Document Type



Doctor of Philosophy (PhD)


Electrical and Computer Engineering

First Advisor's Name

Arif Sarwat

First Advisor's Committee Title

Committee chair

Second Advisor's Name

Jean H. Andrian

Second Advisor's Committee Title

Committee member

Third Advisor's Name

Sumit Paudyal

Third Advisor's Committee Title

Committee member

Fourth Advisor's Name

Berrin Tansel

Fourth Advisor's Committee Title

Committee member

Fifth Advisor's Name

Deepal Rodrigo

Fifth Advisor's Committee Title

Committee member


Distributed Energy Resources, Inverter Control, Resilience, Critical Infrastructure

Date of Defense



Efforts towards decarbonized economy has added new pressures in the distribution network, especially with increased penetration of distributed generation, electrification of transportation, etc. It demands breakthrough technologies to be developed in different sectors such as in power systems, power electronics, communication, among others. The work of this dissertation investigates a twofold approach of distribution energy resources (DERs) implementation to address the challenges faced by modern power distribution network. The first approach is to develop advance control techniques for smart inverters that interlinks DERs to the grid to facilitate grid support services. A complexity reduced finite control set model predictive direct power controller (FS-MPDPC) for active-reactive bidirectional power control of grid connected converter has been developed. This avoids the brute-force search inherent to FS-MPDC which cut down the computational complexity. Further, a fuzzy decision making (FDM) assisted MPDPC (fuzzy-MPDPC) is derived for a three-phase grid-connected converter that interlinks battery energy storage system (BESS) to the grid. The controller combines fuzzy logic and MPDPC theories to control bidirectional active, reactive power. Rather than using a layered control architecture for BESS scheduling and grid feed control, this work proposes an improved model predictive controller with fuzzy goal, fuzzy-constraint based objective function which dynamically adjusts according to external conditions. The second approach is to develop resilience enhancement and quantification techniques for power distribution network. For that, an algorithm is formulated for optimal hosting and placement of DERs for network resiliency enhancement. This multi-objective nonlinear programming formulation incorporates a unique critical load (CL) ranking scheme to prioritize the CL nodes for the DER placement while achieving a maximum DER hosting capacity, improving resiliency and minimizing the system's active power loss while satisfying all network and power flow constraints. The developed algorithm is validated for different outage scenarios caused by a hurricane and the results verify the effectiveness. Secondly, a metric scheme has been developed to quantify the level of resilience of the network and to justify the resilience enhancements done on the system. The metrics are validated by showcasing the resilience enhancement before and after implementation of DERs through the metrics.





Previously Published In

Dharmasena, S., Olowu, T.O., Sarwat, A.I.: A low-compl exity FS-MPDPC with extended voltage set for grid-connected converters. IET Energy Syst. Integr. 3( 4), 413– 425 (2021).

S. Dharmasena and A. I. Sarwat, "Fuzzy Decision Making Assisted Model Predictive Direct Power Controller for a Grid-Interlinking Converter of a Battery Energy Storage System," 2020 52nd North American Power Symposium (NAPS), 2021, pp. 1-6, doi: 10.1109/NAPS50074.2021.9449778.

S. Dharmasena, T. O. Olowu and A. I. Sarwat, "Algorithmic Formulation for Network Resilience Enhancement by Optimal DER Hosting and Placement," in IEEE Access, vol. 10, pp. 23477-23488, 2022, doi: 10.1109/ACCESS.2022.3154056.

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