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This thesis discusses the theory and limitations of a system that has been designed and constructed for the purpose of measuring the phase shift and attenuation of high-frequency (15 MHZ) electromagnetic waves propagating between two insulated antennas that have been lowered down air-filled boreholes (cased with PVC pipe) at San Xavier Mine, Pima County, Arizona. Both the transmitting and receiving antennas are center-fed, sleeve dipoles that have been tuned to approximately their resonant lengths. The insulated-sleeve dipole antenna is modelled as the inner conductor of a radiating, coaxial transmission-line, which allows simple transmission-line formulas to be used in approximating the antenna impedance and current distribution along the antenna. Experimental results at the San Xavier Mine indicate the analogy is valid. Consequently, the most easily interpreted and repeatable measurements have been made with the antennas centered in the borehole.

För att kunna styra en motor krävs bland annat ett tändsystem. Detta tändsystem måste klara av att ge rätt energimängd vid rätt tidpunkt. Mekaniska och tidiga elektroniska tändsystem som konstruerats är inte tillräckligt effektiva. För att få möjlighet till enkel men bättre optimering av effektivitet konstruerades ett kapacitivt tändsystem. Detta system använder en mikrokontroller som beräknar tändfördröjningen. Systemet reglerar tändfördröjningen utifrån en nollpunkt och ett varvtal som detekteras med hjälp av en sensor vid motorns svänghjul. Grundidén är att dela upp systemet i tre delar: laddkrets, tändkrets och styrkort. I ett första steg designades, simulerades och konstruerades varje del för sig. Nästa steg var att sammanfoga dessa tre delar till ett fungerande tändsystem. Resultatet blev ett väl fungerande kapacitivt tändsystem. / An ignition system is needed to control an engine. This ignition system has to be able to provide the right energy at the right time. Due to the lack of efficiency in older mechanical and early electronic systems, we planned to design and construct a capacitive discharge ignition system. This system includes a microcontroller that will calculate the spark timing. The system controls the spark timing depending on the engine speed. The engine speed is measured using a sensor mounted near the engine flywheel. The basic idea is to split the system into three subsystems, the charge subsystem, the ignition subsystem and the controller. The first step was to design, simulate and construct each subsystem. The next step was to merge these subsystems into a working unit. The result was a fully functional capacitive ignition system.

Examensarbetet utfördes för Easygamer i Skoghall vilket är ett företag som bl.a. sysslar med modifiering av de flesta av dagens spelkonsoler samt försäljning av olika datorprodukter. Företaget ville att vi skulle göra om en Xbox till en ”studentdator” som de kallade det. Detta för att man ska kunna få en ganska kraftfull dator för inte så mycket pengar. Med en sådan dator skulle man sedan kunna använda ordbehandlingsprogram, lyssna på musik, surfa på Internet m.m. men självklart också kunna använda Xboxen som en vanlig spelkonsol, om så önskas. / The Degree Project was performed at Easygamer in Skoghall which is a company that among other things modifies most of today’s gaming consoles and sells computer products. They wanted us to transform an Xbox to a “student computer”. You will be able to get a quite powerful computer for not that much money. With this kind of computer you will be able to use “office applications”, listen to music, use the internet etc. But of course, also use the Xbox as a gaming console, if you want to.

In recent years there has been an increased demand for integration of renewable energy into the electricity grid. This has increased research into power converter solutions required to integrate renewable technology into the electricity supply. One such converter is a Cascaded H-Bridge (CHB) Multilevel Converter. Operation of such a topology requires strict control of power flow to ensure that energy is distributed equally across the converters energy storage components. For operation at high power levels, advanced modulation methods may be required to ensure that losses due to non-ideal semiconductor switching are minimised, whilst not compromising the quality of the voltage waveform being produced by the converter. This thesis presents several low switching frequency modulation methods based on Selective Harmonic Elimination (SHE) in order to address these two operational issues. The methods presented involve manipulating the H-Bridge cell voltages of the CHB converter to control power flow. Simulated results are supported by experimental verification from a seven level, single phase CHB converter.

