Matrix Methods for the Dynamic Range Optimization of Continuous-TimeGm-CFilters

This paper presents a synthesis procedure for the optimization of the dynamic range of continuous-time fully differential G m - C filters. Such procedure builds up on a general extended state-space system representation which provides simple matrix algebra mechanisms to evaluate the noise and distortion performances of filters, as well as, the effect of amplitude and impedance scaling operations. Using these methods, an analytical technique for the dynamic range optimization of weakly nonlinear G m - C filters under power dissipation constraints is presented. The procedure is first explained for general filter structures and then illustrated with a simple biquadratic section

Lithium-Ion Ultracapacitor Energy Storage Integrated with a Variable Speed Wind Turbine for Improved Power Conversion Control

The energy of wind has been increasingly used for electric power generation worldwide due to its availability and ecologically sustainability. Utilization of wind energy in modern power systems creates many technical and economical challenges that need to be addressed for successful large scale wind energy integration. Variations in wind velocity result in variations of output power produced by wind turbines. Variable power output becomes a challenge as the amount of output power of the wind turbines integrated into power systems increases. Large power variations cause voltage and frequency deviations from nominal values that may lead to activation of relay protective equipment, which may result in disconnection of the wind turbines from the grid. Particularly community wind power systems, where only one or a few wind turbines supply loads through a weak grid such as distribution network, are sensitive to supply disturbances. While a majority of power produced in modern power systems comes from synchronous generators that have large inertias and whose control systems can compensate for slow power variations in the system, faster power variations at the scale of fraction of a second to the tens of seconds can seriously reduce reliability of power system operation. Energy storage integrated with wind turbines can address this challenge. In this dissertation, lithium-ion ultracapacitors are investigated as a potential solution for filtering power variations at the scale of tens of seconds. Another class of issues related to utilization of wind energy is related to economical operation of wind energy conversion systems. Wind speed variations create large mechanical loads on wind turbine components, which lead to their early failures. One of the most critical components of a wind turbine is a gearbox that mechanically couples turbine rotor and generator. Gearboxes are exposed to large mechanical load variations which lead to their early failures and increased cost of wind turbine operation and maintenance. This dissertation proposes a new critical load reduction strategy that removes mechanical load components that are the most dangerous in terms of harmful effect they have on a gearbox, resulting in more reliable operation of a wind turbine

Measurements, Models, Systems and Design

531 s.

The monitoring of induction motor starting transients with a view to early fault detection.

The aim of this work is to investigate the possibility of detecting faults in a 3 phase Induction motor by monitoring and analysing the transient line current waveform during the starting period. This is a particularly onerous time for the machine and the inter-relationships between parameters such as current, torque, speed and time are very complex. As a result two parallel paths of investigation have been followed, by methods of experimentation and computer simulation. Transient line current signals have been obtained from purpose built test rigs and these signals have been analysed in both the time and frequency domains. In order to assist with the comprehension of this data a sophisticated computer simulation of the induction motor during the starting period has also been developed. Computer simulation of the induction motor has been developed initially using the two and then three phase induction motor voltage equations which are solved by numerical integration. Using these techniques it has been possible to detect small degrees of fault level for both wound and cage rotor machines by analysing the line current waveform during the starting period. Good agreement has been found between the real and simulated data. A range of Digital Signal Processing techniques have been utilised to extract the components indicative of rotor faults. These techniques were at first wideband and highly numerically intensive, some originating from Speech Processing. The final processing techniques were far simpler and selected by analysis of the results from experimental data, both real and simulated

Digital Filters and Signal Processing

Digital filters, together with signal processing, are being employed in the new technologies and information systems, and are implemented in different areas and applications. Digital filters and signal processing are used with no costs and they can be adapted to different cases with great flexibility and reliability. This book presents advanced developments in digital filters and signal process methods covering different cases studies. They present the main essence of the subject, with the principal approaches to the most recent mathematical models that are being employed worldwide

