Intensive development in the field of high-temperature superconductors (HTS) has resulted in long length HTS with high current carrying capacity. The performance of HTS in the form of multifilamentary silver sheathed Bi-2223 tapes is close to the requirements for power application. Several power apparatus prototypes based on HTS have been and are being demonstrated. Recently the first commercial order for a HTS power apparatus was placed. Tennessee Valley Authority ordered two 12 MVA synchronous condensers with HTS rotor windings for reactive power compensation. In most power devices the conductor is carrying an AC transport current while it is exposed to an AC magnetic field transverse to the current path. In certain applications such as multi-layer power transmission cables or the control winding in a controllable reactor, the conductors are exposed to a magnetic field component longitudinal to the tape axis that is parallel with the current path. In this thesis, the losses in HTS tapes in longitudinally applied magnetic field are investigated and a single phase small scale controllable reactor with a loss optimized HTS control winding is designed, constructed and tested. An experimental setup to measure the losses in tapes exposed to longitudinal magnetic fields, transport currents, frequencies, and temperatures is presented. The system is based on a calorimetric loss measuring method where the losses are determined by the temperature response of the conductor when exposed to magnetic field and/or carrying transport current. Semi-empirical loss models are developed from the results of the loss measurements of non-twisted multifilamentary Bi-2223 tapes. The losses when the sample is carrying transport currents and is exposed to longitudinal magnetic fields are found to consist of hysteresis, flux flow, and eddy current losses. The hysteresis losses can be modeled with the critical state model. The flux flow losses can be described with a power law dependent current voltage characteristic. The loss models are well suited for the design of power devices in which HTS is exposed to longitudinal magnetic fields. Based on the knowledge of the losses a single phase small scale controllable reactor with a loss optimized HTS control winding is designed, constructed and tested. A simple model of the magnetic circuit of the controllable reactor is presented. Calculations from the model are compared with experimental measurements. The feasibility to design controllable shunt reactors with large linear dynamic range, low losses and limited harmonic distortion is demonstrated. Compared to a copper control winding the HTS control winding increases the dynamic range and reduces the size due to the high current density and reduces the losses of the control winding. / <p>QC 20100927</p>

<p>Detta är ett examensarbete som handlar om bytet av värmesystem i Glömminge Kyrka på Öland. Glömminge kyrka har bytt ut sitt gamla värmesystem som gick på direktverkande el mot ett mer kostnadseffektivt och miljöanpassat värmesystem. Det nya systemet har brännare med panna för att kunna värma kyrkan med olika sorters miljöbränslen exempelvis rapsfettsyra. I arbetet beskrivs värmesystemet, bränsletyper samt det styrsystem som används för att styra värmesystemet. Examensarbetet handlar även om vilka nivåer av relativ luftfuktighet man bör ha i byggnader med känsliga inventarier och vilka åtgärder man kan vidta för att hålla önskad luftfuktighet.</p>

One third of Sweden's energy use is used by residential and commercial buildings, of which nearly 60 % go to heating. Opportunities are great for using energy more efficiently and there is a great potential to save energy by improving the construction of the building. The EU places higher demands on energy use and means that monitoring of energy use is becoming increasingly important. From 2021, all new production of buildings in EU Member States will be "close to zero energy houses". The definition of "near zero energy house" has not yet been established in Sweden, but in a throw-out of BBR is the requirement to tighten by 40 % discussed. Efforts to get more energy-efficient buildings are under way and are being carried out in close collaboration with BBR.   This degree project has been carried out on behalf of Skebo, where the goal is to establish the real specific energy use in operation for two properties in Skellefteå, Ringduvan and Odenskrapan. Compare and analyze deviations from projected specific energy use. Ringduvan was ready for occupation in spring 2014 and Odenskrapan in early 2016.Both buildings have electricity and district heating from Skellefteå Kraft. Ringduvan is projected by NCC and Oden of Lindbergs Energi &amp; VVS AB.   Sveby ("Standardize and Verify Energy Performance in Buildings") is a development program run by actors in the construction and real estate industry. Svebys aim is to develop an industry standard that increases the accuracy of the project between projected and real energy use. With increased knowledge of user-related use, a standardized approach, energy monitoring and enhanced cooperation between actors, the goal is to reduce the deviations. Operators in the industry may choose to enter into a Sveby agreement, which includes a common method of procurement, design and verification.   The projected specific energy use for Ringduvan is 76 kWh/m2,year and the real is 101 kWh/m2,year. Odenskrapan projected is 53 kWh/m2,year and the real is 93 kWh/ m2,year. That is, the specific energy use exceeds the estimated energy consumption by 33 % for Ringduvan and 75 % for Odenskrapan. This means that much more district heating and real estate is needed than expected.   In general, potential causes of higher energy use have been identified. But nothing has been confirmed and more work is required against the buildings in order to compare and identify the exact reasons.

