Abstract
This paper develops and compares two control schemes in the application control layer of a non-phase-locked loop (non-PLL) grid-forming (GFM) inverter to gain insight and understanding into how the two schemes affect the dynamic responses of GFM inverters and the transition operation of microgrids. The first scheme adopts power tracking based on an outer current loop in grid-connected mode and droop control in islanded mode, and the second uses droop control in both grid-connected and islanded modes. Analytical study is developed to compare the performance of these two strategies from various aspects, including fundamental differences, transition operation, power tracking, and P-Q capability with low point-of-common-coupling (PCC) voltages. Extensive simulation testing is carried out to validate the control performance of these two control strategies, and the simulation testing confirms the findings of the analytic study. Finally, the second strategy is recommended because of its superior control performance and ease of implementation. The analysis and results are useful in developing reliable control schemes for non-PLL GFM inverters because increasing numbers of inverters will work as non-PLL grid-forming sources in future grids because of their improved stability and reliability.
Original language | American English |
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Pages | 1079-1086 |
Number of pages | 8 |
DOIs | |
State | Published - 2021 |
Event | 13th IEEE Energy Conversion Congress and Exposition, ECCE 2021 - Virtual, Online, Canada Duration: 10 Oct 2021 → 14 Oct 2021 |
Conference
Conference | 13th IEEE Energy Conversion Congress and Exposition, ECCE 2021 |
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Country/Territory | Canada |
City | Virtual, Online |
Period | 10/10/21 → 14/10/21 |
Bibliographical note
See NREL/CP-5D00-78874 for preprintNREL Publication Number
- NREL/CP-5D00-82059
Keywords
- grid-forming inverter
- P-Q capability
- power tracking
- smooth microgrid transition operation