A three-phase programmable voltage sag generator for low voltage ride-through capability test of wind turbines

As the wind power penetration is increasing rapidly into the power grid, modern gird codes require the wind turbines (WTs) to possess the low voltage ride-through (LVRT) capability. In order to evaluate the performance of a WT under grid fault conditions, a voltage sag generator (VSG) is needed to simulate all kinds of grid faults. This paper investigates a three-phase programmable VSG based on a voltage source inverter (VSI). A novel dual-loop proportional integral resonant (PIR) controller with a zero sequence voltage compensation scheme is applied to control the VSI, so that the four kinds of possible grid voltage dips can be precisely simulated. The effectiveness of the proposed VSC is validated by the experimental results.