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- Genre: Doctoral Dissertation
- Creators: Ayyanar, Raja
Description
Traditional approaches to modeling microgrids include the behavior of each inverter operating in a particular network configuration and at a particular operating point. Such models quickly become computationally intensive for large systems. Similarly, traditional approaches to control do not use advanced methodologies and suffer from poor performance and limited operating range. In this document a linear model is derived for an inverter connected to the Thevenin equivalent of a microgrid. This model is then compared to a nonlinear simulation model and analyzed using the open and closed loop systems in both the time and frequency domains. The modeling error is quantified with emphasis on its use for controller design purposes. Control design examples are given using a Glover McFarlane controller, gain sched- uled Glover McFarlane controller, and bumpless transfer controller which are compared to the standard droop control approach. These examples serve as a guide to illustrate the use of multi-variable modeling techniques in the context of robust controller design and show that gain scheduled MIMO control techniques can extend the operating range of a microgrid. A hardware implementation is used to compare constant gain droop controllers with Glover McFarlane controllers and shows a clear advantage of the Glover McFarlane approach.
ContributorsSteenis, Joel (Author) / Ayyanar, Raja (Thesis advisor) / Mittelmann, Hans (Committee member) / Tsakalis, Konstantinos (Committee member) / Tylavsky, Daniel (Committee member) / Arizona State University (Publisher)
Created2013
Description
Libby Larsen is one of the most performed and acclaimed composers today. She is a spirited, compelling, and sensitive composer whose music enhances the poetry of America's most prominent authors. Notable among her works are song cycles for soprano based on the poetry of female writers, among them novelist and poet Willa Cather (1873-1947). Larsen has produced two song cycles on works from Cather's substantial output of fiction: one based on Cather's short story, "Eric Hermannson's Soul," titled Margaret Songs: Three Songs from Willa Cather (1996); and later, My Antonia (2000), based on Cather's novel of the same title. In Margaret Songs, Cather's poetry and short stories--specifically the character of Margaret Elliot--combine with Larsen's unique compositional style to create a surprising collaboration. This study explores how Larsen in these songs delves into the emotional and psychological depths of Margaret's character, not fully formed by Cather. It is only through Larsen's music and Cather's poetry that Margaret's journey through self-discovery and love become fully realized. This song cycle is a glimpse through the eyes of two prominent female artists on the societal pressures placed upon Margaret's character, many of which still resonate with women in today's culture. This study examines the work Margaret Songs by discussing Willa Cather, her musical influences, and the conditions surrounding the writing of "Eric Hermannson's Soul." It looks also into Cather's influence on Libby Larsen and the commission leading to Margaret Songs. Finally, a description of the musical, dramatic, and textual content of the songs completes this interpretation of the interactions of Willa Cather, Libby Larsen, and the character of Margaret Elliot.
ContributorsMcLain, Christi Marie (Author) / FitzPatrick, Carole (Thesis advisor) / Dreyfoos, Dale (Committee member) / Holbrook, Amy (Committee member) / Ryan, Russell (Committee member) / Arizona State University (Publisher)
Created2013
Description
Arnold Schoenberg's 1908-09 song cycle, Das Buch der hängenden Gärten [The Book of the Hanging Gardens], opus 15, represents one of his most decisive early steps into the realm of musical modernism. In the midst of personal and artistic crises, Schoenberg set texts by Stefan George in a style he called "pantonality," and described his composition as radically new. Though stylistically progressive, however, Schoenberg's musical achievement had certain ideologically conservative roots: the composer numbered among turn-of-the-century Viennese artists and thinkers whose opposition to the conventional and the popular--in favor of artistic autonomy and creativity--concealed a reactionary misogyny. A critical reading of Hanging Gardens through the lens of gender reveals that Schoenberg, like many of his contemporaries, incorporated strong frauenfeindlich [anti-women] elements into his work, through his modernist account of artistic creativity, his choice of texts, and his musical settings. Although elements of Hanging Gardens' atonal music suggest that Schoenberg valued gendered-feminine principles in his compositional style, a closer analysis of the work's musical language shows an intact masculinist hegemony. Through his deployment of uncanny tonal reminiscences, underlying tonal gestures, and closed forms in Hanging Gardens, Schoenberg ensures that the feminine-associated "excesses" of atonality remain under masculine control. This study draws upon the critical musicology of Susan McClary while arguing that Schoenberg's music is socially contingent, affected by the gender biases of his social and literary milieux. It addresses likely influences on Schoenberg's worldview including the philosophy of Otto Weininger, Freudian psychoanalysis, and a complex web of personal relationships. Finally, this analysis highlights the relevance of Schoenberg's world and its constructions of gender to modern performance practice, and argues that performers must consider interrelated historical, textual, and musical factors when interpreting Hanging Gardens in new contexts.
