ASU Electronic Theses and Dissertations

Permanent Link Feedback

Contributor
Date Range
2010 2017

With the penetration of distributed renewable energy and the development of semiconductor technology, power electronic devices could be utilized to interface re- newable energy generation and the distribution power grid. However, when directly connected to the power grid, the semiconductors inside the power electronic devices could be vulnerable to the power system transient, especially to lightning strikes. The work of this research focuses on the insulation coordination of power elec- tronic devices connected directly to the power distribution system. The Solid State Transformer (SST) in Future Renewable Electric Energy Delivery and Management (FREEDM) system could be a good example for ...

Contributors
Rong, Xuening, Karady, George G, Heydt, Gerald T, et al.
Created Date
2017

Electric power system security assessment is one of the most important requirements for operational and resource planning of the bulk power system ensuring safe operation of the power system for all credible contingencies. This deterministic approach usually provides a conservative criterion and can result in expensive bulk system expansion plans or conservative operating limits. Furthermore, with increased penetration of converter-based renewable generation in the electric grid, the dynamics of the grid are changing. In addition, the variability and intermittency associated with the renewable energy sources introduce uncertainty in the electricity grid. Since security margins have direct economic impact on the ...

Contributors
Datta, Sohom, Vittal, Vijay, Undrill, John, et al.
Created Date
2017

Two major challenges in the transformer-less, single-phase PV string inverters are common mode leakage currents and double-line-frequency power decoupling. In the proposed doubly-grounded inverter topology with innovative active-power-decoupling approach, both of these issues are simultaneously addressed. The topology allows the PV negative terminal to be directly connected to the neutral, thereby eliminating the common-mode ground-currents. The decoupling capacitance requirement is minimized by a dynamically-variable dc-link with large voltage swing, allowing an all-film-capacitor implementation. Furthermore, the use of wide-bandgap devices enables the converter operation at higher switching frequency, resulting in smaller magnetic components. The operating principles, design and optimization, and control ...

Contributors
Xia, Yinglai, Ayyanar, Raja, Karady, George, et al.
Created Date
2017

With the increasing penetration of Photovoltaic inverters, there is a necessity for recent PV inverters to have smart grid support features for increased power system reliability and security. The grid support features include voltage support, active and reactive power control. These support features mean that inverters should have bidirectional power and communication capabilities. The inverter should be able to communicate with the grid utility and other inverter modules. This thesis studies the real time simulation of smart inverters using PLECS Real Time Box. The real time simulation is performed as a Controller Hardware in the Loop (CHIL) real time simulation. ...

Contributors
Thiagarajan, Ramanathan, Ayyanar, Raja, Lei, Qin, et al.
Created Date
2017

After a major disturbance, the power system response is highly dependent on protection schemes and system dynamics. Improving power systems situational awareness requires proper and simultaneous modeling of both protection schemes and dynamic characteristics in power systems analysis tools. Historical information and ex-post analysis of blackouts reaffirm the critical role of protective devices in cascading events, thereby confirming the necessity to represent protective functions in transient stability studies. This dissertation is aimed at studying the importance of representing protective relays in power system dynamic studies. Although modeling all of the protective relays within transient stability studies may result in a ...

Contributors
Hedman, Mojdeh Khorsand, Vittal, Vijay, Ayyanar, Raja, et al.
Created Date
2017

This thesis investigates different unidirectional topologies for the on-board charger in an electric vehicle and proposes soft-switching solutions in both the AC/DC and DC/DC stage of the converter with a power rating of 3.3 kW. With an overview on different charger topologies and their applicability with respect to the target specification a soft-switching technique to reduce the switching losses of a single phase boost-type PFC is proposed. This work is followed by a modification to the popular soft-switching topology, the dual active bridge (DAB) converter for application requiring unidirectional power flow. The topology named as the semi-dual active bridge (S-DAB) ...

Contributors
Kulasekaran, Siddharth, Ayyanar, Raja, Karady, George, et al.
Created Date
2017

Alternate sources of energy such as wind, solar photovoltaic and fuel cells are coupled to the power grid with the help of solid state converters. Continued deregulation of the power sector coupled with favorable government incentives has resulted in the rapid growth of renewable energy sources connected to the distribution system at a voltage level of 34.5kV or below. Of late, many utilities are also investing in these alternate sources of energy with the point of interconnection with the power grid being at the transmission level. These converter interfaced generation along with their associated control have the ability to provide ...

Contributors
Ramasubramanian, Deepak, Vittal, Vijay, Undrill, John, et al.
Created Date
2017

The power system is the largest man-made physical network in the world. Performing analysis of a large bulk system is computationally complex, especially when the study involves engineering, economic and environmental considerations. For instance, running a unit-commitment (UC) over a large system involves a huge number of constraints and integer variables. One way to reduce the computational expense is to perform the analysis on a small equivalent (reduced) model instead on the original (full) model. The research reported here focuses on improving the network reduction methods so that the calculated results obtained from the reduced model better approximate the performance ...

Contributors
Zhu, Yujia, Tylavsky, Daniel John, Vittal, Vijay, et al.
Created Date
2017

Presently, hard-switching buck/boost converters are dominantly used for automotive applications. Automotive applications have stringent system requirements for dc-dc converters, such as wide input voltage range and limited EMI noise emission. High switching frequency of the dc-dc converters is much desired in automotive applications for avoiding AM band interference and for compact size. However, hard switching buck converter is not suitable at high frequency operation because of its low efficiency. In addition, buck converter has high EMI noise due to its hard-switching. Therefore, soft-switching topologies are considered in this thesis work to improve the performance of the dc-dc converters. Many soft-switching ...

Contributors
Nan, Chenhao, Ayyanar, Raja, Bakkaloglu, Bertan, et al.
Created Date
2016

The past decades have seen a significant shift in the expectations and requirements re-lated to power system analysis tools. Investigations into major power grid disturbances have suggested the need for more comprehensive assessment methods. Accordingly, sig-nificant research in recent years has focused on the development of better power system models and efficient techniques for analyzing power system operability. The work done in this report focusses on two such topics 1. Analysis of load model parameter uncertainty and sensitivity based pa-rameter estimation for power system studies 2. A systematic approach to n-1-1 analysis for power system security as-sessment To assess the ...

Contributors
Mitra, Parag, Vittal, Vijay, Heydt, Gerald T, et al.
Created Date
2016

This collection includes most of the ASU Theses and Dissertations from 2011 to present. ASU Theses and Dissertations are available in downloadable PDF format; however, a small percentage of items are under embargo. Information about the dissertations/theses includes degree information, committee members, an abstract, supporting data or media.

In addition to the electronic theses found in the ASU Digital Repository, ASU Theses and Dissertations can be found in the ASU Library Catalog.

Dissertations and Theses granted by Arizona State University are archived and made available through a joint effort of the ASU Graduate College and the ASU Libraries.

For more information or questions about this collection contact or visit the Digital Repository ETD Library Guide or contact the ASU Graduate College at gradformat@asu.edu.