Robust Power Oscillation Damping by DFIG Wind Turbine using Mixed H2/H∞ Control

The robust power oscillation damper (POD) design for doubly fed inducting generator (DFIG) based on a mixed H2/H∞ control method is proposed in this paper. A practical 2-order lead/lag compensator with local input signal is chosen as the POD structure. The POD is additionally installed with the voltage control loop of DFIG so that the modulation of reactive power output can be performed to damp out power oscillations. To acquire both damping performance and robustness, the optimization of POD parameters is formulated based on a mixed H2/H∞ control. The backtracking search algorithm is automatically employed to solve the optimization problem. Simulation study indicates that the damping effect and robustness of the proposed robust POD are higher than those of the conventional POD against various system faults, heavy power flow levels, and wind patterns.