Unconventional Circuit Elements for Ladder Filter Design

Kmitočtové filtry jsou lineární elektrické obvody, které jsou využívány v různých oblastech elektroniky. Současně tvoří základní stavební bloky pro analogové zpracování signálů. V poslední dekádě bylo zavedeno množství aktivních stavebních bloků pro analogové zpracování signálů. Stále však existuje potřeba vývoje nových aktivních součástek, které by poskytovaly nové možnosti a lepší parametry. V práci jsou diskutovány různé aspekty obvodů pracujících v napěťovém, proudovém a smíšném módu. Práce reaguje na dnešní potřebu nízkovýkonových a nízkonapěťových aplikací pro přenosné přístroje a mobilní komunikační systémy a na problémy jejich návrhu. Potřeba těchto výkonných nízkonapěťových zařízení je výzvou návrhářů k hledání nových obvodových topologií a nových nízkonapěťových technik. V práci je popsána řada aktivních prvků, jako například operační transkonduktanční zesilovač (OTA), proudový konvejor II. generace (CCII) a CDTA (Current Differencing Transconductance Amplifier). Dále jsou navrženy nové prvky, jako jsou VDTA (Voltage Differencing Transconductance Amplifier) a VDVTA (Voltage Differencing Voltage Transconductance Amplifier). Všechny tyto prvky byly rovněž implementovány pomocí "bulk-driven" techniky CMOS s cílem realizace nízkonapěťových aplikací. Tato práce je rovněž zaměřena na náhrady klasických induktorů syntetickými induktory v pasivních LC příčkových filtrech. Tyto náhrady pak mohou vést k syntéze aktivních filtrů se zajímavými vlastnostmi.Frequency filters are linear electric circuits that are used in wide area of electronics. They are also the basic building blocks in analogue signal processing. In the last decade, a huge number of active building blocks for analogue signal processing was introduced. However, there is still the need to develop new active elements that offer new possibilities and better parameters. The current-, voltage-, or mixed-mode analog circuits and their various aspects are discussed in the thesis. This work reflects the trend of low-power (LP) low-voltage (LV) circuits for portable electronic and mobile communication systems and the problems of their design. The need for high-performance LV circuits encourages the analog designers to look for new circuit architectures and new LV techniques. This thesis presents various active elements such as Operational Transconductance Amplifier (OTA), Current Conveyor of Second Generation (CCII), and Current Differencing Transconductance Amplifier (CDTA), and introduces novel ones, such as Voltage Differencing Transconductance Amplifier (VDTA) and Voltage Differencing Voltage Transconductance Amplifier (VDVTA). All the above active elements were also designed in CMOS bulk-driven technology for LP LV applications. This thesis is also focused on replacement of conventional inductors by synthetic ones in passive LC ladder filters. These replacements can lead to the synthesis of active filters with interesting parameters.

Analogue filter networks: developments in theory, design and analyses

Not availabl

Instrumentation of CdZnTe detectors for measuring prompt gamma-rays emitted during particle therapy

