Inrush Current Mitigation for Grid-Forming Inverters in Islanded Microgrids

Conference · Sun Oct 09 04:00:00 EDT 2022 · 2022 IEEE Energy Conversion Congress and Exposition (ECCE)

DOI:https://doi.org/10.1109/ecce50734.2022.9948063· OSTI ID:1905744

Gursoy, Mehmetcan ^[1]; Mirafzal, Behrooz ^[2]

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1. Kansas State University,Department of Electrical and Computer Engineering,Manhattan,KS,USA; Kansas State University
2. Kansas State University,Department of Electrical and Computer Engineering,Manhattan,KS,USA

Virtual-inertia and droop control methods are commonly used for grid-forming inverters. While the virtual inertia is used to emulate the equation of motion/frequency, if the inverter output voltage is emulated as in synchronous generators, then the method is known as the virtual synchronous generator. An inductive pulse-load, e.g., a relatively large induction motor, connection to a microgrid fed only by grid-forming inverters may lead to blackout due to high inrush currents. This article presents virtual reactance techniques to mitigate the inrush current effects and enhance the inverter’s robustness for the safe connection of inductive and dynamic loads. This article also compares the virtual inertia and droop control methods under switching inductive-dynamic loads while the proposed techniques are implemented. Experimental tests are performed considering the linear and nonlinear virtual reactance techniques, and the findings are discussed. The mitigation significantly suppresses the inrush currents while the inverters can perform a normal operation. Furthermore, the frequency and power response of the virtual inertia control with different inertia settings to a sudden change in the load is analyzed. The virtual reactance technique is tested in a laboratory-scale hardware setup of a 208V microgrid fed by 5kVA and 10kVA inverters, and the results are presented in this article.

• Research Organization: Kansas State University
• Sponsoring Organization: USDOE Office of Energy Efficiency and Renewable Energy (EERE), Renewable Power Office. Solar Energy Technologies Office
• DOE Contract Number: EE0008767
• OSTI ID: 1905744
• Report Number(s): DOE-KSU-8767
• Conference Information: Journal Name: 2022 IEEE Energy Conversion Congress and Exposition (ECCE)
• Country of Publication: United States
• Language: English