Engineering Commons^™

Impedance-Based Stability Analysis And Controller Design Of Three-Phase Inverter-Based Ac Systems, Wenchao Cao

Doctoral Dissertations

Three-phase voltage-source power inverters are widely used for energy conversion in three-phase ac systems, such as renewable energy systems and microgrids. These three-phase inverter-based ac systems may suffer from small-signal instability issues due to the dynamic interactions among inverters and passive components in the systems. It is crucial for system integrators to analyze the system stability and design the inverter controller parameters during system planning and maintenance periods to guarantee stable system operation. The impedance-based approach can analyze the stability of source-load systems, by applying the Nyquist stability criterion or the generalized Nyquist stability criterion (GNC) to the impedance ratio …

Three-Phase Power Converter Based Real-Time Synchronous Generator Emulation, Liu Yang

Doctoral Dissertations

To bridge the gap between power system research and their real application in power grids, a Hardware Test-Bed (HTB) with modular three-phase power converters has been developed at the CURENT center, the University of Tennessee, Knoxville, to emulate transmission level power systems with actual power flowing.

This dissertation focuses on the development and verification of a real-time synchronous generator (SG) emulator in the HTB. The research involved in this dissertation aims at designing a proper control to achieve emulator performance goal and investigating the sources of error and its influence on interconnected SG-emulator networks.

First, different interface algorithms (IAs) are …

Microgrid Modeling And Grid Interconnection Studies, Hira Amna Saleem

Masters Theses

The demand for renewable energies and their integration to the grid has become more pressing than ever before due to the various reasons including increasing population energy demand, depleting fossil fuels, increasing atmospheric population, etc. Thus the vision of a sustainable future requires easy and reliable integration of renewable distributed generators to the grid. This master’s thesis studies the dynamics of distributed generators when they are connected with the main grid. Simulink MATLAB is used for the design and simulations of this system. Three distributed generators are used in this system: Photo-voltaic converter, Fuel cell and diesel generator. The control …