Background: The irradiation of cancer patients with charged particles, mainly protons and carbon ions, has become an established method for the treatment of specific types of tumors. In comparison with the use of X-rays or gamma-rays, particle therapy has the advantage that the dose distribution in the patient can be precisely controlled. Tissue or organs lying near the tumor will be spared. A verification of the treatment plan with the actual dose deposition by means of a measurement can be done through range assessment of the particle beam. For this purpose, prompt gamma-rays are detected, which are emitted by the affected target volume during irradiation. Motivation: The detection of prompt gamma-rays is a task related to radiation detection and measurement. Nuclear applications in medicine can be found in particular for in vivo diagnosis. In that respect the spatially resolved measurement of gamma-rays is an essential technique for nuclear imaging, however, technical requirements of radiation measurement during particle therapy are much more challenging than those of classical applications. For this purpose, appropriate instruments beyond the state-of-the-art need to be developed and tested for detecting prompt gamma-rays. Hence the success of a method for range assessment of particle beams is largely determined by the implementation of electronics. In practice, this means that a suitable detector material with adapted readout electronics, signal and information processing, and data interface must be utilized to solve the challenges. Thus, the parameters of the system (e.g. segmentation, time or energy resolution) can be optimized depending on the method (e.g. slit camera, time-of-flight measurement or Compton camera). Regardless of the method, the detector system must have a high count rate capability and a large measuring range (>7 MeV). For a subsequent evaluation of a suitable method for imaging, the mentioned parameters may not be restricted by the electronics. Digital signal processing is predestined for multipurpose tasks, and, in terms of the demands made, the performance of such an implementation has to be determined. Materials and methods: In this study, the instrumentation of a detector system for prompt gamma-rays emitted during particle therapy is limited to the use of a cadmium zinc telluride (CdZnTe, CZT) semiconductor detector. The detector crystal is divided into an 8x8 pixel array by segmented electrodes. Analog and digital signal processing are exemplarily tested with this type of detector and aims for application of a Compton camera to range assessment. The electronics are implemented with commercial off-the-shelf (COTS) components. If applicable, functional units of the detector system were digitalized and implemented in a field-programmable gate array (FPGA). An efficient implementation of the algorithms in terms of timing and logic utilization is fundamental to the design of digital circuits. The measurement system is characterized with radioactive sources to determine the measurement dynamic range and resolution. Finally, the performance is examined in terms of the requirements of particle therapy with experiments at particle accelerators. Results: A detector system based on a CZT pixel detector has been developed and tested. Although the use of an application-specific integrated circuit is convenient, this approach was rejected because there was no circuit available which met the requirements. Instead, a multichannel, compact, and low-noise analog amplifier circuit with COTS components has been implemented. Finally, the 65 information channels of a detector are digitized, processed and visualized. An advanced digital signal processing transforms the traditional approaches of nuclear electronics in algorithms and digital filter structures for an FPGA. With regard to the characteristic signals (e.g. varying rise times, depth-dependent energy measurement) of a CZT pixel detector, it could be shown that digital pulse processing results in a very good energy resolution (~2% FWHM at 511 keV), as well as permits a time measurement in the range of some tens of nanoseconds. Furthermore, the experimental results have shown that the dynamic range of the detector system could be significantly improved compared to the existing prototype of the Compton camera (~10 keV..7 MeV). Even count rates of ~100 kcps in a high-energy beam could be ultimately processed with the CZT pixel detector. But this is merely a limit of the detector due to its volume, and not related to electronics. In addition, the versatility of digital signal processing has been demonstrated with other detector materials (e.g. CeBr3). With foresight on high data throughput in a distributed data acquisition from multiple detectors, a Gigabit Ethernet link has been implemented as data interface. Conclusions: To fully exploit the capabilities of a CZT pixel detector, a digital signal processing is absolutely necessary. A decisive advantage of the digital approach is the ease of use in a multichannel system. Thus with digitalization, a necessary step has been done to master the complexity of a Compton camera. Furthermore, the benchmark of technology shows that a CZT pixel detector withstands the requirements of measuring prompt gamma-rays during particle therapy. The