AN ABSTRACT OF THE THESIS OF Ricardo Orozco for the degree of Master of Science in Electrical and Computer Engineering presented on November 3, 2011. Title: Optimal Communications System Design for Array-Based Electric Generation

approved: ______________________________________________________ Mario Edgardo Magaña The world’s demand for energy is an ongoing challenge, which has yet to be overcome. The efforts to find clean energy alternatives to fossil fuels have been hampered by the lack of investment in technology and research. Among these clean energy alternatives are ocean waves and wind. Wind power is generated through the use of wind generators that harness the wind's kinetic energy; it has gained worldwide popularity as a large-scale energy source, but only provides less than one percent of global energy consumption. Due to infrastructure limitations on installations of wind turbines at locations where high winds exist, wind energy faces critical challenges difficult to overcome to continue improving electricity generation. Ocean wave energy on the other hand seems like a promising adjunction to wind energy. Ocean energy comes in a variety of forms such as marine currents, tidal currents, geothermal vents and waves. Most of today’s research however is based on wave energy. It has been estimated that approximately 257 Terawatt hour per year (TWh/year) could be extracted from ocean waves alone. This amount of energy could be enough to meet the U.S. energy demands of 28 TWh/year. Technologies such as point absorbers, attenuators and overtopping devices are examples of wave energy converters. Point absorbers use a floating structure with components that move relative to each other due to the wave action. The relative motion is used to drive electromechanical or hydraulic energy converters. The total energy throughput of a single point absorber however, does not justify for the great engineering cost and effort by researchers. Thus the need to explore other alternatives of wave conversion that result in no extra-added cost but yet increases throughput. Our research focuses on exploring a novel method to maximize wave energy conversion of an array-based point absorber wave farm. Unlike previous research, our method incorporates a predictive control algorithm to aid the wave farm with the prediction of dynamics and optimal control trajectory over a finite time and space horizon of ocean waves. By using a predictive control algorithm, wave energy conversion throughput can be increased as opposed to a system without. This algorithm requires that the wave characteristics of the incoming wave be provided in advance for appropriate processing. This thesis focuses on designing an efficient and reliable wireless communications system capable of delivering wave information such as speed, height and direction to each point absorber in the network for further processing by the predictive control algorithm. This process takes place in the presence of harsh environmental conditions where the random shape of waves and moving surface can further affect the communication channel. In this work we focus on the physical layer where the transmission of bits over the wireless medium takes place. Specifically we are interested in reducing the bit error rate with a unique relaying protocol to increase packet transmission reliability. We make use of cooperative diversity and existing protocols to achieve our goal of merit and improve end-to-end system performance. ©Copyright by Ricardo Orozco Defense Date November 3, 2011 All Rights Reserved Optimal Communications System Design for Array-Based Electric Generation