Thesis (Ph.D.)--University of Nebraska-Lincoln, 2009. / Title from title screen (site viewed July 8, 2010). PDF text: ix, 195 p. : ill. (chiefly col.) ; 4 Mb. UMI publication number: AAT 3366273. Includes bibliographical references. Also available in microfilm and microfiche formats.

In order to achieve the ambitious decarbonisation targets of the UK government, up to 30GW of wind generation could be connected to the GB transmission system by 2020. The challenges imposed when incorporating this volume of renewable energy are significant, introducing new technical challenges for National Grid as the system operator for the Great Britain transmission system. The majority of this new renewable generation will be connecting in Scotland and offshore in the UK as a whole. This results in greater uncertainty in the system from significant changes to the direction and volume of power flows across the network. In addition this implies a higher power transfer capacity requirement on the AC transmission lines, which are currently stability-limited, connecting SPT (Scottish Power Transmission) and National Grid networks. The required power transfer capability increases every year because of the large-scale increase in wind generation. Therefore, there is insufficient transmission capacity in the existing network to accommodate the increasing power transfer without constraining output of some generation plants. A range of new state of art technologies such as embedded HVDC link and Thyristor Controlled Series Compensation (TCSC) are planned to be added to the GB system in order to provide additional capacity and consequently facilitate the integration of large-scale renewable generation. It is, therefore essential that National Grid explores new ways of operating the transmission network and new devices to gain additional benefit from the HVDC link and the TCSC capabilities with regard to the system stability enhancement. This thesis investigates the effectiveness of the HVDC link and the TCSC with a view to system stability enhancement. A hierarchical stability control system to enhance the stability limit and achieve the best transient and dynamic performance using the HVDC link and the TCSCs as actuators in the feedback control system is proposed. In addition, a stability control system, using a robust and stabilising Sample Regulator multivariable control design method , to guarantee the system robustness and stability is proposed and designed. The performance and capability of the designed controller in co-ordinated control of the forthcoming power flow control devices are demonstrated on benchmark networks as well as full dynamic models of the GB transmission system using various study cases. Finally, the effectiveness of the West Coast HVDC link in improving the inter-area oscillation damping is presented using the developed model of the future GB transmission system.

This project was the first step in developing a control system for the open slag bath furnace at Highveld Steel, in order to maximize production levels and product quality. In this dissertation, available knowledge from literature and practical experience is included. This is then processed to propose a realistic control system with the current resources available at Highveld Steel. Through research and practical experience it is shown that these furnaces are extremely sensitive to raw material quality and consistency of decision making. This is a result of the open bath configuration that necessitates the careful control of the excess energy, and the raw material composition supplied to the furnace. Through this project it was shown that both the productivity and the product quality (vanadium recovery) can be increased by simply controlling the feed-topower ratio and correct use of correction material. This has the effect of stabilizing the process energy balance which results in smaller slag temperature variations and therefore also less product quality variability. Through controlling the feed-power-ratio, energy consumption was also shown to be reduced, since excess power is minimized without negatively impacting on productivity. In this project a proposal is made to control the flow of material between the two stages in the process, which is based on either being kiln or furnace constrained. A better tapping scheduling is also proposed, based on both material accumulations inside the furnace and the charging condition of the furnace. This results in having sufficient pressure to tap iron and slag at good rates and should also yield consistent tapping weights and add to general process stability. However, engineering availability strongly impacts on both process control and furnace productivity. Consistent availability of the furnace and its supporting systems is hence essential for optimal operation. / Dissertation (MEng)--University of Pretoria, 2009. / Materials Science and Metallurgical Engineering / unrestricted

Rising demand for high productivity of machine tools leads to increase of the dynamics of the machine tool. With higher dynamics of the components is produced a free tool vibr ation that can affect the path accuracy of the feed axis and of the tool. In this thesis are examined various parameters of the feed axis, so that the influence of each parameter could be determined. To determine these factors is in this thesis created a structuralmechanical model of the feed axis by means of the finite element method and this thesis presents a connection of the FE model with a control loop of an axis that allows the theoretical study of the influences on the accuracy of the feed axis. The results show succes sful coupling of the FE model with the control loop. Selected parameters are analyzed in this paper.

