Abstract
The 2 N +1 submodule unified pulsewidth modulation (SUPWM) is attractive for modular multilevel converters (MMCs). To generate 2 N +1 voltage levels, the SUPWM results in voltage pulses imposed on the arm inductors, which produces large high-frequency current ripple in the dc link of the MMC and deteriorates the dc-link performance. In this article, the dc-link high-frequency current ripple under 2 N +1 SUPWM is analyzed and a reduced dc-link current ripple control method is proposed for advanced 2 N +1 SUPWM. By regulating the phase angles of the three-phase carriers in each carrier period, the resulted voltage pulses on the arm inductors of three phases can be counteracted, and therefore the dc-link high-frequency current ripple is suppressed. With the proposed method, the MMC has much reduced dc-link current ripple, which effectively improves the performance of the MMC under 2 N +1 SUPWM. Simulations and experiments are conducted to verify the validity and effectiveness of the proposed control.
| Original language | English |
|---|---|
| Article number | 9600570 |
| Journal | I E E E Transactions on Power Electronics |
| Volume | 37 |
| Issue number | 4 |
| Pages (from-to) | 4261-4274 |
| Number of pages | 14 |
| ISSN | 0885-8993 |
| DOIs | |
| Publication status | Published - Apr 2022 |
Keywords
- 2N+1 submodule (SM) unified pulsewidth modulation (SUPWM)
- control strategy
- dc-link current ripple
- modular multilevel converters (MMCs)