Indiana University-Purdue University Indianapolis (IUPUI) / This study contributes to a better understanding of ignition by hot combustion gases which finds application in internal combustion chambers with pre-chamber ignition as well as in wave rotor engine applications. The experimental apparatus consists of two combustion chambers: a pre chamber that generates the transient hot jet of gas and a main chamber which contains the main fuel air blend under study. Variables considered are three fuel mixtures (Hydrogen, Methane, 50\% Hydrogen-Methane), initial pressure in the pre-chamber ranging from 1 to 2 atm, equivalence ratio of the fuel air mixture in the main combustion chamber ranging from 0.4 to 1.5, and initial temperature of the main combustion chamber mixture ranging from 297 K to 500 K. Experimental data makes use of 4 pressure sensors with a recorded sampling rate up to 300 kHz, as well as high speed Schlieren imaging with a recorded frame rate up to 20,833 frame per seconds. Results shows an overall increase in ignition delay with increasing equivalence ratio. High temperature of the main chamber blend was found not to affect hot jet ignition delay considerably. Physical mixing effects, and density of the main chamber mixture have a greater effect on hot jet ignition delay.

Medium-voltage (MV) motor drives have found widespread applications in various heavy industries, such as in the oil and gas sectors, production plants, and process industries. Conventional cascaded H-bridge (CHB) multilevel inverters dominate the medium-voltage industrial drives domain due to their modularity, scalability, and reliability. The most prevalent CHB topology in the drive industry is based on the diodes-front-end (DFE) rectifier, which greatly limits the industrial application of the conventional CHB drives where the ability of handling regeneration is required. The main objective of this thesis is to develop a low-cost, high performance, reliable regenerative CHB drive. The thesis is concentrating on reducing the grid-tied filter size, shrinking the DC-link capacitors, improving the system’s performance and reliability through advanced control techniques. First, to reduce the number of passive filter components, a new sideband harmonic active filtering strategy based on the carrier-shifting method is proposed for regenerative CHB drives. This proposed approach extends the carrier shifted PWM method for regenerative CHB drives to further reduce the required passive filter size significantly and thus improves the overall size, cost, and efficiency while complying with IEEE Std 519-2014 grid standard. Second, a novel voltage ripple controller is proposed to reduce the dc-link capacitance in the three-phase regenerative CHB drive without adding extra measurements. Third, to achieve a faster dynamic response and the multi-objective performance during the control of CHB drives, a novel high-performance predictive control with long prediction horizons is proposed to improve the control performance of the CHB multilevel inverters. The formulation of the proposed high-performance finite control set model predictive control (FCS-MPC) is explained in detail and analyzed to reduce the real-time computation burden. Last, when a fault is detected in the regenerative CHB drive system, the reliability and fault-tolerant ability are considered as the main issues. To improve the drive system reliability, a non-symmetrical selective harmonic elimination (SHE) formulation is proposed to extend the output voltage range with a good harmonic profile under post-fault conditions. Experimental validation of the proposed algorithms is presented for the operation of a scaled-down seven-level regenerative CHB drive system. These proposed techniques make the regenerative CHB drive a promising solution for future medium-voltage regenerative drive applications in terms of cost, performance, and reliability. / Thesis / Doctor of Philosophy (PhD)

Tidigare forskning tyder på att risken för agentkostnader är höga inom ömsesidiga bolag, i och med den unika ägarstrukturen som separerar ägandet och kontroll. Detta belyser vikten av ett fungerande kontrollsystem, samtidigt är controllern starkt kopplad till övervakning och granskning utav verksamheter. Däremot beskrivs controllern som diffus och svårdefinierad, varpå det är svårt att uttala sig om dennes relation till agentkostnader. Således undersöker denna studie hur en controller kan konkretiseras och om det finns en roll som minskar agentkostnader inom ett ömsesidigt bolag samt hur den i så fall gör detta. Vilket motiverar en teoretisk referensram innehållandes agentteori och tidigare forskning gällande controllern. Undersökningen baseras på en kvalitativ ansats med en fallstudiedesign. Varpå resultatet tyder på att konkretisering utav en controller inte är möjlig utefter distinkta kategorier, utan är mer riktig då dess roll inte definieras utefter skarpa kategorier utan kan infinnas på en skala. Dessutom innehar controllerrollen som minskar agentkostnader i ett ömsesidigt bolag egenskaper som återfinns inom rollen affärspartner. Detta gör hen genom att lägga mindre tid på rutinmässiga arbetsuppgifter och mer fokus på strategiska ställningstaganden utefter kundernas, det vill säga ägarnas, intressen. Något som minskar risken för agentkostnader.

