Browsing by Author "dos Santos, Euzeli Cipriano"

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    Applying Different Wide-Area Response-Based Controls to Different Contingencies in Power Systems
    (2019-08) Iranmanesh, Shahrzad; Steven, Rovnyak; King, Brian; dos Santos, Euzeli Cipriano
    The electrical disturbances in the power system have threatened the stability of the system. In the first step, it is necessary to detect these electrical disturbances or events. In the next step, a proper control should apply to the system to decrease the consequences of the disturbances. One-shot control is one of the effective methods for stabilizing the events. In this method, a proper amount of loads are increased or decreased to the electrical system. Determining the amounts of loads, and the location for shedding is crucial. Moreover, some control combinations are more effective for some events and less effective for some others. Therefore, this project is completed in two different sections. First, finding the effective control combinations, second, finding an algorithm for applying different control combinations to different contingencies in real-time. To find effective control combinations, sensitivity analysis is employed to locate the most effective loads in the system. Then to find the control combination commands, gradient descent, and PSO algorithm are used in this project. In the next step, a pattern recognition method is used to apply the appropriate control combination for every event. The decision tree is selected as the pattern recognition method. The three most effective control combinations found by sensitivity analysis and the PSO method are used in the remainder of this study. A decision tree is trained for each of the three control combinations, and their outputs are combined into an algorithm for selecting the best control in real-time. Finally, the algorithm is evaluated using a test set of contingencies. The final results reveal a 30\% improvement in comparison to the previous studies.
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    Power electronics solutions for uninterrupted power supply and grid-tie inverters
    (2014-11-21) Nezamuddin, Omar N.; dos Santos, Euzeli Cipriano; Rizkalla, Maher E.; Rovnyak, Steven
    This thesis proposes two new topologies for Uninterrupted Power Supply (UPS), and a grid-tie microinverter. The first topic will discuss an on-line transformerless UPS system based on the integrated power electronics converters that is able to control the input power factor, charge the battery, and guarantee backup operation of the system. The main advantages of the proposed UPS are active power factor correction (PFC) without the need of a complex control scheme, and integrated functions of the battery charger circuit and PFC with only three power switches. Operation modes of the system and the PWM strategy is presented in detail. The second topic discussed is of a proposed circuitry for a single-phase back-to-back converter for UPS applications. The main advantages of this topology is higher number of levels at the rectifier side, less number of power switches, and no need for a boost inductor at the input side of the converter. The last topic discussed is of a proposed patent pending microinverter. This topic was a project funded by the National Science Foundation, and its aim was to help commercialize the research. This project proposes a solution for a solar inverter called Delta Microinverter that allows easier and faster installation as well as power conversion with higher efficiency. Delta Microinverters innovation is found in its patent-pending shape and in its patent-pending circuitry, i.e., electronics mounted inside of the Delta Microinverter. The Delta Microinverters shape has a housing configured for rapid mounting using a single fastener and its power electronics configuration offers an optimized relationship between the number of levels and number of power switches.