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

Figure 11

Performances of the grid side PI controllers in automatic switching mode. (a) d-axis grid current (i), q-axis grid current (ii), d-axis grid current error (iii), and q-axis grid current error (iv). (b) Inverter phase current (i), load phase voltage (ii), grid phase current (iii), and inverter control signal (iv).

(a)

(b)