New control strategy with CB-P for improved FRT capability of grid-integrated DFIG based wind energy system

Abstract

A new control prospective is adopted in this paper to enhance the Fault Ride Through (FRT) capability of the variable speed Induction Generator along with a Crowbar protection circuit. The Induction Generator is a Doubly Fed Induction Generator (DFIG) used in a Wind Power Conversion System (WPCS). The DFIGs interconnected with the grid are very much sensitive to any disturbance in the grid. The stator of the generator is directly connected to the grid. Hence occurrence of any fault near the grid, immediately leads to a sag in the stator voltage of the generator causing overcurrents as well as overvoltages in the rotor windings. As a result there is a chance of damage of the partial fraction Rotor Side Converter (RSC) during fault. In order to protect the converter, here in this paper a new crowbar protection design is adopted along with the proposed control technique. The proposed strategy is validated through simulation results. The Simulations are carried out in MATLAB on a 1.7 MVA DFIG system and the effectiveness of the new protection design is verified.