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Simulation parameters used in proposed configuration_
| S. no | Parameter | Value |
|---|---|---|
| 1 | Rated active power | 20 MW |
| 2 | Rated reactive power | 6.6 VAR |
| 3 | DC supply | 33 kV |
| 4 | DC link capacitor value | 300 µF |
| 5 | Converter output voltage RMS | 11 kV |
| 6 | Number of sub-modules per arm | 6 |
| 7 | Each sub-module capacitor value | 0.03 F |
| 8 | Each sub-module capacitor voltage | 5,500 V |
| 9 | Resistance of arm | 0.01 Ω |
| 10 | Inductance of arm | 5 mH |
| 11 | Line frequency | 50 Hz |
| 12 | Carrier switching frequency | 2 kHz |
Literature review_
| Reference | Focus area | Key contribution | Limitations |
|---|---|---|---|
| Marquardt (2001) | MMC fundamentals | Introduced MMC topology for scalable high-voltage applications | Early work lacked detailed control strategies for circulating currents |
| Rodriguez et al. (2009) | Multilevel converters | Overview of multilevel converter topologies and their industrial applications | Limited focus on MMC -specific challenges like capacitor balancing |
| Dekka et al. (2017) | MMC evolution | Comprehensive review of MMC topologies, modulation and control methods | Did not address advanced harmonic suppression techniques |
| Tu et al. (2011) | Circulating current control | Proposed PI controllers in double-fundamental rotating frame for harmonic reduction | Ineffective under unbalanced grid conditions |
| Li et al. (2013) | Passive control method | Introduced arm inductance/resistance for circulating current suppression | High voltage disturbances and instability risks |
| Zhang et al. (2014) | Hybrid control | Combined PI and repetitive controllers for harmonic elimination | Complex tuning, limited transient performance |
| He et al. (2015) | Series PI-repetitive control | Enhanced PI transient performance with repetitive steady-state control | Restricted bandwidth, unsuitable for non-integer harmonics |
| Bergna et al. (2013) | Energy-based control | Decoupled double synchronous frame for sequence component regulation | High computational complexity, limited to three-phase systems |
| Proposed method | EOGI-based control | Parallel multi-harmonic EOGIs (2nd, 4th and 6th-order) | Requires ISE-optimised gains but achieves stability via Popov criterion |