As the deployment of renewable generation increases in the worldwide electrical grids, the development of distributed energy storage becomes more and more of an essential requirement. Energy storage devices connected at Medium Voltage allows for much higher powered deployments and this Ph.D. will focus on the power converter used to interface the energy storage device to the electrical grid. Multi-level converters can be used to provide this interface without huge filtering requirements or the need of a Low Frequency step up transformer. However traditional Multi-level converter topologies require a large number of electrolytic capacitors, reducing the reliability and increasing the cost. Multi-level converters constructed from a Cycloconverter Topology do not require any additional electrolytic capacitors, however the High Frequency transformer, used to provide isolation has to be considerably larger. This Ph.D. will investigate a novel hybrid converter topology to provide an interface between an energy storage device, such as a super-capacitor or battery, to the Medium Voltage grid, designed for high reliability and power density. This topology is called The Hybrid Cycloconverter Topology and is based on a Cycloconverter Topology connected to an auxiliary 3-Phase VSI. A comprehensive simulation study is carried out to investigate the semiconductor losses of this novel converter topology and compared against two alternative topologies. An experimental converter is constructed to validate the theory of operation and to justify its effectiveness.

Voltage source inverter (VSI) is the traditional power converter used to provide variable voltage and frequency from a fixed voltage supply for adjustable speed drive and many other applications. However, the maximum ac output voltage that can be synthesized by a VSI is limited to the available dc-link voltage. With its unique structure, the Z-source inverter can utilise shoot-through states to boost the output voltage and provides an attractive single-stage dc-ac conversion that is able to buck and boost the voltage. For applications with a variable input voltage, this inverter is a very competitive topology. The same concept can equally be extended to the two-stage matrix converter, where a single Z-source network is inserted in its virtual dc-link. The topology formed is, thus, quite straightforward. Its modulation is, however, non-trivial if advantages like voltage buck-boost flexibility, minimum commutation count, ease of implementation, and sinusoidal input and output quantities are to be attained simultaneously. This thesis presents two novel space vector modulation methods for controlling a three-level Z-source neutral point clamped VSI to enable the use of a boost function. The second of the two space vector modulation methods is then adopted and applied to a three-level, two-stage matrix converter with a Z-source network inserted in its virtual dc-link to increase the voltage transfer ratio beyond the intrinsic 86.6\% limit. Simulation results are supported by experimental verification from two laboratory prototype converters.

3D electromagnetic modelling and simulation of various Printed Circuit Board (PCB) components is an important technique for characterizing the Signal Integrity (SI) and Electromagnetic Compatibility (EMC) issues present in a PCB. However, due to limited computational resource and the complexity of the integrated circuits, it is currently not possible to fully model a complete PCB system with 3D electromagnetic solvers. An effort has been made to fully model the PCB with all its components and their S-parameters has been derived so as to integrate these S-parameters in 1D, 2D static or quasi-static field solver or circuit solver tool. The novelty of this thesis is the development and verification of active circuit such as Input and Output buffers and passive channel components such as interconnects, via and connectors and deriving their S-parameters in order to model and characterize the complete PCB using 3D full field solver based on Transmission Line Matrix modelling (TLM) method. An integration of Input/Output (I/O) port in the 3D full field modelling method allows for modelling of the complete PCB system without being computationally expensive. This thesis presents a method for integration of Input/Output port in the 3D time domain modelling environment. Several software tools are available in the market which can characterize these PCBs in the frequency as well as the time domain using 1D, 2D techniques or using circuit solver such as spice. The work in this thesis looks at extending these 1D and 2D techniques for 3D Electromagnetic solvers in the time domain using the TLM technique for PCB analysis. The modelling technique presented in this thesis is based on in-house developed 3D TLM method along with a developed behavioral Integrated Circuit (IC) – macromodel. The method has been applied to a wide variety of PCB topologies along with a range of IC packages to fully validate the approach. The method has also been applied to show the switching effect arising out of the crosstalk in a logic device apart from modelling various discontinuities of PCB interconnects in the form of S11 and S21 parameters. The proposed novel TLM based technique has been selected based on simplification of its approach, electrical equivalence (rather than complex mathematical functions of Maxwell's electromagnetic theory), time domain analysis for transients in a PCB with an increased accuracy over other available methods in the literature. On the experimental side two, four and six layered PCBs with various interconnect discontinuities such as straight line, right angle, fan-out and via and IC packages such as SOT-23 (DBV), SC-70 (DCK) and SOT-553 (DRL) has been designed and manufactured. The modelling results have been verified with the experimental results of these PCBs and other commercial software such as HSPICE, CST design studio available in the market. While characterizing the SI issues, these modelling results can also help in analyzing conducted and radiated EMC/EMI problems to meet various EMC regulations such as CE, FCC around the world.

