Analysis of Operation Modes and Grid-Connected Control for the Dual-Stator Brushless Doubly Fed Induction Generator

This paper presents a dual-stator brushless doubly fed induction generator (DS-BDFIG), with emphasis on the analysis of operating modes and the grid-connected control. The DS-BDFIG can perform under serval operation modes, including the general asynchronous operation, the cascaded asynchronous operation and the doubly fed synchronous operation. A deeper investigation of the asynchronous mode is carried out since the DS-BDFIG provides the capacity of behaving as a conventional induction machine which can play a big role when the DS-BDFIG starts or the converter fails. For achieving the grid-connected mode, an inner CW current-loop and an outer power-loop are designed to achieve a grid-connected DS-BDFIG system controller. Experimental assessment based on the DS-BDFIG grid-connected generation system is carried out to verify the effectiveness of the theoretical analysis.