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This thesis describes the development of several small signal analysis methods for the modelling of power electronic converters. The methods are written generally and are intended to be able to be applied to all converter classes. In the penultimate chapter these general models are used to model the capacitor commutated converter. All the contained methods are based around a time domain small signal model. This time domain small model is a linearization of a power electronic system of passive components and ideal switches described as a hybrid system. The key problem in the derivation of the small signal model is the correct determination and description of the linearized effect of switching instant variation. Three analysis methods based upon the small signal model are advanced in this thesis, these are; time domain sensitivity matrices for use in a Newton determination of the cyclic steady state of a power electronic converter, partial waveform construction of harmonic sensitivity matrices for studying sensitivity of converters to harmonic disturbances, and harmonic state space models also for the construction of harmonic sensitivity matrices and for study of dynamic systems. Each modelling technique is applied to the more common converter topologies of the Buck-Boost converter and the Graetz Bridge before being finally applied to the capacitor commutated converter. Each technique is compared to PSCAD-EMTDC simulations for verification.

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The most commonly used method for the time-domain Maxwell equations is the Finite-Difference Time-Domain method (FDTD). This is an explicit, second-order accurate method, which is used on a staggered Cartesian grid. The main drawback with the FDTD method is its inability to accurately model curved objects and small geometrical features. This is due to the Cartesian grid, which leads to a staircase approximation of the geometry and small details are not resolved at all. This thesis presents different ways to circumvent this drawback, but still take advantage of the benefits of the FDTD method. An approach to avoid staircasing errors but still retain the efficiency of the FDTD method is to use a hybrid grid. A few layers of unstructured cells are used close to curved objects and a Cartesian grid is used for the rest of the domain. For the choice of solver on the unstructured grid two different alternatives are compared: an explicit Finite-Volume Time-Domain (FVTD) solver and an implicit Finite-Element Time-Domain (FETD) solver. The hybrid solvers calculate the scattering from complex objects much more efficiently compared to using FDTD on highly resolved Cartesian grids. For the same accuracy in the solution roughly a factor of 10 in memory requirements and a factor of 20 in execution time are gained. The ability to model features that are small relative to the cell size is often important in electromagnetic simulations. In this thesis a technique to generalize a well-known subcell model for thin wires, in order to take arbitrarily oriented wires in FETD and FDTD into account, is proposed. The method gives considerable modeling flexibility compared to earlier methods and is proven stable. The results show excellent consistency and very good accuracy on different antenna configurations. The recursive convolution method is often used to model frequency dispersive materials in FDTD. This method is used to enable modeling of such materials in the unstructured FVTD and FETD solvers. The stability of both solvers is analyzed and their accuracy is demonstrated by computing the radar cross section for homogeneous as well as layered spheres with frequency dependent permittivity.

In this thesis, a method of distortion analysis of electromagnetic field sensors using orthogonal polynomial subspaces is presented. The effective height of the sensor is viewed as the impulse response of a linear system. The impulse response corresponds to a linear transformation which maps every electromagnetic incident field waveform to a received voltage waveform. Hermite and Laguerre orthogonal polynomials are used as the basis sets for the subspace of incident electromagnetic field waveforms. Using the selected basis set, a transformation matrix is calculated for the sensors. The transformation matrices are compared to a reference transformation matrix as a measure of distortion. The transformation matrices can describe the sensor behavior up to a certain frequency range. The limits on this frequency range are investigated for both Hermite-Gauss and Laguerre functions. The unique property of Laguerre functions is used to prove that the transformation matrix has a particular pattern. This method is applied on case studied sensors both in computer simulation and measurements.

An essential component for evaluating the performance of a mine site after its closure includes the tracking of water movement through mine waste such as tailings and overburden. A critical element of this evaluation is the measurement of the volume of water stored in the closure landform. The objective of this project was to design a time domain reflectometry (TDR) device that could be used to measure the volumetric water content of a soil profile to depths of 10 to 20 m. Upon completion of this project, the device will be integrated onto ConeTec’s cone penetration testing (CPT) shaft for initially monitoring Syncrude Canada Limited’s northeastern Alberta oil sands mine site. The objective of this project will be achieved through at least two phases of research and development; this thesis concentrates on the first phase. In this phase, research focused on prototype development through laboratory testing to determine appropriate TDR probe geometries and configurations that could be integrated onto a CPT shaft. Considerations also had to be made for protecting the integrity of the probe during field use and mitigating the effects of highly electrically conductive soils common in reclaimed mine sites. A number of different prototype designs were initially investigated in this research, leading to the development of a refined prototype for advanced testing. Testing for the project was carried out first in solutions of known dielectric constants and salinities, and then proceeded to soils with a range of known water contents and salinities. Good quality electrical connections were found to be crucial for generating waveforms that were easy to interpret; bad connections resulted in poor results in a number of cases. Decreased probe sensitivity was observed in response to increased rod embedment within the probe variants. A far greater decrease in sensitivity was seen in the results of the fully sheathed rods, although the sheathing was effective for extending the range of the probe in electrically conductive testing conditions. Despite poor results that were seen in some of the tests, overall the results were promising. In particular, results from the push-test showed that the probe was able to monitor changes in water content with depth.

