The Smart Hall at the College of Engineering, University of Baghdad, hosted a Master’s thesis defense at 9:00 AM on Thursday, September 3, 2026. The thesis was presented by researcher Rania Emad Hamdi, a student in the Department of Electrical Engineering (Power and Machines specialization), titled:
“Voltage Unbalanced Compensation in AC Microgrids Based on Distributed Control Strategy”
The thesis was submitted as part of the requirements for obtaining a Master of Science degree in Electrical Engineering, under the supervision of Prof. Dr. Firas Mohammed Tuaimah.
The study highlights reliability and sustainability solutions in modern power systems, particularly islanded AC microgrids, which serve as an effective option for integrating Distributed Energy Resources (DERs).
The researcher addresses the issue of unbalanced loads, which leads to negative-sequence voltage components. This causes power quality degradation, increased losses in power electronic converters, and reduced equipment efficiency.
To address these challenges, the study proposes two advanced hierarchical control designs:
- Primary Compensation Strategy: This strategy employs a Second-Order Generalized Integrator (SOGI) to extract positive and negative voltage components, integrating the negative sequence into the voltage control loop to achieve fast local compensation without requiring additional communication networks.
- Distributed Cooperative Secondary Control Strategy: This strategy combines SOGI technology with a Proportional-Resonant (PR) controller to coordinate voltage compensation across multiple distributed generation units, while ensuring frequency restoration, voltage regulation, and accurate active/reactive power sharing.
Simulation models conducted by the researcher using MATLAB/Simulink under various operating scenarios demonstrated significant scientific outcomes, including:
-Reduction of Voltage Unbalance Factor (VUF): The primary control design successfully reduced the VUF from 11.36% to 0.25% (a 97.8% improvement), while the distributed secondary control design lowered it from 1.9% to approximately 0.1% (a 95% improvement).
-Power Sharing Accuracy: Precise distribution of active and reactive power along with rapid dynamic response during inverter plug-and-play tests was achieved.
-Efficiency Enhancement: There was a notable drop in negative-sequence reactive power, positively reflecting on the overall operational performance of the microgrid.
The precise results obtained by the researcher are expected to open new avenues for direct practical application, particularly in supporting and developing smart, sustainable energy grids.
