systems with State Delay and Closed-loop Decoupling Property." Thesis, 2010. http://ndltd.ncl.edu.tw/handle/06494754449861473514.

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Анотація:

碩士
國立成功大學
電機工程學系碩博士班
98
Decentralized modeling and linear observers/input constraint trackers for a more general class of unknown large-scale interconnected sampled-data linear systems with state delay and closed-loop decoupling property are proposed in this thesis. First, the off-line observer/Kalman filter identification (OKID) method is used to determine the appropriate (low-) order decentralized linear observers for the unknown large-scale interconnected sampled-data linear system with state delay. Then, a digital redesign approach with the high-gain property is applied to overcome the modeling error of the above observer effectively. Moreover, a digital-redesign observer-based linear quadratic digital tracker with high-gain property for the sampled-data system is presented, and it provides high performance on trajectory tracking with the closed-loop decoupling property. Finally, to reduce the magnitude of control input, which is caused by the high gain property to fit the requirement of the input constraint, the modified linear quadratic digital tracker (LQDT) is proposed. And the control input can be compressed effectively without losing the original high performance of tracking much.

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24

Heidari, Abdorreza. "Utilizing Channel State Information for Enhancement of Wireless Communication Systems." Thesis, 2007. http://hdl.handle.net/10012/3413.

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One of the fundamental limitations of mobile radio communications is their time-varying fading channel. This thesis addresses the efficient use of channel state information to improve the communication systems, with a particular emphasis on practical issues such as compatibility with the existing wireless systems and low complexity implementation. The closed-loop transmit diversity technique is used to improve the performance of the downlink channel in MIMO communication systems. For example, the WCDMA standard endorsed by 3GPP adopts a mode of downlink closed-loop scheme based on partial channel state information known as mode 1 of 3GPP. Channel state information is fed back from the mobile unit to the base station through a low-rate uncoded feedback bit stream. In these closed-loop systems, feedback error and feedback delay, as well as the sub-optimum reconstruction of the quantized feedback data, are the usual sources of deficiency. In this thesis, we address the efficient reconstruction of the beamforming weights in the presence of the feedback imperfections, by exploiting the residual redundancies in the feedback stream. We propose a number of algorithms for reconstruction of beamforming weights at the base-station, with the constraint of a constant transmit power. The issue of the decoding at the receiver is also addressed. In one of the proposed algorithms, channel fading prediction is utilized to combat the feedback delay. We introduce the concept of Blind Antenna Verification which can substitute the conventional Antenna Weight Verification process without the need for any training data. The closed-loop mode 1 of 3GPP is used as a benchmark, and the performance is examined within a WCDMA simulation framework. It is demonstrated that the proposed algorithms have substantial gain over the conventional method at all mobile speeds, and are suitable for the implementation in practice. The proposed approach is applicable to other closed-loop schemes as well. The problem of (long-range) prediction of the fading channel is also considered, which is a key element for many fading-compensation techniques. A linear approach, usually used to model the time evolution of the fading process, does not perform well for long-range prediction applications. We propose an adaptive algorithm using a state-space approach for the fading process based on the sum-sinusoidal model. Also to enhance the widely-used linear approach, we propose a tracking method for a multi-step linear predictor. Comparing the two methods in our simulations shows that the proposed algorithm significantly outperforms the linear method, for both stationary and non-stationary fading processes, especially for long-range predictions. The robust structure, as well as the reasonable computational complexity, makes the proposed algorithm appealing for practical applications.

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