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You searched for subject:(THD reduction). Showing records 1 – 2 of 2 total matches.

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Virginia Tech

1. Zhang, Di. Analysis and Design of Paralleled Three-Phase Voltage Source Converters with Interleaving.

Degree: PhD, Electrical and Computer Engineering, 2010, Virginia Tech

Three-phase voltage source converters(VSCs) have become the converter of choice in many ac medium and high power applications due to their many advantages, including low harmonics, high power factor, and high efficiency. Modular VSCs have also been a popular choice as building blocks to achieve even higher power, primarily through converter paralleling. In addition to high power ratings, paralleling converters can also provide system redundancy through the so-called (N+1) configuration for improved availability, as well as allow easy implementation of converter power management. Interleaving can further improve the benefit of paralleling VSCs by reducing system harmonic currents, which potentially can increase system power density. There are many challenges to implement interleaving in paralleled VSCs system due to the complicated relationships in a three-phase power converter system. In addition, to maximize the benefit of interleaving, current knowledge of symmetric interleaving is not enough. More insightful understanding of this PWM technology is necessary before implement interleaving in a real paralleled VSCs system. In this dissertation, a systematic methodology to analyze and design a paralleled three-phase voltage source converters with interleaving is developed. All the analysis and proposed control methods are investigated with the goal of maximizing the benefit of interleaving based on system requirement. The dissertation is divided into five sections. Firstly, a complete analysis studying the impact of interleaving on harmonic currents in ac and dc side passive components for paralleled VSCs is presented. The analysis performed considers the effects of modulation index, pulse-width-modulation (PWM) schemes, interleaving angle and displacement angle. Based on the analysis the method to optimize interleaving angle is proposed. Secondly, the control methods for the common mode (CM) circulating current of paralleled three-phase VSCs with discontinuous space-vector modulation (DPWM) and interleaving are proposed. With the control methods, DPWM and interleaving, which is a desirable combination, but not considered possible, can be implemented together. In addition, the total flux of integrated inter-phase inductor to limit circulating current can be minimized. Thirdly, a 15 kW three phase ac-dc rectifier is built with SiC devices. With the technologies presented in this dissertation, the specific power density can be pushed more than 2kW/lb. Fourthly, the converter system with low switching frequency is studied. Special issues such as beat phenomenon and system unbalance due to non-triplen carrier ratio is explained and solved by control methods. Other than that, an improved asymmetric space vector modulation is proposed, which can significantly reduce output current total harmonic distortion (THD) for single and interleaved VSCs system. Finally, the method to protect a system with paralleled VSCs under the occurrence of internal faults is studied. After the internal fault is detected and isolated,… Advisors/Committee Members: Centeno, Virgilio A. (committee member), Leech, Irene E. (committee member), De La Ree Lopez, Jaime (committee member), Boroyevich, Dushan (committeecochair), Wang, Fei Fred (committeecochair).

Subjects/Keywords: passive component minimization; high power density; Asymmetric interleaving angle; harmonic current reduction; Asymmetric SVM; Interleaving; THD reduction; failure mode analysis

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APA · Chicago · MLA · Vancouver · CSE | Export to Zotero / EndNote / Reference Manager

APA (6th Edition):

Zhang, D. (2010). Analysis and Design of Paralleled Three-Phase Voltage Source Converters with Interleaving. (Doctoral Dissertation). Virginia Tech. Retrieved from http://hdl.handle.net/10919/27579

Chicago Manual of Style (16th Edition):

Zhang, Di. “Analysis and Design of Paralleled Three-Phase Voltage Source Converters with Interleaving.” 2010. Doctoral Dissertation, Virginia Tech. Accessed April 25, 2019. http://hdl.handle.net/10919/27579.

MLA Handbook (7th Edition):

Zhang, Di. “Analysis and Design of Paralleled Three-Phase Voltage Source Converters with Interleaving.” 2010. Web. 25 Apr 2019.

Vancouver:

Zhang D. Analysis and Design of Paralleled Three-Phase Voltage Source Converters with Interleaving. [Internet] [Doctoral dissertation]. Virginia Tech; 2010. [cited 2019 Apr 25]. Available from: http://hdl.handle.net/10919/27579.

Council of Science Editors:

Zhang D. Analysis and Design of Paralleled Three-Phase Voltage Source Converters with Interleaving. [Doctoral Dissertation]. Virginia Tech; 2010. Available from: http://hdl.handle.net/10919/27579


Texas A&M University

2. Alhuwaishel, Fahad. The New Active Output Filter for Variable Speed Constant Frequency Aerospace Applications.

Degree: 2015, Texas A&M University

A concept called ?Active Output Filter? (AOF) for performing output filtering in switching converter is proposed. The methodology is based on voltage harmonic injection via a combination of H Bridge and minimized LC filter to cancel out the odd harmonics from a 400Hz square wave 3 phase inverter to achieve a pure sinusoidal output with modulation index of 1.27. Investigation reveals that AOF allows a substantial size reduction and gives competitive efficiency, as compared to passive inductor capacitor filter. Moreover, the main square wave inverter has a capability to regulate the output voltage depending on the Load requirements providing a wide range of modulation index. The operation principle of the concept is demonstrated for Variable Speed Constant Frequency (VSCF) high power aircraft application. The exploration lays a foundation for further investigation into the use of AOF concept for other power electronic converter systems. Advisors/Committee Members: Enjeti, Prasad (advisor), Ehsani, Mehrdad (Mark) (committee member), Bhattarcharya, Shanker P. (committee member), Daripa, Prabir (committee member).

Subjects/Keywords: Active Output Filter; AOF; Size reduction, Three phase; Single Phase; modulation index of 1.27; LOW THD, harmonic voltage injection, self balancing capacitors; voltage control; SHEPWM; SVPWM

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APA · Chicago · MLA · Vancouver · CSE | Export to Zotero / EndNote / Reference Manager

APA (6th Edition):

Alhuwaishel, F. (2015). The New Active Output Filter for Variable Speed Constant Frequency Aerospace Applications. (Thesis). Texas A&M University. Retrieved from http://hdl.handle.net/1969.1/155540

Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation

Chicago Manual of Style (16th Edition):

Alhuwaishel, Fahad. “The New Active Output Filter for Variable Speed Constant Frequency Aerospace Applications.” 2015. Thesis, Texas A&M University. Accessed April 25, 2019. http://hdl.handle.net/1969.1/155540.

Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation

MLA Handbook (7th Edition):

Alhuwaishel, Fahad. “The New Active Output Filter for Variable Speed Constant Frequency Aerospace Applications.” 2015. Web. 25 Apr 2019.

Vancouver:

Alhuwaishel F. The New Active Output Filter for Variable Speed Constant Frequency Aerospace Applications. [Internet] [Thesis]. Texas A&M University; 2015. [cited 2019 Apr 25]. Available from: http://hdl.handle.net/1969.1/155540.

Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation

Council of Science Editors:

Alhuwaishel F. The New Active Output Filter for Variable Speed Constant Frequency Aerospace Applications. [Thesis]. Texas A&M University; 2015. Available from: http://hdl.handle.net/1969.1/155540

Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation

.