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University of Houston
1.
Yarlagadda, Sindhu Krishna 1987-.
A MAXIMUM POWER POINT TRACKING TECHNIQUE FOR SINGLE-PHASE PHOTOVOLTAIC SYSTEMS WITH REDUCED DC-LINK CAPACITOR.
Degree: MSin Electrical Engineering, Electrical Engineering, 2012, University of Houston
URL: http://hdl.handle.net/10657/819 
► Electrolytic capacitors used in photovoltaic (PV) power conditioning units (PCU) for power decoupling purposes are less reliable in nature. Film capacitors can be adopted instead…
(more)
▼ Electrolytic
capacitors used in photovoltaic (PV) power conditioning units (PCU) for power decoupling purposes are less reliable in nature. Film
capacitors can be adopted instead of electrolytic
capacitors if the energy storage requirement of the PCU is reduced, since they offer better reliability and have a longer lifetime. The energy storage capacitor size reduction is facilitated by allowing
DC-
link voltage to have a specified amount of ripple. However, a high
DC-
link voltage ripple imposes a double-line frequency ripple in the PV panel voltage and current. This leads to oscillations in the extracted panel power and thereby results in power loss. In view of this, this thesis develops a locus line based maximum power point tracking (MPPT) control algorithm to mitigate this power loss. The proposed digital control algorithm was simulated in MATLAB Simulink and implemented in a laboratory prototype using the Digital Signal Processing (DSP)-based microcontroller, TMS320F28035.
Advisors/Committee Members: Shireen, Wajiha (advisor), Chen, Yuhua (committee member), Provence, Robert S. (committee member).
Subjects/Keywords: Maximum power point (MPP) tracking; Photovoltaics; Inverters; DC-link capacitors; Electrical engineering
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APA (6th Edition):
Yarlagadda, S. K. 1. (2012). A MAXIMUM POWER POINT TRACKING TECHNIQUE FOR SINGLE-PHASE PHOTOVOLTAIC SYSTEMS WITH REDUCED DC-LINK CAPACITOR. (Masters Thesis). University of Houston. Retrieved from http://hdl.handle.net/10657/819
Chicago Manual of Style (16th Edition):
Yarlagadda, Sindhu Krishna 1987-. “A MAXIMUM POWER POINT TRACKING TECHNIQUE FOR SINGLE-PHASE PHOTOVOLTAIC SYSTEMS WITH REDUCED DC-LINK CAPACITOR.” 2012. Masters Thesis, University of Houston. Accessed January 22, 2021.
http://hdl.handle.net/10657/819.
MLA Handbook (7th Edition):
Yarlagadda, Sindhu Krishna 1987-. “A MAXIMUM POWER POINT TRACKING TECHNIQUE FOR SINGLE-PHASE PHOTOVOLTAIC SYSTEMS WITH REDUCED DC-LINK CAPACITOR.” 2012. Web. 22 Jan 2021.
Vancouver:
Yarlagadda SK1. A MAXIMUM POWER POINT TRACKING TECHNIQUE FOR SINGLE-PHASE PHOTOVOLTAIC SYSTEMS WITH REDUCED DC-LINK CAPACITOR. [Internet] [Masters thesis]. University of Houston; 2012. [cited 2021 Jan 22].
Available from: http://hdl.handle.net/10657/819.
Council of Science Editors:
Yarlagadda SK1. A MAXIMUM POWER POINT TRACKING TECHNIQUE FOR SINGLE-PHASE PHOTOVOLTAIC SYSTEMS WITH REDUCED DC-LINK CAPACITOR. [Masters Thesis]. University of Houston; 2012. Available from: http://hdl.handle.net/10657/819
Northeastern University
2.
Chowdhury, Md Mahmud-Ul-Tarik.
A novel single-stage inverter topology.