previously used orthogonal strip detector must be replaced by the pixel detector in favor of increased efficiency and improved energy resolution. With the integration of the developed digital detector system into a Compton camera, it must be ultimately proven whether this method is applicable for range assessment in particle therapy. Even if another method is more convenient in a clinical environment due to practical considerations, the detector system of that method may benefit from the shown instrumentation of a digital signal processing system for nuclear applications.:1. Introduction 1.1. Aim of this work 2. Analog front-end electronics 2.1. State-of-the-art 2.2. Basic design considerations 2.2.1. CZT detector assembly 2.2.2. Electrical characteristics of a CZT pixel detector 2.2.3. High voltage biasing and grounding 2.2.4. Signal formation in CZT detectors 2.2.5. Readout concepts 2.2.6. Operational amplifier 2.3. Circuit design of a charge-sensitive amplifier 2.3.1. Circuit analysis 2.3.2. Charge-to-voltage transfer function 2.3.3. Input coupling of the CSA 2.3.4. Noise 2.4. Implementation and Test 2.5. Results 2.5.1. Test pulse input 2.5.2. Pixel detector 2.6. Conclusion 3. Digital signal processing 3.1. Unfolding-synthesis technique 3.2. Digital deconvolution 3.2.1. Prior work 3.2.2. Discrete-time inverse amplifier transfer function 3.2.3. Application to measured signals 3.2.4. Implementation of a higher order IIR filter 3.2.5. Conclusion 3.3. Digital pulse synthesis 3.3.1. Prior work 3.3.2. FIR filter structures for FPGAs 3.3.3. Optimized fixed-point arithmetic 3.3.4. Conclusion 4. Data interface 4.1. State-of-the-art 4.2. Embedded Gigabit Ethernet protocol stack 4.3. Implementation 4.3.1. System overview 4.3.2. Media Access Control 4.3.3. Embedded protocol stack 4.3.4. Clock synchronization 4.4. Measurements and results 4.4.1. Throughput performance 4.4.2. Synchronization 4.4.3. Resource utilization 4.5. Conclusion 5. Experimental results 5.1. Digital pulse shapers 5.1.1. Spectroscopy application 5.1.2. Timing applications 5.2. Gamma-ray spectroscopy 5.2.1. Energy resolution of scintillation detectors 5.2.2. Energy resolution of a CZT pixel detector 5.3. Gamma-ray timing 5.3.1. Timing performance of scintillation detectors 5.3.2. Timing performance of CZT pixel detectors 5.4. Measurements with a particle beam 5.4.1. Bremsstrahlung Facility at ELBE 6. Discussion 7. Summary 8. ZusammenfassungHintergrund: Die Bestrahlung von Krebspatienten mit geladenen Teilchen, vor allem Protonen oder Kohlenstoffionen, ist mittlerweile eine etablierte Methode zur Behandlung von speziellen Tumorarten. Im Vergleich mit der Anwendung von Röntgen- oder Gammastrahlen hat die Teilchentherapie den Vorteil, dass die Dosisverteilung im Patienten präziser gesteuert werden kann. Dadurch werden um den Tumor liegendes Gewebe oder Organe geschont. Die messtechnische Verifikation des Bestrahlungsplans mit der tatsächlichen Dosisdeposition kann über eine Reichweitenkontrolle des Teilchenstrahls erfolgen. Für diesen Zweck werden prompte Gammastrahlen detektiert, die während der Bestrahlung vom getroffenen Zielvolumen emittiert werden. Fragestellung: Die Detektion von prompten Gammastrahlen ist eine Aufgabenstellung der Strahlenmesstechnik. Strahlenanwendungen in der Medizintechnik finden sich insbesondere in der in-vivo Diagnostik. Dabei ist die räumlich aufgelöste Messung von Gammastrahlen bereits zentraler Bestandteil der nuklearmedizinischen Bildgebung, jedoch sind die technischen Anforderungen der Strahlendetektion während der Teilchentherapie im Vergleich mit klassischen Anwendungen weitaus anspruchsvoller. Über den Stand der Technik hinaus müssen für diesen Zweck geeignete Instrumente zur Erfassung der prompten Gammastrahlen entwickelt und erprobt werden. Die elektrotechnische Realisierung bestimmt maßgeblich den Erfolg eines Verfahrens zur Reichweitenkontrolle von Teilchenstrahlen. Konkret bedeutet dies, dass ein geeignetes Detektormaterial mit angepasster Ausleseelektronik, Signal- und Informationsverarbeitung sowie Datenschnittstelle zur Problemlösung eingesetzt werden muss. Damit können die Parameter des Systems (z. B. Segmentierung, Zeit- oder Energieauflösung) in Abhängigkeit der Methode (z.B. Schlitzkamera, Flugzeitmessung oder Compton-Kamera) optimiert werden. Unabhängig vom Verfahren muss das Detektorsystem eine hohe Ratenfestigkeit und einen großen Messbereich (>7 MeV) besitzen. Für die anschließende Evaluierung eines geeigneten Verfahrens zur Bildgebung dürfen die genannten Parameter durch die Elektronik nicht eingeschränkt werden. Eine digitale Signalverarbeitung ist für universelle Aufgaben prädestiniert und die Leistungsfähigkeit einer solchen Implementierung soll hinsichtlich der gestellten Anforderungen bestimmt werden. Material und Methode: Die Instrumentierung eines Detektorsystems für prompte Gammastrahlen beschränkt sich in dieser Arbeit auf die Anwendung eines Cadmiumzinktellurid (CdZnTe, CZT) Halbleiterdetektors. Der Detektorkristall ist durch segmentierte Elektroden in ein 8x8 Pixelarray geteilt. Die analoge und digitale Signalverarbeitung wird beispielhaft mit diesem Detektortyp erprobt und zielt auf die Anwendung zur Reichweitenkontrolle mit einer Compton-Kamera. Die Elektronik wird mit seriengefertigten integrierten Schaltkreisen umgesetzt. Soweit