A robust control algorithm for a multifunctional grid tied inverter to enhance the power quality of a microgrid under unbalanced conditions

• Published in: International journal of electrical power & energy systems Vol. 100; pp. 253 - 264
• Main Authors: Safa, Ahmed, Madjid Berkouk, E.L., Messlem, Youcef, Gouichiche, Abdelmadjid
• Format: Journal Article
• Language: English
• Published: Elsevier Ltd 01.09.2018
• Subjects: Microgrid; Multifunctional Grid-Tied Inverter (MFGTI); Power quality; Renewable energy source (RES); Unbalance; Unbalance; Microgrid; Power quality; Renewable energy source (RES); Multifunctional Grid-Tied Inverter (MFGTI)
• ISSN: 0142-0615; 1879-3517
• DOI: 10.1016/j.ijepes.2018.02.042

•Used a multi-functional grid connected inverter to enhance the power quality of a microgrid.•Propose a Positive Fundamental Components Estimator to extract harmonics and reactive current.•Propose a DC bus Sliding Mode Controller to enhance the dynamic of the MFGTI.•We confirmed the above advantages by experimental results.•The proposed algorithm is characterize by a low computation time, simplicity, robustness and good performances in case of unbalance. This paper proposes a robust control algorithm for a Multifunctional grid-tied inverters (MFGTI) under unbalanced load and main voltage conditions. The proposed algorithm uses the instantaneous power theory to design the MFGTI controller. A Positive Fundamental Components Estimator (PFCE) is used to estimate the undesired components of the load current such as harmonics, reactive current, and negative sequence component. The PFCE is a lightweight open loop algorithm. Hence, a good robustness is achieved with a lower computation burden. Furthermore, a new sliding mode controller (SMC) is used as a DC bus voltage regulator to enhance the dynamic performance and robustness against parameter variation. The MFGTI is connected at the Point of Common Coupling (PCC), interfacing the microgrid to the main grid. Alongside the active power injection, the proposed control algorithm allows the MFGTI to compensate reactive power, mitigate harmonics, and balance the load. Thus, the microgrid will meet the different power quality standards. An experimental prototype is designed to verify both the performance and robustness of the control algorithm. The attained results confirm the validity of the proposed algorithm.