A joint framework of design, control, and applications of energy generation and energy storage systems

8/28/2014This dissertation focuses on the design and runtime control of advanced electrical energy generation and storage systems for a wide range of applications, from the power grid to electric cars, and from households to mobile battery‐operated devices. The dissertation is organized in three parts, focusing on energy generation, energy storage, and their integration and applications. ❧ Due to an increasing appetite for energy and concern about environmental impacts of fossil fuels, there has been a growing demand for renewable, eco‐friendly and sustainable energy resources (e.g., solar, wind, geothermal). The energy produced from these alternate energy resources must be cost‐competitive with the energy produced from fossil fuels. Photovoltaic (PV) energy generation techniques have received significant attention since they utilize the abundance of solar energy and can be easily scaled up. A PV system is comprised of several (series‐connected) PV modules, an energy storage, and charger connecting in between. Accurate modeling and effective control of the PV system is mandatory in order to fully exploit the solar irradiance. Moreover, PV systems are subject to the partial shading effect that can result in a significant degradation in the PV system output power. ❧ The first part of this dissertation presents an accurate modeling framework of each component in the PV system and an effective control mechanism, called the maximum power transfer tracking method. In addition, a cost‐effective reconfigurable PV architecture to combat the partial shading effect and a dynamic programming‐based reconfiguration algorithm to maximize the overall PV system output power are described. Experimental results based on a hardware prototype of a reconfigurable PV system demonstrate the accuracy of the PV modeling and the effectiveness of the PV reconfiguration algorithm. Moving towards real testbeds, this dissertation next focuses on how the aforesaid reconfigurable PV system can be integrated into a hybrid electric vehicle (HEV) so as to maximize the total distance which is travelled by an HEV on a full tank of gasoline with the aid of the PV harvested energy. The issue of capital cost and economic vialibilty of the proposed reconfigurable PV system is considered next. ❧ As of today, no single type of EES (electrical energy storage) element, e.g., batteries, supercapacitors, can fulfill all desirable features of an ideal storage device. In this dissertation the architecture and control mechanisms for a hybrid EES (HEES) system comprising of two or more heterogeneous EES elements are presented. The HEES system, which can realize advantages of each EES element while hiding their weaknesses, can thus exhibit superior performance compared to conventional homogeneous EES systems. Three fundamental charge management policies are defined in this dissertation: charge allocation from a power source to a set of EES banks, charge replacement from EES banks to load devices, and charge migration among EES banks to improve the availability and responsiveness of the HEES system. In particular, an optimal control policy for charge migration and algorithms for fault detection and tolerance in the HEES system are presented. Finally, a state‐of‐health (SoH) aware joint charge management algorithm for the HEES system, which is based on an improved SoH modeling, is discussed. ❧ The last part of this dissertation focuses on joint control and applications of the proposed (reconfigurable) PV and HEES systems. The target platforms range from residential units to portable embedded systems. It has been observed that both the appropriate system design and runtime control algorithm are critical in order to enhance the energy efficiency