möglich, werden die Funktionseinheiten des Detektorsystems digitalisiert und in einem field-programmable gate array (FPGA) implementiert. Eine effiziente Umsetzung der Algorithmen in Bezug auf Zeitverhalten und Logikverbrauch ist grundlegend für den Entwurf der digitalen Schaltungen. Das Messsystem wird mit radioaktiven Prüfstrahlern hinsichtlich Messbereichsdynamik und Auflösung charakterisiert. Schließlich wird die Leistungsfähigkeit hinsichtlich der Anforderungen der Teilchentherapie mit Experimenten am Teilchenbeschleuniger untersucht. Ergebnisse: Es wurde ein Detektorsystem auf Basis von CZT Pixeldetektoren entwickelt und erprobt. Obwohl der Einsatz einer anwendungsspezifischen integrierten Schaltung zweckmäßig wäre, wurde dieser Ansatz zurückgewiesen, da kein verfügbarer Schaltkreis die Anforderungen erfüllte. Stattdessen wurde eine vielkanalige, kompakte und rauscharme analoge Verstärkerschaltung mit seriengefertigten integrierten Schaltkreisen aufgebaut. Letztendlich werden die 65 Informationskanäle eines Detektors digitalisiert, verarbeitet und visualisiert. Eine fortschrittliche digitale Signalverarbeitung überführt die traditionellen Ansätze der Nuklearelektronik in Algorithmen und digitale Filterstrukturen für einen FPGA. Es konnte gezeigt werden, dass die digitale Pulsverarbeitung in Bezug auf die charakteristischen Signale (u.a. variierende Anstiegszeiten, tiefenabhängige Energiemessung) eines CZT Pixeldetektors eine sehr gute Energieauflösung (~2% FWHM at 511 keV) sowie eine Zeitmessung im Bereich von einigen 10 ns ermöglicht. Weiterhin haben die experimentellen Ergebnisse gezeigt, dass der Dynamikbereich des Detektorsystems im Vergleich zum bestehenden Prototyp der Compton-Kamera deutlich verbessert werden konnte (~10 keV..7 MeV). Nach allem konnten auch Zählraten von >100 kcps in einem hochenergetischen Strahl mit dem CZT Pixeldetektor verarbeitet werden. Dies stellt aber lediglich eine Begrenzung des Detektors aufgrund seines Volumens, nicht jedoch der Elektronik, dar. Zudem wurde die Vielseitigkeit der digitalen Signalverarbeitung auch mit anderen Detektormaterialen (u.a. CeBr3) demonstriert. Mit Voraussicht auf einen hohen Datendurchsatz in einer verteilten Datenerfassung von mehreren Detektoren, wurde als Datenschnittstelle eine Gigabit Ethernet Verbindung implementiert. Schlussfolgerung: Um die Leistungsfähigkeit eines CZT Pixeldetektors vollständig auszunutzen, ist eine digitale Signalverarbeitung zwingend notwendig. Ein entscheidender Vorteil des digitalen Ansatzes ist die einfache Handhabbarkeit in einem vielkanaligen System. Mit der Digitalisierung wurde ein notwendiger Schritt getan, um die Komplexität einer Compton-Kamera beherrschbar zu machen. Weiterhin zeigt die Technologiebewertung, dass ein CZT Pixeldetektor den Anforderungen der Teilchentherapie für die Messung prompter Gammastrahlen stand hält. Der bisher eingesetzte Streifendetektor muss zugunsten einer gesteigerten Effizienz und verbesserter Energieauflösung durch den Pixeldetektor ersetzt werden. Mit der Integration des entwickelten digitalen Detektorsystems in eine Compton-Kamera muss abschließend geprüft werden, ob dieses Verfahren für die Reichweitenkontrolle in der Teilchentherapie anwendbar ist. Auch wenn sich herausstellt, dass ein anderes Verfahren unter klinischen Bedingungen praktikabler ist, so kann auch dieses Detektorsystem von der gezeigten Instrumentierung eines digitalen Signalverarbeitungssystems profitieren.:1. Introduction 1.1. Aim of this work 2. Analog front-end electronics 2.1. State-of-the-art 2.2. Basic design considerations 2.2.1. CZT detector assembly 2.2.2. Electrical characteristics of a CZT pixel detector 2.2.3. High voltage biasing and grounding 2.2.4. Signal formation in CZT detectors 2.2.5. Readout concepts 2.2.6. Operational amplifier 2.3. Circuit design of a charge-sensitive amplifier 2.3.1. Circuit analysis 2.3.2. Charge-to-voltage transfer function 2.3.3. Input coupling of the CSA 2.3.4. Noise 2.4. Implementation and Test 2.5. Results 2.5.1. Test pulse input 2.5.2. Pixel detector 2.6. Conclusion 3. Digital signal processing 3.1. Unfolding-synthesis technique 3.2. Digital deconvolution 3.2.1. Prior work 3.2.2. Discrete-time inverse amplifier transfer function 3.2.3. Application to measured signals 3.2.4. Implementation of a higher order IIR filter 3.2.5. Conclusion 3.3. Digital pulse synthesis 3.3.1. Prior work 3.3.2. FIR filter structures for FPGAs 3.3.3. Optimized fixed-point arithmetic 3.3.4. Conclusion 4. Data interface 4.1. State-of-the-art 4.2. Embedded Gigabit Ethernet protocol stack 4.3. Implementation 4.3.1. System overview 4.3.2. Media Access Control 4.3.3. Embedded protocol stack 4.3.4. Clock synchronization 4.4. Measurements and results 4.4.1. Throughput performance 4.4.2. Synchronization 4.4.3. Resource utilization 4.5. Conclusion 5. Experimental results 5.1. Digital pulse shapers 5.1.1. Spectroscopy application 5.1.2. Timing applications 5.2. Gamma-ray spectroscopy 5.2.1. Energy resolution of scintillation detectors 5.2.2. Energy resolution of a CZT pixel detector 5.3. Gamma-ray timing 5.3.1. Timing performance of scintillation detectors 5.3.2. Timing performance of CZT pixel detectors 5.4. Measurements with a particle beam 5.4.1. Bremsstrahlung Facility at ELBE 6. Discussion 7. Summary 8. Zusammenfassun