In this study, two new Multi-Objective Optimization (MOO) techniques are developed. The two new techniques, the Objective-Based Gradient Algorithm (OBGA) and the Principal Component Grid Algorithm (PCGA), were developed with the goals of improving the accuracy and efficiency of the Pareto domain approximation relative to current MOO techniques. Both methods were compared to current MOO techniques using several test problems. It was found that both the OBGA and PCGA systematically produced a more accurate Pareto domain than current MOO techniques used for comparison, for all problems studied. The OBGA requires less computation time than the current MOO methods for relatively simple problems whereas for more complex objective functions, the computation time was larger. On the other hand, the efficiency of the PCGA was higher than the current MOO techniques for all problems tested. The new techniques were also applied to complex chemical engineering problems. The OBGA was applied to an industrial reactor producing ethylene oxide from ethylene. The optimization varied four of the reactor input parameters, and the selectivity, productivity and a safety factor related to the presence of oxygen in the reactor were maximized. From the optimization results, recommendations were made based on the ideal reactor operating conditions, and the control of key reactor parameters. The PCGA was applied to a PI controller model to develop new tuning methods based on the Pareto domain. The developed controller tuning methods were compared to several previously developed controller correlations. It was found that all previously developed controller correlations showed equal or worse performance than that based on the Pareto domain. The tuning methods were applied to a fourth order process and a process with a disturbance, and demonstrated excellent performance.

Under the initiative of Department of Transportation (DOT) a safety-critical, dual redundant, open source traffic signal control application is currently being developed. The system named SCOPE, for Signal Control Program Environment, currently implements standard 8-phase NEMA logic and the National Cooperative Highway Research Program 3-66 preemption logic. SCOPE is designed to be part of the Advanced Traffic Controller (ATC), making use of API standard 2.06b to integrate with the hardware. Safety-critical status is achieved through redundancy of application logic that constantly compares expected signal phase information. From baseline requirements, engineers independently program application code, one using Ada95 and the other using C++. The Traffic EXperimental Analytical Simulation Model, a microscopic single-intersection vehicular simulation, was used for initial validation and testing of the functionality of the system. The second demonstration of the SCOPE, used actuated detector data collected from a recording of a live intersection. Actuator calls were placed on SCOPE at the same times the vehicles triggered the detectors in the video (assuming the vehicles were not in-queue). Using SCOPE the real-world traffic was not only right-of-way safely yielded, but the traffic flow state time average time in-queue reduced. The final phase of testing will occur when the DOT performs Formal Qualification Testing, which is scheduled for 2013. Upon validation and subsequent release to the open source community SCOPE will provide users the ability to replace the proprietary application software residing in ATC cabinets. Transparency will be provided into another aspect of the traffic control signal thus taking the initiative of ATC one step further.

Traditional call button networks that control elevator systems utilize a wired connection for communication. The communication cables are run through the elevator shaft from one call button to another and finally to the controller on the roof. Installing this wired link is highly time consuming. In this thesis, we propose the design for a wireless call button network. Two important features of this wireless network design are low cost and low power consumption. Controller Area Network (CAN) is a widely used protocol for wired networks and has been proposed for use in next generation elevator control systems. A modified CAN for wireless (MCANW) protocol has been developed for the wireless call button network. The wireless link will be implemented via the use of data radios. A modified form of traditional Binary Phase Shift Keying (BPSK) modulation scheme for the radios is proposed. The proposed modulation scheme, like differential BPSK, can be detected non-coherently but it offers better performance than differential BPSK. Its implementation includes an innovative tracking algorithm to maintain synchronization at the receiver. / Master of Science