Interferometry is used in a wide variety of fields for the instrumentation and analysis of subjects and the environment. When light beams interfere, an interference fringe pattern is generated. Captured widefield interference patterns can be used to determine changes in the optical path length of interfering beams across a 2D area. Two interferometer schemes regularly implemented in modern systems include the homodyne interferometer, where light with the same optical frequency in used to generate static intensity fringe patterns, and the heterodyne interferometer, where light with different optical frequencies are used to generate a fringe pattern that is modulated at a frequency equal to the optical frequency difference (beat frequency). A widefield heterodyne system is not straightforward to bring into practice, however, it does offer some benefits over a comparable homodyne interferometer, such as direct phase interpretation and the suppression of low frequency background light in interferograms. In this thesis, a widefield heterodyne interferometer system is presented. A custom prototype modulated light camera (MLC) chip was used to capture both homodyne and heterodyne fringe patterns. The 32x32 pixel camera is capable of continuously demodulating incident modulated light at frequencies between 100kHz and 17MHz. In the presented system, an error in the interferogram phase was determined to be Δφ = ±0.16radians (~9.1º). Comparisons between homodyne and heterodyne interferograms, captured using the MLC, are also presented. With modifications to the system, an ultrastable widefield heterodyne interferometer system was implemented. The intention of this system was to eliminate the contribution of piston phase to a captured interferogram without the need for common path optics. In contrast to the standard heterodyne setup, the reference signal used in the demodulation process was derived from one of the pixels on-board the MLC, rather than from an external source. This new local reference signal tracks the common changes in the temporal phase detected by all the MLC's pixels, eliminating piston phase and substantially reducing the contributions of unwanted vibrations and microphonics from interferograms. To demonstrate this ultrastable system, it is incorporated into a Mach-Zehnder interferometer, where a vibration is induced onto an object arm mirror (using a mounted speaker) at various frequencies. Stable interferograms are captured with the mirror moving at up to 85mm/s at 62Hz (an optical path length of 220μm, or 350 wavelengths for λ = 633nm), however, this limit was the result of the complex motion in the mirror mount rather than the stability limit of the system. The system is shown to be insensitive to pure piston phase variations equivalent to an object velocity of over 3m/s. As an application of the ultrastable system, a novel interferometer has been developed that captures the widefield fringe patterns generated by interfering two independent light sources, rather than by a single split source. The two separately stabilised HeNe lasers, constructed in the laboratory, produce light with a reasonably stable output frequency. Interfering two of these sources produce a heterodyne interference pattern with an unknown beat frequency. The beat frequency continuously varies because of the variation in the output frequency of each laser, but these stabilised lasers produce a beat frequency that drift by as little as 3MHz over 30 minutes. As the ultrastable system tracks changes in the temporal phase and instantaneous frequency of an incident fringe pattern, it can be used to track the variations in the modulation frequency generated by the fluctuations in the two separate lasers. The separation between the two lasers with regards to the images presented was about 35cm, but they can be separated by much larger amounts.

This research deals with optimising a supercapacitor-battery hybrid energy storage system (SB-HESS) to reduce the implementation cost for solar energy applications using the Genetic Algorithm (GA) and the Support Vector Machine (SVM). The integration of a supercapacitor into a battery energy storage system for solar applications is proven to prolong the battery lifespan. Furthermore, the reliability of the system was optimised using a GA within the Taguchi technique in the supercapacitor fabrication process. This is important to reduce the spread in tolerance of supercapacitors values (i.e. capacitance and Equivalent Series Resistance (ESR)) which affect system performance. One of the more important results obtained in this project is the net present cost (NPC) of the Supercapacitor-battery hybrid energy storage system is 7.51% lower than the conventional battery only system over a 20-years project lifetime. This NPC takes into account of components initial capital cost, replacement cost, maintenance and operational cost. The number of batteries is reduced from 40 (conventional – battery only system) to 24 (SB-HESS) with the inclusion of supercapacitors in the system. This leads to reduction cost in the implemented hybrid energy storage system. A greener renewable energy system is achievable as the number of battery is reduced significantly. An optimised combination of the number of components for renewable energy system is also found. The number of batteries is sized, based on the average power output instead of catering to the peak power burst as in a conventional battery only system. This allows for the reduction in the number of batteries as the peak power is catered for by the presence of the supercapacitor. Subsequent efforts have been focused on the energy management system which is coupled with a supervised learning machine – SVM, switches and sensors are used to forecast the load demand beforehand. This load predictive-energy management system is implemented on a lab-scaled hybrid energy storage system prototype. Results obtained also show that this load predictive system allows for accurate load classification and prediction. The supercapacitor in the hybrid energy storage system is able to switch on to cater for peak power without delay. This is crucial in maintaining an optimised battery depth-of-discharge (DOD) in order to reduce the rate of battery damage thru a degradation mechanism which is caused from particular stress factors (especially sulphation on the battery electrode and electrolyte stratification).