T-type based Grid-Side Converter Control Design of Double Fed Induction Generator – A practical approach

Abstract

In this paper, the control design for the grid-connected converter used as a part of the wind turbine generator is discussed. First, the three-phase T-type multilevel converter, which exhibits several advantages such as low total harmonic distortion, reduced voltage stress, and switching loss, is employed for the power stage. Second, finite control set model predictive control (FCS-MPC) is adopted to achieve a multi-objective optimization solution for the inner grid-connected current control loop. This approach not only allows the current to quickly track its desired value but also minimizes the capacitor voltage balance and the switching loss. Finally, a practical approach is proposed to design the Fuzzy-based PI controller for the DC bus voltage regulation. The design procedure is straightforward, and only requires several known information getting from the converter. Specifically, the proposed controller allows users to exactly restrict the inrush current, as well as minimize the overshoot of the DC bus voltage during startup. The effectiveness of the proposed control strategy is verified by numerical simulations. In which all controlled algorithms are implemented by standard C language such that the consistency between simulations and future practical implementations is guaranteed.