A Simple Flexible and Robust Control Strategy for Wind Energy Conversion Systems Connected to a Utility Grid

Figure 9

Performances of the grid side PI controllers in grid connected mode. (a) d-axis grid current reference (i), d-axis grid current component (ii), and d-axis grid current error (iii). (b) q-axis reference current (i), q-axis grid current component (ii), and q-axis grid current error (iii).

(a)

(b)