Modelling of a New Configuration for DFIGs Using T-type Converters and a Predictive Control Strategy in Wind Energy Conversion Systems

Abstract

In this paper, a new topology is introduced for Doubly-Fed Induction Generators (DFIGs), applied in wind energy conversion systems. In the proposed topology T-type converters are used in back-to-back form instead of conventional converters. T-type converters are high-efficient three-level converters with high power quality. Furthermore, a hysteresis-based predictive control method is suggested for rotor current control of DFIG. Therefore, discrete models of the DFIG and T-type converters are extracted. A new equation is also defined for rotor current reference calculation which determines predictive current error. The suggested equation can be applied either for pre-connection to grid for synchronizing the DFIG or after connection to grid for regular control of DFIG. In addition to simulation results, the proposed topology is verified using a laboratory setup. The constructed setup is based on a 16-bit DSPIC and a wound-rotor induction machine. Simulation and practical results confirm effective operation of the proposed topology.