PWM converter control for grid integration of wind turbines with enhanced power quality

Variable-speed wind turbines are attractive to the high performance and are widely used by the wind turbine industry today. A variable-speed wind turbine has a back-to-back PWM converter consisting of a machine-side converter for generator control and a grid-side converter for grid interface. Traditionally, the grid-side converter is controlled through decoupled d-q vector control mechanisms through a voltage regulated PWM converter. This paper develops a steady-state model of the grid-side converter system in a d-q reference frame, based on which general power control characteristics of the grid-side converter are studied both analytically and through computer simulation. Drawbacks of the conventional control strategies are analyzed. A novel control technique is developed for the consideration of both effective real and reactive power control and improved power quality. The controller performance is evaluated through a transient simulation approach using MatLab SimPowerSystems, which demonstrates that the newly developed control mechanism is effective for grid interface of the converter in terms of superior power control and enhanced power quality.