Wind Power

This book is the result of inspirations and contributions from many researchers of different fields. A wide verity of research results are merged together to make this book useful for students and researchers who will take contribution for further development of the existing technology. I hope you will enjoy the book, so that my effort to bringing it together for you will be successful. In my capacity, as the Editor of this book, I would like to thanks and appreciate the chapter authors, who ensured the quality of the material as well as submitting their best works. Most of the results presented in to the book have already been published on international journals and appreciated in many international conferences

The development of a rule based expert system to automate the digital analysis of condition monitoring parameters captured on rolling element bearings subjected to simulated failure

This synopsis provides a brief summary of the development of a rule based expert system to diagnose bearing failure. Firstly it covers the proposal of a generic, expert system based industrial condition monitoring system. It then discusses in more detail the development of a specific aspect ofthe system, viz. the analysis of rolling element bearing condition. The bearing test rig and data capture system are described, followed by primary research to define the bearing analysis solution space. This includes the use of vibration parameters, measured and derived operating conditions and the bearing running condition. It then explains the development of rulebases for the three analysis tasks of detection, diagnosis and prognosis. Included is a discussion on techniques used to normalise and adjust the vibration parameters to allow analysis under any operating conditions. Finally the synopsis is concluded with a discussion on the performance of the system and contributions made to the developing field of condition monitoring using expert systems