Abstract
This article proposes a grid-forming based decoupling approach, which effectively mitigates the dynamic interactions between active and reactive power, especially suitable for system stabilization in ultrastrong grids with short-circuit ratio over 30. The physical coupling behaviors are first revealed by analytical studies, where two potential resonances, respectively, located in 40-50 Hz and 0-10 Hz are discovered with mathematical proofs. Based on the results, the decoupling controller is then designed with transfer function approximation for practical usage. The control method not only suppresses the couplings but also cancels two pairs of conjugate poles through decoupling paths. Thanks to the cancellation, the stability margin is remarkably increased in stiff grids, and therefore, a significant bandwidth boost on the power synchronization control can be realized if desired. The experimental results are finally performed to verify the proposed decoupling method.
Original language | English |
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Journal | IEEE Transactions on Power Electronics |
Volume | 37 |
Issue number | 8 |
Pages (from-to) | 9073-9088 |
Number of pages | 16 |
ISSN | 0885-8993 |
DOIs | |
Publication status | Published - 1 Aug 2022 |
Bibliographical note
Publisher Copyright:IEEE
Keywords
- Bandwidth
- Couplings
- decoupling
- Grid-forming converter
- Power system dynamics
- Power system stability
- Reactive power
- Resistance
- small-signal stability
- Steady-state
- stiff grid