Engineering Commons^™

Control Of Modular Multilevel Converters For Grid Integration Of Full-Scale Wind Energy Conversion Systems, Suman Debnath

Open Access Dissertations

The growing demand for wind power generation has pushed the capacity of wind turbines towards MW power levels. Higher capacity of the wind turbines necessitates operation of the generators and power electronic conversion systems at higher voltage/power levels. The power electronic conversion system of a wind energy conversion system (WECS) needs to meet the stringent requirements in terms of reliability, efficiency, scalability and ease of maintenance, power quality, and dv/dt stress on the generator/transformer. Although the multilevel converters including the neutral point clamped (NPC) converter and the active NPC converter meet most of the requirements, they fall short in reliability …

Overcoming Fundamental Barriers In Photovoltaic And Terahertz Generation, Chao Zhou

Open Access Theses

Several fundamental barriers limit the performance of opto-electronic conversion processes below 100%. Two specific examples of current technological interest include photovoltaic conversion of sunlight into electricity (i.e., solar cells), and terahertz generation from optical sources. In particular, solar cells are limited not only by the Carnot limit associated with the second law (approximately 86% at room temperature), but also by radiative recombination, non-reciprocity, carrier thermalization, and sub-bandgap losses. In the case of terahertz generation, the typical process of difference frequency generation relies on two input optical waves with only a small difference between them to generate the desired output; however, …

Synthesizing Bismuth Telluride Nanowires In A Large Scale And Investigating The Energy Filtering Effect By Blending Bismuth Telluride Nanowires And Silver Nanoparticle In Thermoelectrics, Henka Darsono, Haiyu Fang, Yue Wu

The Summer Undergraduate Research Fellowship (SURF) Symposium

More than 50% of the energy sources becomes “waste” energy generally dissipated to the atmosphere in the form of heat. Thermoelectric effect is a conversion of temperature difference to electric voltage and can be used to convert the wasted heat to useful work. Nanomaterials have great potentials in the field of thermoelectric effect since they have properties that can allow higher efficiency in converting this wasted heat to electricity as compared to bulk materials. The purpose of this project is to develop a method to synthesize bismuth telluride (Bi₂Te₃) nanowires on a large scale and incorporate …

Solar Cell Temperature Dependent Efficiency And Very High Temperature Efficiency Limits, John Robert Wilcox

Open Access Dissertations

Clean renewable solar energy is and will continue to be a critically important source of electrical energy. Solar energy has the potential of meeting all of the world's energy needs, and has seen substantial growth in recent years. Solar cells can convert sun light directly into electrical energy, and much progress has been made in making them less expensive and more efficient. Solar cells are often characterized and modeled at 25 °C, which is significantly lower than their peak operating temperature. In some thermal concentrating systems, solar cells operate above 300 °C. Since increasing the temperature drastically affects the terminal …

Assessing The Engineering Performance Of Affordable Net-Zero Energy Housing, Jordan P. Wallpe

Purdue Polytechnic Masters Theses

The purpose of this research was to evaluate affordable technologies that are capable of providing attractive, cost-effective energy savings to the housing industry. The research did so by investigating the 2011 Solar Decathlon competition, with additional insight from the Purdue INhome. Insight from the Purdue INhome verified the importance of using a three step design process to design a net-zero energy building. In addition, energy consumption values of the INhome were used to compare and contrast different systems used in other houses.

Evaluation of unbiased competition contests gave a better understanding of how a house can realistically reach net-zero. Upon …