Design of robust converter interface for wind power applications

As the amount of wind power and other distributed generation with power electronic interface in the grid grows, it becomes unacceptable to disconnect generating units every time a disturbance occurs, as was common practice in the post. Keeping the voltage source converter on-line during unbalanced voltage dips thus becomes a very critical issue. In this article the design of a robust converter interface for wind turbines is investigated. Based on the classification of unbalanced faults that can occur in the grid, resulting in voltage dips at the bus where the turbine is connected, the maximum current that the converter valves must be able to withstand is calculated The effect of phase angle jumps during faults is also investigated. It is demonstrated that, ultimately, the converter design con be optimized by using statistics of voltage dips and the wind speed distribution for the specific site considered. This is shown by a design example. Copyright (c) 2005 John Wiley & Sons, Ltd.