"An approach to modeling externally controlled inverters in droop controlled microgrids is presented. A generic three-phase grid-tied inverter and control system model is derived in synchronous reference frame. The structure of this inverter is intended to be similar in composition to other three-phase inverters whose models and dynamics are well understood. This model is used as a starting point in the development of a more comprehensive model, which is capable of representing the coupling between complex power, bus voltage, and frequency that occurs in a microgrid. This new model is a combination of the generic inverter and an autonomous, grid-forming inverter with a local load. The accuracy of the new model is verified through comparisons of small-signal dynamic predictions, simulations, and experimental results from a microgrid testbed.
The proposed procedure of modifying an existing small-signal model for use in a microgrid system retains the information of the original model while successfully enabling the prediction of dynamic interactions with other generating units in the microgrid. The process is scalable for any number of inverters at the same point of connection, allowing accurate predictions of full system dynamics during distributed control actions, such as black start or grid-resynchronization. Traditional linear control techniques may be used to improve the performance and stability of the microgrid system. This is a demonstrated in an analysis of the system's eigenvalues. Drawing from the insights provided by this analysis, hardware and control parameters are selected to improve the response of the generic inverter"--Abstract, page iii.
Kimball, Jonathan W.
Electrical and Computer Engineering
M.S. in Electrical Engineering
United States. Department of Energy
Missouri University of Science and Technology
ix, 54 pages
© 2014 Jacob Andreas Mueller, All rights reserved.
Thesis - Open Access
Distributed generation of electric power
Smart power grids
Electronic OCLC #
Mueller, Jacob Andreas, "Small-signal modeling of grid-supporting inverters in droop controlled microgrids" (2014). Masters Theses. 7335.