Control Strategy for DFIG-based Variable Speed Pumped Storage Power Plants Under Balanced and Unbalanced Grid Conditions

Abstract

This paper proposes a vector control (VC) strategy for doubly fed induction generator (DFIG) in variable speed pumped storage power plants (PSPPs), which work in balanced and unbalanced grid conditions. The grid voltage oriented VC strategy with PI controller employed to DFIG operating in generation and electrical mode. Aiming to eliminate current oscillations under unbalanced grid conditions, the positive-negative sequences decomposition control strategy is employed to realize the low-voltage ride-through (LVRT) capability. Mathematical models of DFIG-based PSPPs are analyzed, and simulations are implemented in MATLAB to verify the theoretical findings, which show the effectiveness of the proposed control strategy.