ContributorsGinger, Kerry Anne (Author) / FitzPatrick, Carole (Thesis advisor) / Dreyfoos, Dale (Committee member) / Mook, Richard (Committee member) / Norton, Kay (Committee member) / Ryan, Russell (Committee member) / Arizona State University (Publisher)
Created2012
Description
ABSTRACT This document introduces singers and voice teachers to Dr. Alfred A. Tomatis's listening training method with a particular emphasis on its relevance to singers. After presenting an overview of Tomatis's work in the field of audio-psycho-phonology (circa 1947 through the 1990s) and specific ways that aspects of his theory are relevant to singers' performance skills, this project investigates the impact of listening training on singers by examining published research. The studies described in this document have investigated the impact of listening training on elements of the singer's skill set, including but not limited to measures of vocal quality such as intonation, vocal control, intensity, and sonority, as well as language pronunciation and general musicianship. Anecdotal evidence, presented by performers and their observers, is also considered. The evidence generated by research studies and anecdotal reports strongly favors Tomatis-based listening training as a valid way to improve singers' performance abilities.
ContributorsHurley, Susan Lynn (Author) / Doan, Jerry (Thesis advisor) / Dreyfoos, Dale (Committee member) / Kopta, Anne (Committee member) / Norton, Kay (Committee member) / Thompson, Billie M (Committee member) / Arizona State University (Publisher)
Created2012
Description
This dissertation presents a new hybrid fault current limiter (FCL) topology that is primarily intended to protect single-phase power equipment. It can however be extended to protect three phase systems but would need three devices to protect each individual phase. In comparison against the existing fault current limiter technology, the salient fea-tures of the proposed topology are: a) provides variable impedance that provides a 50% reduction in prospective fault current; b) near instantaneous response time which is with-in the first half cycle (1-4 ms); c) the use of semiconductor switches as the commutating switch which produces reduced leakage current, reduced losses, improved reliability, and a faster switch time (ns-µs); d) zero losses in steady-state operation; e) use of a Neodym-ium (NdFeB) permanent magnet as the limiting impedance which reduces size, cost, weight, eliminates DC biasing and cooling costs; f) use of Pulse Width Modulation (PWM) to control the magnitude of the fault current to a user's desired level. g) experi-mental test system is developed and tested to prove the concepts of the proposed FCL. This dissertation presents the proposed topology and its working principle backed up with numerical verifications, simulation results, and hardware implementation results. Conclu-sions and future work are also presented.
ContributorsPrigmore, Jay (Author) / Karady, George G. (Thesis advisor) / Ayyanar, Raja (Committee member) / Holbert, Keith E. (Committee member) / Hedman, Kory (Committee member) / Arizona State University (Publisher)
Created2013
Description
The trained singer utilizes an awareness of her body as an instrument. When she becomes pregnant, her body changes in numerous ways to support the pregnancy. Many of these changes have great impact on her ability to sing during the pregnancy and postpartum periods. The voice may be altered positively or negatively by the release of hormones. The body undergoes many changes that affect the posture and breathing required for singing. Most notably, the abdominal muscles are greatly impacted by the pregnancy. They are stretched by the growing uterus, and this affects their function. In addition, the linea alba (the connective tissue between the halves of the rectus abdominis) is softened by hormonal increases and subject to stretching as the uterus grows, predisposing it to weakness. Since the other abdominal muscles attach to the linea alba via connective tissue, maintaining the integrity of the linea alba during pregnancy and postpartum is vital to the operational function of the abdominal muscles. Protecting the vulnerable linea alba must be deliberately undertaken in two parts. First, conscious exercise is needed to preserve the linea alba during pregnancy and to rehabilitate it after pregnancy. Targeted exercises strengthen the transverse abdominis and shorten and approximate the two halves of the rectus abdominis. Second, modifications in daily movement are necessary to protect the linea alba while performing routine activities. Cesarean sections present additional surgical concerns for singers, including abdominal incisions, use of medication, and the rare need for general anesthesia via intubation. Recovery from a cesarean can be difficult due to abdominal pain, yet steps may be taken to speed healing at the hospital and at home. This paper provides an overview of how pregnancy affects the singer, discusses the effects of pregnancy and cesarean section, and provides a plan to protect the abdominal muscles during pregnancy and rehabilitate them in the postpartum period. It combines information from the fields of physical therapy, medicine, and surgery into a guide for the singer and voice teacher.
ContributorsWill, Andrea Pitman (Author) / Doan, Jerry (Thesis advisor) / Elgar Kopta, Anne (Thesis advisor) / Dreyfoos, Dale (Committee member) / Mills, Robert (Committee member) / Oldani, Robert W (Committee member) / Arizona State University (Publisher)
Created2013
Description
This paper and its accompanying recital examine three solo vocal works by Italian composer Alfredo Casella (1883-1947): "Larmes" from Cinq Mélodies (Op. 2); "Mort, ta servante est à ma porte" from L'adieu à la vie: Quatre lyriques funèbres extraites du "Gitanjali" de Rabindranath Tagore (Op. 26); and "Amante sono, vaghiccia, di voi" from Tre canzoni trecentesche (Op. 36). Each of these songs is discussed as representative of Casella's three compositional periods. A fourth song, "Ecce odor filii mei" from Tre canti sacri per baritono et organo (Op. 66), is also examined, as an end-of-life composition. Some of the more important solo vocal works composed in each period are mentioned to show where the four selected songs fit into Casella's compositional output and to suggest music for further study or repertoire.