Microfluidic techniques have allowed for fast, sensitive, and low cost applications of the Polymerase Chain Reaction (PCR) through the use of small reaction volumes, rapid amplification speeds, and the on-chip integration of upstream and downstream sample handling processes including purification and electrophoretic separation functionality. While such systems are capable of measuring the expression levels of thousands of genes simultaneously, or in hundreds of cells, or with sample-in and answer-out capability, none of these systems are easily scalable in the time domain. Because of this, the field of gene expression measurement has yet to fully utilize the advantages of microfluidic PCR in developing systems to measure changes in gene expression in increments of hours rather than days. In this project, we developed a microfluidic RT-qPCR system that utilizes infrared heating and open-loop control to reliably reverse transcribe, amplify, and detect samples in a single 1 μl polymer chip. Optimized power profiles were created that allow for fast heating and cooling rates while minimizing undershoot and overshoot from the desired hold temperatures. By utilizing repeatable microfluidic chip manufacturing techniques, and by controlling the environment around the chip, the same open loop program can repeatedly amplify multiple samples without any need for temperature feedback or recalibration between runs. Furthermore, the system was designed to operate on top of a fluorescence microscope to enable real-time fluorescence detection and quantification of starting copy number. By eliminating complicated setup procedures and calibration runs, this system increases the practicality of measuring gene expression at a high temporal frequency.

Small open-deck roll-on/roll-off passenger ferries in Indonesia have a poor safety record. The Indonesian Government is interested in means by which the safety of these vessels can be improved, and this was the main catalyst for commencing research in this area. Any solution should be capable of being retrofitted to both existing vessels and new designs to improve their stability and, hence, their safety. The research therefore focused on the intact stability of the bare hulls, and with addition of side casings, for the vessels for which data was made available by the Indonesian Government. The research covered both quasi-static analysis, based on the objective of meeting the IMO intact stability criteria, and a dynamic approach using time-domain simulation in regular beam waves. A parametric study of the stability parameters of the twenty vessels demonstrated that, without the presence of side casings, the vessels had difficulties in complying with the IMO intact stability criteria. The problems were solved by introducing side casings (watertight spaces above the vehicle deck) either inboard of the vessel’s side-shell plating, or partially inboard and partially outboard of the side shell. The minimum extent (breadth) of side casings required was determined by iteration on each of the twenty vessels, incorporating variations in the height of the centre of gravity and loading conditions. The implementation of the minimum side casings showed that each vessel then met the IMO intact stability criteria. However, the assessment of the vessels’ dynamic stability characteristics using time-domain simulation provided inconsistent results for these vessels with side casings which met the IMO intact stability criteria. For some particular conditions, the existence and the different forms of side casings could decrease vessel survivability by increasing the roll motion amplitudes for both inside and outside casings and could lead the vessel to capsize. The results of the dynamic stability analysis also confirmed the vulnerability of small vessels with small stability parameters to large waves, and the different roll seakeeping behavior of the different vessel stability parameters.

Small open-deck roll-on/roll-off passenger ferries in Indonesia have a poor safety record. The Indonesian Government is interested in means by which the safety of these vessels can be improved, and this was the main catalyst for commencing research in this area. Any solution should be capable of being retrofitted to both existing vessels and new designs to improve their stability and, hence, their safety. The research therefore focused on the intact stability of the bare hulls, and with addition of side casings, for the vessels for which data was made available by the Indonesian Government. The research covered both quasi-static analysis, based on the objective of meeting the IMO intact stability criteria, and a dynamic approach using time-domain simulation in regular beam waves. A parametric study of the stability parameters of the twenty vessels demonstrated that, without the presence of side casings, the vessels had difficulties in complying with the IMO intact stability criteria. The problems were solved by introducing side casings (watertight spaces above the vehicle deck) either inboard of the vessel’s side-shell plating, or partially inboard and partially outboard of the side shell. The minimum extent (breadth) of side casings required was determined by iteration on each of the twenty vessels, incorporating variations in the height of the centre of gravity and loading conditions. The implementation of the minimum side casings showed that each vessel then met the IMO intact stability criteria. However, the assessment of the vessels’ dynamic stability characteristics using time-domain simulation provided inconsistent results for these vessels with side casings which met the IMO intact stability criteria. For some particular conditions, the existence and the different forms of side casings could decrease vessel survivability by increasing the roll motion amplitudes for both inside and outside casings and could lead the vessel to capsize. The results of the dynamic stability analysis also confirmed the vulnerability of small vessels with small stability parameters to large waves, and the different roll seakeeping behavior of the different vessel stability parameters.

Thesis (Ph.D.)--McMaster University, 2005. / Supervisor: W.-P. Huang Includes bibliographical references (leaves 124-136).