Degree: MS, Department of Electrical and Computer Engineering, 2016, Northeastern University
URL: http://hdl.handle.net/2047/D20211266
► Inverters are considered key components to enable the integration of renewable energy sources into the grid. These power processing circuits convert dc voltage into ac,…
(more)
▼ Inverters are considered key components to enable the integration of renewable energy sources into the grid. These power processing circuits convert dc voltage into ac, and are needed in numerous applications, including residential photovoltaic (PV) systems. The state of the art inverters have several shortcomings such as limited voltage gain, low power density, high failure rates, and low efficiency.; This thesis proposes a new inverter topology that can overcome the problems associated with most conventional inverters. The proposed inverter is a single stage configuration, and employs five semiconductor switches, in which one is operating at a high frequency and the rest are operating at the fundamental frequency of the load. The proposed inverter is capable of both stepping up and stepping down the voltage. This is a unique advantage over most state of the art single-stage inverters, which can either step up or step down the voltage. In the proposed inverter, a small capacitor transfers power from the input towards the output. The inverter is designed and controlled such that the required link capacitance is very low; therefore, film capacitors that have longer lifetime compared to electrolytic capacitors can be used. Unlike most conventional isolated inverters that use low frequency transformer (LFT), in the proposed inverter a high frequency transformer (HFT) can be used for providing galvanic isolation. This feature decreases the total size of the system. The proposed inverter can be modified slightly to offer soft-switching, which significantly increases the efficiency.; In this thesis, the principles of the operation of the proposed inverter is studied, and its performance is evaluated through simulation and experiment.
Subjects/Keywords: dc-ac; inverter; link; renewable energy; Electric inverters; Design and construction; Electric current converters; Design and construction; Semiconductor switches; Capacitors; Electronic transformers; Design and construction
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APA (6th Edition):
Chowdhury, M. M. (2016). A novel single-stage inverter topology. (Masters Thesis). Northeastern University. Retrieved from http://hdl.handle.net/2047/D20211266
Chicago Manual of Style (16th Edition):
Chowdhury, Md Mahmud-Ul-Tarik. “A novel single-stage inverter topology.” 2016. Masters Thesis, Northeastern University. Accessed January 22, 2021.
http://hdl.handle.net/2047/D20211266.
MLA Handbook (7th Edition):
Chowdhury, Md Mahmud-Ul-Tarik. “A novel single-stage inverter topology.” 2016. Web. 22 Jan 2021.
Vancouver:
Chowdhury MM. A novel single-stage inverter topology. [Internet] [Masters thesis]. Northeastern University; 2016. [cited 2021 Jan 22].
Available from: http://hdl.handle.net/2047/D20211266.
Council of Science Editors:
Chowdhury MM. A novel single-stage inverter topology. [Masters Thesis]. Northeastern University; 2016. Available from: http://hdl.handle.net/2047/D20211266
Queensland University of Technology
3.
Nami, Alireza.
A new multilevel converter configuration for high power and high quality applications.