This report describes the design and operation of an Automated Storage and Retrieval System (AS/RS) to serve the Flexible Manufacturing and Assembly System (FMAS) in the Manufacturing Systems Laboratory at Virginia Tech. The system requirements of the AS/RS, justification of design choices, and the proposed modes of operating the system are described. The AS/RS was designed to automatically move material on pallets between the storage racks in the laboratory to the FMAS conveyor interface. The system was designed and built, and has been tested to perform the desired operating functions. The scope of this project was limited to designing and installing the hardware component of the AS/RS, and testing it to ensure that it will satisfy the system requirements of the FMAS. The educational objective of the project is to enable fully automated control of all cell activities via the FMAS Computer Network. / Master of Science

Indiana University-Purdue University Indianapolis (IUPUI) / With the development of the electric mower, an electrical control system is necessary to drive the blades and the traction wheel. This thesis introduces an electrical deck control system. The system includes a high-powered deck controller and a permanent magnet synchronous motor (PMSM). A PMSM control model has been built in MATLAB/Simulink to verify and support the physical design. Three different PWM modulation methods have also been implemented and compared in MATLAB/Simulink. Furthermore, a model for the distribution and features of grass was built based on sampling of Google Street View images. A six-step pulse width modulation (PWM) control strategy was realized using a PIC33 embedded microprocessor. An enhanced closed-loop control system design was implemented to keep a constant blade speed in order to cut grass efficiently.

ICS security has been a topic of scrutiny and research for several years, and many security issues are well known. However, research efforts are impeded by a lack of an open virtual industrial control system testbed for security research. This thesis describes a virtual testbed framework using Python to create discrete testbed components (including virtual devices and process simulators). This testbed is designed such that the testbeds are interoperable with real ICS devices and that the virtual testbeds can provide comparable ICS network behavior to a laboratory testbed. Two testbeds based on laboratory testbeds have been developed and have been shown to be interoperable with real industrial control systemequipment and vulnerable to attacks in the samemanner as a real system. Additionally, these testbeds have been quantitatively shown to produce traffic close to laboratory systems (within 90% similarity on most metrics).

Predicting the performance of wind turbines is a key part of the turbine design process and operation, as predictive models play a large role in determining potential power output and efficiency at different operating conditions to help maximize production. On small-scale wind turbines performance models become more complex, as the rotor aerodynamic performance depends not only on the tip speed ratio, but also on the flow Reynolds number. An accurate predictive model that includes this behavior on small-scale wind turbines can be used to find the optimal operating conditions for power output, and is also a critical component of the design of a control system. This project aims to develop such a model for the small-scale wind turbine operated by the Cal Poly Wind Power Research Center, and to use the developed model to redesign the current control system. The full turbine system model developed in this project for the Cal Poly Wind Turbine includes detailed models of the aerodynamic, mechanical, and electrical subsystems on the turbine based on first- principles physics. Model parameters were determined through a combination of experimental testing and theoretical analysis. The full turbine model was compared against experimental data, showing that estimations from the predictive model matched closely with the true performance of the turbine. Through the model, the turbine was estimated to have a maximum efficiency of 83.63% and to produce a maximum total ���� of 35.93% at a tip speed ratio around 5. Using the performance information from the model, a new non-linear controller was designed for constant speed, constant tip speed ratio, and maximum power output. The new maximum power controller is predicted to increase the overall power production of the turbine by 17.1% over the course of a year.

The increasing demand for sustainable transportation solutions has led to the rapid evolution of hybrid and electric vehicles. This thesis, undertaken as part of the EcoCAR Mobility Challenge, presents the development and implementation of a control system for a P4 parallel through-the-road hybrid electric vehicle. A comprehensive vehicle model was developed using MATLAB Simulink. This model was used to model overall vehicle performance and component-specific performance throughout the EcoCAR Mobility Challenge and served as the foundation for the subsequent stages of control system development. Extensive component and vehicle testing formed the crux of this thesis. These bench tests provide invaluable data that aided in the implementation of the component control loops into the MAC Team vehicle. On-road vehicle testing further refined the energy management strategy, drivability, and charge sustaining of the high voltage battery. The vehicle control system has 10 control modules that successfully operated the MAC Team vehicle for over 1500km on public roads. The methodologies and findings can guide future projects aiming to optimize hybrid vehicle performance. / Thesis / Master of Applied Science (MASc) / With hybrid electric vehicles and electric vehicles rising in popularity, the EcoCAR Mobility Challenge and its sponsors created an opportunity for McMaster University and 10 other universities across North America to modify a 2019 Chevrolet Blazer into a hybrid electric vehicle. This thesis focuses on the development of the control strategy for the McMaster University vehicle. A mathematical vehicle model was developed to run vehicle simulations in order to evaluate vehicle performance and the performance of individual components. Individual components were tested in order to develop control loops for these components. These control loops and other control modules were used during vehicle testing. On-road vehicle testing refined the vehicle control strategy evidenced by the over 1500km driven on public roads.

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