Low-voltage ride-through enhancement with the ω and T controls of PMSG in a grid-integrated wind generation system

This study deals with the formulation of a simple control strategy for the enhancement of the low-voltage ride-through (LVRT) capability of the grid-integrated permanent magnet synchronous generator (PMSG)-based wind generation system (WGS). The control warrants satisfying minimum required reactive current support to the ac grid as first priority with minimum loss of generation and maximum utilisation of the converter current capacity during LVRT compliance as per E.ON Netz German grid code requirements. The reference control variables in coordinated control of the stator-side and grid-side converters are altered so as to support the reactive current to the ac grid and, to store the excess active power in the system inertia for keeping the dc-link capacitor voltage in the safe limit during voltage dips at the grid side. The investigations have been made on the proposed strategy of LVRT enhancement with the speed (ω) and torque (T) controls of the direct-drive PMSG in grid-integrated WGS exploiting commonly used tip-speed-ratio and optimum-torque control algorithms of peak power tracking, respectively. Simulation results have been presented to validate the proposed strategy. The performances of the proposed strategy of LVRT enhancement has also been compared to the conventional method like dc-link braking chopper.