Degree: 2010, Queensland University of Technology
URL: https://eprints.qut.edu.au/33216/
► The Queensland University of Technology (QUT) allows the presentation of theses for the Degree of Doctor of Philosophy in the format of published or submitted…
(more)
▼ The Queensland University of Technology (QUT) allows the presentation of theses for the Degree of Doctor of Philosophy in the format of published or submitted papers, where such papers have been published, accepted or submitted during the period of candidature. This thesis is composed of ten published /submitted papers and book chapters of which nine have been published and one is under review. This project is financially supported by an Australian Research Council (ARC) Discovery Grant with the aim of investigating multilevel topologies for high quality and high power applications, with specific emphasis on renewable energy systems. The rapid evolution of renewable energy within the last several years has resulted in the design of efficient power converters suitable for medium and high-power applications such as wind turbine and photovoltaic (PV) systems. Today, the industrial trend is moving away from heavy and bulky passive components to power converter systems that use more and more semiconductor elements controlled by powerful processor systems. However, it is hard to connect the traditional converters to the high and medium voltage grids, as a single power switch cannot stand at high voltage. For these reasons, a new family of multilevel inverters has appeared as a solution for working with higher voltage levels. Besides this important feature, multilevel converters have the capability to generate stepped waveforms. Consequently, in comparison with conventional two-level inverters, they present lower switching losses, lower voltage stress across loads, lower electromagnetic interference (EMI) and higher quality output waveforms. These properties enable the connection of renewable energy sources directly to the grid without using expensive, bulky, heavy line transformers. Additionally, they minimize the size of the passive filter and increase the durability of electrical devices. However, multilevel converters have only been utilised in very particular applications, mainly due to the structural limitations, high cost and complexity of the multilevel converter system and control. New developments in the fields of power semiconductor switches and processors will favor the multilevel converters for many other fields of application. The main application for the multilevel converter presented in this work is the front-end power converter in renewable energy systems. Diode-clamped and cascade converters are the most common type of multilevel converters widely used in different renewable energy system applications. However, some drawbacks – such as capacitor voltage imbalance, number of components, and complexity of the control system – still exist, and these are investigated in the framework of this thesis. Various simulations using software simulation tools are undertaken and are used to study different cases. The feasibility of the developments is underlined with a series of experimental results. This thesis is divided into two main sections. The first section focuses on solving the capacitor voltage imbalance for a…
Subjects/Keywords: adjacent switching vectors, asymmetrical multilevel converter, asymmetrical diode-clamped converter, asymmetrical cascade converter, capacitor voltage imbalance, cascade converter, cross voltage control, current loop, diode-clamped converter; DC link capacitors, electromagnetic interference (EMI), hybrid cascade converter, hysteresis current control, H-bridge inverter, micro controller, multilevel converter, multi-output boost converter, multi-output DC-DC converter, over voltage, photovoltaic; planar busbar, predictive current control, pulse width modulation (PWM), renewable energy systems, stray inductance, switching components, switching losses, voltage stress, voltage sharing converter, wind turbine
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APA (6th Edition):
Nami, A. (2010). A new multilevel converter configuration for high power and high quality applications. (Thesis). Queensland University of Technology. Retrieved from https://eprints.qut.edu.au/33216/
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):
Nami, Alireza. “A new multilevel converter configuration for high power and high quality applications.” 2010. Thesis, Queensland University of Technology. Accessed January 22, 2021.
https://eprints.qut.edu.au/33216/.
Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation
MLA Handbook (7th Edition):
Nami, Alireza. “A new multilevel converter configuration for high power and high quality applications.” 2010. Web. 22 Jan 2021.
Vancouver:
Nami A. A new multilevel converter configuration for high power and high quality applications. [Internet] [Thesis]. Queensland University of Technology; 2010. [cited 2021 Jan 22].
Available from: https://eprints.qut.edu.au/33216/.
Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation
Council of Science Editors:
Nami A. A new multilevel converter configuration for high power and high quality applications. [Thesis]. Queensland University of Technology; 2010. Available from: https://eprints.qut.edu.au/33216/
Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation
Indian Institute of Science
4.
Gopalakrishnan, K S.
Study On DC-Link Capacitor Current In A Three-Level Neutral-Point Clamped Inverter.
Degree: MSc Engg, Faculty of Engineering, 2017, Indian Institute of Science
URL: http://etd.iisc.ac.in/handle/2005/2628
► Three-level diode-clamped inverter is being widely used these days. Extensive research has been carried out on pulse width modulation (PWM) strategies for a three-level inverter.…
(more)
▼ Three-level diode-clamped inverter is being widely used these days. Extensive research has been carried out on pulse width modulation (PWM) strategies for a three-level inverter. The most widely used PWM strategies are sine-triangle pulse width modulation (SPWM) and centered space vector pulse width modulation (CSVPWM). The influence of these PWM strategies on the
DC-
link capacitor current and voltage ripple is studied in this thesis.
