Control Design and Experimental Validation of a Scalable Single-Phase Islanded AC Microgrid Testbed for Research and Education

This paper presents a research and educational tool for islanded AC microgrids. High penetration of renewable energy can cause instability in traditional power grids. Microgrid technology addresses this by effectively integrating local renewable sources, managing energy through intelligent coordination, and can support the main power grid. However, obtaining test beds for research and education remains challenging due to system complexity, cost, and limited scalability in existing solutions. In this paper, the hierarchical control design of an islanded AC microgrid, which includes inner loop Proportional-Resonant controllers for voltage regulation, Phase-Locked Loop-based synchronization, virtual impedance for decoupling active and reactive powers, droop control for power sharing, and a secondary controller for voltage and frequency restoration as well as reactive power compensation is detailed. The experimental setup consists of two distributed generators (inverters) feeding linear and nonlinear loads. It is controlled by a dSPACE platform, with STMF4 Discovery microcontrollers generating Pulse-Width-Modulation signals to reduce the computational burden on dSPACE and facilitate scalability. Experimental results demonstrate that the testbed maintains stable operation under various load conditions, achieves proper power sharing, and restores the microgrid’s frequency and voltage to predefined levels. Its modular design supports future expansion for both research and teaching, enabling hands-on experimentation and analysis.