This thesis details a higher-fidelity, scalable simulation tool and model for message response time and bus utilization rate analysis for the Controller Area Network (CAN) protocol stack. This tool achieves higher fidelity than existing commercial and academic simulation tools by including details of the stack implementation that are often neglected, such as receive and transmit hardware buffer availability and usage policy (i.e., which messages are able to be copied to which buffer resources), and the buffer polling or queueing policies. Key details of these features have been identified by a thorough examination of CAN stack behaviour, taking into account the physical considerations of commercial CAN implementations. Inclusion of these details in the simulation can produce better accuracy by exposing certain priority inversion scenarios. Scalability is achieved by using a transaction-based modelling approach and modelling transmissions at the protocol level rather than the physical/bit level. The tool requires minimal user interaction, and system level model generation is automated using an AUTOSAR XML system description file (ARXML format) to specify network topology and message information (transmitter, receiver(s), period, length, etc.), and an Excel spreadsheet file (XLS or XLSX format) to specify node hardware/software implementation details (buffer resource details, polling loop rates, main control loop rates, etc.) as inputs. / Thesis / Master of Applied Science (MASc)

<p> The Serial Output Controller is one of the component boards of a Marine Navigation System. Litton Systems (Canada) Limited required the development of a test package for this board to be implemented on the DIGIPACT test station. This report introduc.es the subject of electronic component board testing with an overview of the test equipment and underlying philosophies used by Litton Systems for fault detection and fault diagnosis. The four stages of the test package development process, test plan definition, programming, validation and evaluation are described. The architecture of the DIGIPACT test system is presented as background information. </p> / Thesis / Master of Engineering (MEngr)

<p> The topic of study within includes the development and application of nonlinear control technologies on sampled systems. Discrete control structures are introduced that expand on existing differential geometric and predictive control methods. The differential geometric techniques are described from the error trajectory context, which are typically only derived for continuous application. The discrete error trajectory controllers introduced have one of two configurations. The first configuration requires satisfaction of the error trajectory objective at the next sampling interval through prediction of system behaviour over the controller sampling interval. This objective found limited success and it is observed that satisfaction of the error trajectory objective at discrete intervals does not generally result in the intended response. The second configuration minimizes the integrated distance from the error manifold defined by the error trajectory objective over the entire controller sampling interval. It is observed that this integrated error trajectory controller best emulates the intent of the continuous controller in the discrete domain. Techniques borrowed from predictive control are incorporated into the integrated error trajectory controller such as input move suppression and constraints to produce an optimal error trajectory controller, further improving performance.</p> <p> The predictive control method introduced utilizes a transformation of the input space. The differentiating property of input transformation predictive control (ITPC) from other methods is the prediction technique that is capable of estimating the future behaviour of nonlinear systems through elementary matrix operations similar to the dynamic matrix control (DMC) prediction technique. This is achieved by separation of the steady state and dynamic system properties and the introduction of an intermediate state prediction layer. This allows for the nonlinear prediction of system behaviour without the need to numerically integrate the system model.</p> <p> Two example systems are used to demonstrate application of the discrete error trajectory and ITPC on nonlinear controllers. Performance for these control structures is compared to technologies accepted within the control community for a broad range for characteristics including, computation efficiency, design effort and other nonlinear performance criteria, with favourable results.</p> / Thesis / Master of Engineering (MEngr)

<p> The transmit-power control (TPC) problem is a fundamental problem in cognitive radio design, which aims at determining transmit-power levels for secondary users across available subcarriers. This thesis studies both the theory and the algorithms for the TPC problem for cognitive radio networks, and specifically examines the problem under two different limitations: an interference-power limitation and a low-power limitation. First, the TPC problems are cast into game-theoretic models and the sufficient and necessary optimality conditions ·for solutions are derived. Sufficient conditions for the existence, uniqueness and stability of a solution are presented as well. Second, the fast iterative water-filling controller (FIWFC) for the TPC problem is developed, which is linearly convergent under certain conditions. The computational complexity is lower than for the iterative water-filling controller (IWFC) for digital subscriber lines. In order to evaluate the FIWFC, simulations are carried out for both stationary and nonstationary radio environments. In addition, the performance of the FIWFC is evaluated, given the presence of measurement errors. The results of these various simulations show that the FIWFC outperforms IWFC in terms of convergence speed in all cases. </p> / Thesis / Doctor of Philosophy (PhD)