Active Power Control of Wind Turbine Generators Considering Equilibrium Point Optimization Under Passive Rotor Speed Variation Mode

With the deepening penetration of wind generation in power systems, it is urgent that wind turbine generators (WTG) can have active power control (APC) capabilities, i.e., WTG can adjust active power output according to the power command from wind farms. The improvement of APC performance is closely related to the rotor speed variation (RSV) mode and the optimal setting of stable equilibrium points (SEP). Compared with the active RSV with the same SEP, the passive RSV no longer focuses on the rotor speed tracking and has lower power response discrepancy and drive-train loads. However, limited by the realization principle, APC based on passive RSV overlooks the optimization and setting of SEP, which makes the rotor speed of WTG easily reach the bound of the variable-speed range and leads to speed overshoot and power drops. Hence, this paper proposes an APC method with additional pitch angle compensation. Consequently, WTG under passive RSV has the ability of optimizing and setting SEP. On this basis, the compensation pitch angle is dynamically optimized according to the predicted wind speed. The experimental results show that the proposed strategy can effectively reduce speed overshoot and power drops while taking full advantages of passive RSV.