Future all-electric warships with an integrated power system (IPS) are capable of unlocking large amounts of power dedicated to propulsion and redirecting this power for service loads, weapon loads, and other loads. The IPS for all-electric ships combines the power generation system, electric propulsion system, power distribution system, and power control and management system all together. The move to IPS design will significantly improve efficiency, effectiveness, and survivability. To meet the needs of the US Navy, enhancing survivability by reducing susceptibility to damage, a IPS prefers decentralized reconfiguration system is preferred for IPS instead of traditional reconfiguration techniques used for terrestrial power grids. A multi-agent system (MAS) is a loosely coupled network composed of several agents. These agents interact with their environments and communicate with each other to solve problems that are beyond the individual capabilities or knowledge of each single agent. Because of its decentralized feature and lack of a global control feature, MAS appears to be the best candidate for IPS reconfiguration. This research work proposes a new model of an IPS, based on the Naval Combat Survivability, DC Distribution Test-bed (NCS DCDT). The new model combines the electric power generation system, electric propulsion system, and AC-DC zonal distribution system. To decrease the probability of distribution zones losing power, the new model modifies original design of the zonal distribution system in NCS DCDT. Another main endeavor of this research work is to design a MAS for reconfiguration of an IPS with AC-DC zonal distribution system. The MAS consists of three sub-MAS, named power generation MAS, propulsion MAS, and distribution MAS, and includes forty-one different agents which are instances of nineteen different abstract agent classes. The MAS is implemented with JAVA/JADE software and simulated on a platform of JADE 3.4.1 and JAVA jdk 1.5.0_08. Simulation results show that the MAS can execute reconfiguration functions such as fault area isolation, automatic switching, and load shedding.

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This thesis describes the design of multivariable excitation controllers for synchronous generators, and their practical implementation on a laboratory machine system. The main objectives of the investigation were aimed at extending the steady-state stability limit of the generator and improving its general controllability. The present work is principally concerned with the implementation and test of the designs. Instrumentation has been developed to measure and combine feedback signals; this instrumentation and the laboratory generator system are described in detail. The performances of the controllers are predicted by computer simulation and evaluated by practical testing; attention is focussed on comparison of predicted and experimental performances. The theoretical basis of the design strategy is described, in which an optimal control algorithm applies the system states as feedback signals to the open-loop system, thereby shifting certain of the system eigenvalues to more desirable, predetermined locations. The state variables are selected as physically measurable quantities which obviates the need for implementing state estimation techniques.

In this thesis a robust nonlinear tracking is proposed for a class of single machine connected to an infinite bus (SMIB) systems. Designing of the controller is based on the backstepping control technique, where designer interlaces the choice of L yapunov functions in order to design the controller and analyze the stability of the power angle and rotating speed of the generator. Nonlinear models are considered directly in the designing process, hence neglecting the effects of nonlinear terms in the plant can be avoided, which may also improve the robustness of controlled system¡¦s transient stability. In order to enhance the applicability of the proposed control scheme, the perturbations that may encountered in the system are considered, and adaptive laws are embedded in the controllers so that the upper bound of perturbations need not to be known beforehand. Two numerical examples are given to illustrate the feasibility of the proposed control scheme.

This thesis designs a DSP-based controller which is composed of two parts,voltage controller and current controller.A proportional controller,treated as the current controller,is designed in the inner loop to control the capacitor charging current fast and effectively,especially when the sudden load is occurred.An PI controller,treated as the voltage controller,is designed in the outer loop to improve the system response irrespectively of system¡¦s parameter variation and load disturbance.The experimental result shows the output voltage can follow a sin wave which can match command exactly under the control scheme.

This paper investigates the concept of an isolated small wind power system based on a three-phase generator and a direct ac-to-ac conversion. The ac-to-ac conversion is performed by a matrix converter and thus removing the need of a large smoothing capacitor in the typical rectifier-inverter solution. The paper is briefly presenting the operation for a particular topology of a three-phase to single-phase matrix converter. The control of this conversion ensures system’s frequency and voltage stability. Simulation results and practical results are presented to validate the frequency and voltage regulation of the isolated power system.

published_or_final_version / Electrical and Electronic Engineering / Master / Master of Philosophy