ContributorsGordon, Stefan (Author) / Mills, Robert (Thesis advisor) / Holbrook, Amy (Committee member) / FitzPatrick, Carole (Committee member) / Dreyfoos, Dale (Committee member) / Arizona State University (Publisher)
Created2014
Description
The purpose of this study is to examine and explore Hatha Yoga and how it relates to a practice consisting of singer-friendly yoga postures, how these postures may benefit the singer's mental and physical health, and how these techniques relate to designated research. The study also investigates yogic breathing techniques and how these exercises relate to selected research. Lastly, the paper examines how the voice student and professional singer may alleviate anxiety by introducing a practice of daily yogic mediation of mudra and mantra techniques, and how voice teachers may better understand and assist their students with stage performance anxiety.
ContributorsHutton, Christopher (Singer) (Author) / Rogers, Rodney (Thesis advisor) / Doan, Jerry (Committee member) / Dreyfoos, Dale (Committee member) / Kopta, Anne (Committee member) / May, Judy (Committee member) / Arizona State University (Publisher)
Created2014
Description
From the time it was written, the aria "Largo al factotum" from Rossini's Il barbiere di Siviglia has been performed and ornamented in many different ways. The present study is an inventory and analysis of ornaments sung in 33 recordings from 1900 to 2011 and the major differences that they exhibit one from another. The singers in this study are baritones with international careers, who have performed the role of Figaro either at the Metropolitan Opera (New York) or at La Scala (Milan). The study identifies and tracks some of the changes in the ornamentation of the aria by noting common traits and new approaches across the one hundred eleven years of practice illustrated by the recordings.
ContributorsBriggs, Andrew Nathan (Author) / Mills, Robert (Committee member) / Oldani, Robert (Committee member) / Dreyfoos, Dale (Committee member) / FitzPatrick, Carole (Committee member) / Ryan, Russell (Committee member) / Arizona State University (Publisher)
Created2014
Description
A new photovoltaic (PV) array power converter circuit is presented. The salient features of this inverter are: transformerless topology, grounded PV array, and only film capacitors. The motivations are to reduce cost, eliminate leakage ground currents, and improve reliability. The use of Silicon Carbide (SiC) transistors is the key enabling technology for this particular circuit to attain good efficiency.
Traditionally, grid connected PV inverters required a transformer for isolation and safety. The disadvantage of high frequency transformer based inverters is complexity and cost. Transformerless inverters have become more popular recently, although they can be challenging to implement because of possible high frequency currents through the PV array's stay capacitance to earth ground. Conventional PV inverters also typically utilize electrolytic capacitors for bulk power buffering. However such capacitors can be prone to decreased reliability.
The solution proposed here to solve these problems is a bi directional buck boost converter combined with half bridge inverters. This configuration enables grounding of the array's negative terminal and passive power decoupling with only film capacitors.
Several aspects of the proposed converter are discussed. First a literature review is presented on the issues to be addressed. The proposed circuit is then presented and examined in detail. This includes theory of operation, component selection, and control systems. An efficiency analysis is also conducted. Simulation results are then presented that show correct functionality. A hardware prototype is built and experiment results also prove the concept. Finally some further developments are mentioned.
As a summary of the research a new topology and control technique were developed. The resultant circuit is a high performance transformerless PV inverter with upwards of 97% efficiency.
Traditionally, grid connected PV inverters required a transformer for isolation and safety. The disadvantage of high frequency transformer based inverters is complexity and cost. Transformerless inverters have become more popular recently, although they can be challenging to implement because of possible high frequency currents through the PV array's stay capacitance to earth ground. Conventional PV inverters also typically utilize electrolytic capacitors for bulk power buffering. However such capacitors can be prone to decreased reliability.
The solution proposed here to solve these problems is a bi directional buck boost converter combined with half bridge inverters. This configuration enables grounding of the array's negative terminal and passive power decoupling with only film capacitors.
Several aspects of the proposed converter are discussed. First a literature review is presented on the issues to be addressed. The proposed circuit is then presented and examined in detail. This includes theory of operation, component selection, and control systems. An efficiency analysis is also conducted. Simulation results are then presented that show correct functionality. A hardware prototype is built and experiment results also prove the concept. Finally some further developments are mentioned.
As a summary of the research a new topology and control technique were developed. The resultant circuit is a high performance transformerless PV inverter with upwards of 97% efficiency.
ContributorsBreazeale, Lloyd C (Author) / Ayyanar, Raja (Thesis advisor) / Karady, George G. (Committee member) / Tylavsky, Daniel (Committee member) / Tsakalis, Konstantinos (Committee member) / Arizona State University (Publisher)
Created2014