Abstract
This paper proposes a method to monitor the impedance-based stability margin of grid-connected converters in real-time. A three-phase converter is configured to inject a broadband perturbation on top of its nominal output current to enable online identification of grid impedance. The ratio of converter and grid impedance is computed in real-time by utilizing the measured grid impedance and the analytical impedance model of the inverter. A Nyquist contour is plotted based on the impedance ratio. The contour can be used to assess impedance-based stability margin and to allow, e.g., adaptive tuning, more efficient post-fault diagnostics or to enable re-selection of control parameters. The method is implemented on a dSPACE real-time control platform and the associated Control Desk software. The paper also discusses potential limitations and suggests future improvements. A short video is available online to further illustrate the method.
| Original language | English |
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| Title of host publication | Proceedings of 2017 IEEE 18th Workshop on Control and Modeling for Power Electronics (COMPEL) |
| Number of pages | 8 |
| Publisher | IEEE Press |
| Publication date | Jul 2017 |
| ISBN (Electronic) | 978-1-5090-5326-1 |
| DOIs | |
| Publication status | Published - Jul 2017 |
| Event | 18th IEEE Workshop on Control and Modeling for Power Electronics, COMPEL 2017 - Stanford, United States Duration: 9 Jul 2017 → 12 Jul 2017 |
Conference
| Conference | 18th IEEE Workshop on Control and Modeling for Power Electronics, COMPEL 2017 |
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| Country/Territory | United States |
| City | Stanford |
| Period | 09/07/2017 → 12/07/2017 |
Keywords
- Impedance-based stability analysis
- Online grid impedance measurement
- Pseudo-random binary sequences
- Grid-connected three-phase inverter