Following an ongoing change towards an increasingly renewable power generation system Swedish grid operators are facing several challenges in coming years. As authorities plan for the decommissioning of nuclear power an increased reliance on de-centralised energy sources such as photo-voltaic distributed generation (PVDG) is expected. A technology observed in some cases to accompany local power quality issues severe enough to impose grid expansion measures from distribution system operators (DSOs). Considering a combination of an indicative utilisation inefficiency of classical grid expansion measures and a recent year maturing of various energy storage technologies, this report sets out to evaluate the possibility of utilising centralised energy storage systems (ESSs) for deferment of classical grid expansion measures. For the purpose of identifying the most prominent problem scenarios of modern production- and consumption behaviours as well as the possible solutions offered by centralised ESSs, a literature review of journal articles and technical reports was conducted in combination with a case-study of an existing urban grid operated by Umeå Energi Elnät AB (UEEN). The work regarding ESSs is directed with specific focus towards evaluating which ESS services can potentially facilitate grid expansion deferment and what ESS placement is advisable for efficient utilisation. Assessing possible grid safety implications, potential for peak load shaving and the presently most suitable energy storage technology was also within the scope of the study. The literature review reveals PVDG induced feeder line over-voltage and transformer overload the most likely and previously observed implications imposing grid expansion measures. The former more prominent in elongated, typically rural, grids and the latter in more densely populated urban grids. For deferment of over-voltage related grid expansion measures a centralised ESS can be utilised for voltage support provided placement is made close to the affected grid section, presumably far out the affected feeder line. This result is coherent throughout the reviewed literature and is supported by the results of the case-study. Distribution transformer overload and its imposed grid expansion measures can be deferred through load re-allocation and peak load shaving, two services proven achievable by centralised ESSs and the capacity for which increases if ESS placement is made closer the distribution transformer. Provided present regulatory and standards are adhered to upon installation, significant negative impact of centralised ESSs on distribution grid safety can be avoided. Most energy storage technologies, including battery based energy storage technologies indicated from the literature review providing the most suitable characteristics for use in centralised distribution grid ESSs, utilise well established systems for grid connection hence no presently unsolvable grid safety implications are identified. Technical reports of real applications of centralised ESSs reinforce this argument as successful implementation without ESS caused grid safety implications have been achieved in the Swedish distribution grid in the past.

No description available.

