Abstract
The modular multilevel converter (MMC) has attracted significant interest for medium-/high-power energy conversion applications due to its modularity, scalability, and excellent harmonic performance. One of the technical challenges associated with the operation of the MMC is the circulation of double-frequency harmonic currents within its phase legs. This paper proposes a circulating current control strategy in a double-frequency rotating reference frame, which, contrary to the existing solutions that are based on approximate/inaccurate models, relies on an experimentally identified nonparametric model of circulating currents to determine the coefficients of the controller. Minimizing the squared second norm of the error between the open-loop transfer function of the system and a desired one, the coefficients of the controller are determined. To guarantee the stability of the closed-loop system, the minimization problem is subjected to a few constraints. The validity and effectiveness of the proposed control strategy is confirmed, and its dynamic performance is compared with that of an existing solution by experimental results.
| Original language | English |
|---|---|
| Article number | 7046433 |
| Pages (from-to) | 783-792 |
| Number of pages | 10 |
| Journal | IEEE Transactions on Power Electronics |
| Volume | 31 |
| Issue number | 1 |
| DOIs | |
| State | Published - Jan 1 2016 |
| Externally published | Yes |
Keywords
- Circulating current
- convex optimization
- current control
- double-frequency reference frame
- loop shaping
- modular multilevel converter (MMC)