The sizing of the
DC capacitor depends on value of the maximum RMS current flowing through it. In this work, an analytical expression for capacitor RMS current is derived as a function of operating conditions like modulation index, power factor angle of the load and peak load current. The worst case current stress on the capacitor is evaluated using the analytical expression. The capacitor RMS current is found to be the same in SPWM and CSVPWM schemes. The analytical expression is validated through simulations and experiments on a 3kVA MOSFET based three-level inverter.
Harmonic analysis of the capacitor current is helpful in better evaluation of capacitor power loss. Therefore, harmonic analysis of the capacitor current is carried out, using the techniques of geometric wall model and double Fourier integral for SPWM and CSVPWM schemes. The theoretical predictions are validated through experiments.
The capacitor RMS current is divided into low-frequency RMS current (where low frequency component is defined as a component whose frequency is less than half the switching frequency) and high-frequency RMS current. The capacitor voltage ripple is estimated analytically for SPWM and CSVPWM schemes, using the low-frequency and high-frequency capacitor RMS current. The voltage ripples due to SPWM and CSVPWM schemes are compared. It is found that the voltage ripple with SPWM is higher than that with CSVPWM. A simplified method to estimate the capacitor power loss, without the requirement of FFT analysis of capacitor current, is proposed. The results from this simplified method agree reasonably well with the results from the detailed method.
A space vector based modulation scheme is proposed, which reduces the capacitor RMS current at high power factor angles. However, the proposed method leads to higher total harmonic distortion (THD) than CSVPWM. Simulation and experimental results, comparing CSVPWM and the proposed PWM, are presented.
Advisors/Committee Members: Narayanan, G (advisor).
Subjects/Keywords: Voltage Source Inverters; Electrolytic Capacitors; Capacitor Current; Electric Inverters; Pulse Width Modulation (PWM); Dc-Link Capacitor Current; DC Electrolytic Capacitor; Space-Vector Pulse Width Modulation; Capacitor Power Loss; Capacitor Voltage Ripple; Capacitor RMS (Root Mean Square) Current; Centered Space Vector Pulse Width Modulation (CSVPWM); Diode Clamped Inverters; Sine-triangle Pulse Width Modulation (SPWM); RMS Current; Three-Level Diode-Clamped Inverters; Diode-clamped VSI; Power Electronics
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APA ·
Chicago ·
MLA ·
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CSE |
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to Zotero / EndNote / Reference
Manager
APA (6th Edition):
Gopalakrishnan, K. S. (2017). Study On DC-Link Capacitor Current In A Three-Level Neutral-Point Clamped Inverter. (Masters Thesis). Indian Institute of Science. Retrieved from http://etd.iisc.ac.in/handle/2005/2628
Chicago Manual of Style (16th Edition):
Gopalakrishnan, K S. “Study On DC-Link Capacitor Current In A Three-Level Neutral-Point Clamped Inverter.” 2017. Masters Thesis, Indian Institute of Science. Accessed January 22, 2021.
http://etd.iisc.ac.in/handle/2005/2628.
MLA Handbook (7th Edition):
Gopalakrishnan, K S. “Study On DC-Link Capacitor Current In A Three-Level Neutral-Point Clamped Inverter.” 2017. Web. 22 Jan 2021.
Vancouver:
Gopalakrishnan KS. Study On DC-Link Capacitor Current In A Three-Level Neutral-Point Clamped Inverter. [Internet] [Masters thesis]. Indian Institute of Science; 2017. [cited 2021 Jan 22].
Available from: http://etd.iisc.ac.in/handle/2005/2628.
Council of Science Editors:
Gopalakrishnan KS. Study On DC-Link Capacitor Current In A Three-Level Neutral-Point Clamped Inverter. [Masters Thesis]. Indian Institute of Science; 2017. Available from: http://etd.iisc.ac.in/handle/2005/2628
. 
Open Access Theses and Dissertations