The success of modern electronics is built on the possibility to accurately predict system behavior by the use of simulation tools. This paradigm can be extended to components such as sensors attached to the electronics. The ability to simulate both sensors (mechanical components) and electronics together renders possible effective optimizations at system level, i.e. minimizing size, cost and power consumption. In this thesis the simulation of a combined electronics and ultrasound sensor system is explored. The environment used is compatible with the electronic simulation tool SPICE. Improvements and verifications of existing SPICE models for ultrasound equipment is described, and applied in the design of integrated analog electronics for an ultrasound measurement system. Emphasis is put on the interdependence between acoustic performance and electronics design. The goal is to improve precision in the simulations to a level where real systems can be implemented from simulation results alone. The thesis is divided into introduction and three attached papers. In the introduction, an overview of ultrasound devices, measurement technology and simulation is given. Tools and design flow for analog integrated circuits are discussed. The first paper shows that system simulations can be used to minimize the size of the transistors used to excite an ultrasound transducer, while keeping maximum output ultrasound energy. A design of an ASIC (Application Specific Integrated Circuit) driver stage for piezoelectric crystals is made and performance of the system is predicted using system simulations. Measurements and simulations are compared, showing that the optimum transistor size can be chosen from simulation data with very good precision. The goal with paper number two is to achieve absolute amplitude correctness in PSpice simulations of ultrasonic systems. Previously published models of the ultrasound propagation medium include viscoelastic loss but disregard loss due to diffraction, i.e. beam spreading. This paper presents a method to include diffraction loss in the models. Measurements and simulations have been performed using a pulse echo system in water. Results show that the simulated amplitude of the returned echo differs less than 10% from measured values in both near and far fields. In paper number three, the influence of parasitic electrical components on measurements and simulations is investigated. It is shown that simulation of excitation pulses can be done with very high accuracy if parasitics are taken into account. The coaxial cable which connects the electronics and the transducer represents one of the major parasitic components in the system. As the cable length is varied, pulse echo amplitudes and time delays shift. It is shown that simulations can be used to predict these effects with good accuracy. / Godkänd; 2001; 20070313 (ysko)

From an early age, people display the ability to quickly and effortlessly interpret the orientation and movement of human body parts, thereby allowing one to infer the intentions of others who are nearby and to comprehend an important nonverbal form of communication. The ease with which one accomplishes this task belies the difficulty of a problem that has challenged computational systems for decades, human motion analysis. Technological developments over years have resulted into many systems for measuring body segment positions and angles between segments. In these systems human body is typically considered as a system of rigid links connected by joints. The motion is estimated by the use of measurements from mechanical, optical, magnetic, or inertial trackers. Among all kinds of sensors, optical sensing encompasses a large and varying collection of technologies. In a computer vision context, human motion analysis is a topic that studies methods and applications in which two or more consecutive images from an image sequences, e.g. captured by a video camera, are processed to produce information based on the apparent human body motion in the images. Many different disciplines employ motion analysis systems to capture movement and posture of human body for applications such as medical diagnostics, virtual reality, human-computer interaction etc. This thesis gives an insight into the state of the art human motion analysissystems, and provides new methods for capturing human motion.

The ATLAS-upgrade is a project with the endeavors to enhance the performance of the ATLAS detector located at CERN. The intention of this project is to enable testing of the upgraded components locally at Ångströmlaboratoriet, Uppsala University, in cooperation with CERN. A power supply system  was constructed to provide the correct voltage to the new electronic hybrid circuits. The hybrids need to be tested under the right conditions hence governing the features of the system. A graphical user interface with included software that controls and monitors the hardware in the system was developed. To ease connection of the test system, a backplane power circuit board was designed for the power supply cards. / ATLAS-upgrade experiment

With laser Doppler flowmetry, blood flow can be measured in the smallest blood vessels in the body. Perimed AB is a company that develops instruments for microvascular diagnostics and want to develop a 15-mm probe with laser Doppler and heater. By using a new component, a combined VCSEL and photodetector from Kyocera, a prototype for the 15-mm probe is designed to measure blood flow. The results show that the signal is sufficient for optical analysis. Further work is necessary to determine if the 15-mm probe can be realized.

This Master Thesis studies the different quantization effects in hardware architecture due to the use of finite word lenght. This master thesis gives a deterministic analysis with relation to the accuracy and presents a relationship between input bits and coefficient bits for minimizing recourses and to obtained the best relation with the accuracy. Furthermore, the objective of this mater thesis is to find a direct relation between the input bits and coefficient bits. This can be used as guide for the design of FFT hardware architectures