AC Microgrids, in presence of highly non-linear loads, require a tighter regulation of line voltage to maintain power quality. This article proposes an outer virtual impedance loop to shape the output voltage in such microgrids. In order to achieve this, a virtual impedance extracting and shaping filter is first proposed to extract and weigh selected frequency components of the line current. Secondly, design of impedances to weigh the extracted frequency components is obtained in order to achieve harmonic current sharing and reducing total harmonic distortion (THD) even in scenarios of asymmetric sharing of highly non-linear loads. An isochronous voltage-active power half droop architecture is also employed to achieve active, reactive power sharing and to keep circulating currents minimum in the low-voltage microgrid. Analytical results on designing virtual impedances and their dependence on network line parameters are obtained. Finally, MATLAB/SIMULINK-based simulations are performed on a 4.4 kVA microgrid and implemented on a low-cost controller in a controller-hardware-in-the-loop (CHIL) setup to validate the viability of implementation and efficacy of the proposed virtual impedance shaping method.
|Original language||English (US)|
|Title of host publication||APEC 2020 - 35th Annual IEEE Applied Power Electronics Conference and Exposition|
|Publisher||Institute of Electrical and Electronics Engineers Inc.|
|Number of pages||8|
|State||Published - Mar 2020|
|Event||35th Annual IEEE Applied Power Electronics Conference and Exposition, APEC 2020 - New Orleans, United States|
Duration: Mar 15 2020 → Mar 19 2020
|Name||Conference Proceedings - IEEE Applied Power Electronics Conference and Exposition - APEC|
|Conference||35th Annual IEEE Applied Power Electronics Conference and Exposition, APEC 2020|
|Period||3/15/20 → 3/19/20|
Bibliographical noteFunding Information:
ACKNOWLEDGMENT The authors acknowledge Advanced Research Projects Agency-Energy (ARPA-E) NODES for supporting this research through the project titled ”A Robust Distributed Frame-work for Flexible Power Grids” via grant no. DE-AR0000701 and Xcel Energy’s Renewable Development Fund.
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