Active Power Control of Wind Turbine Generators Based on the Maximum Disturbance Range of Nonpitch Regulation

Wind turbine generators (WTG) are expected to provide active power control (APC) to track active power instructions from the power grid or wind farm operators. Because the regulation of turbines' mechanical dynamics strongly depends on pitch angle regulation, mitigating frequent pitch adjustments is a key issue, and accordingly, several rotor speed variation-first APC methods have been proposed to decrease pitch servo fatigue. However, due to the lack of a quantitative description on the utilization of rotor speed variation (RSV), the ability of reducing pitch action through RSV can hardly be analyzed and compared among the existing APC methods. Hence, the disturbance range of nonpitch regulation (DRNP) and the maximum DRNP are defined in this paper. The former represents the effect of pitch action mitigation through RSV with a specific APC strategy and provides a unified foundation for quantitatively evaluating and selecting APC methods from the perspective of pitch servo serviceability. The latter, which depends on the turbine specifications and is independent of the control method, represents the maximum effect that can be achieved for a WTG. On this basis, an improved APC method is proposed to further reduce pitch servo fatigue. Finally, the DRNP indicators and the effectiveness and feasibility of the proposed method are verified by the wind turbine simulator-based experiments.