Improved Parameter Identification and Control Strategy of Pitch Motor in Wind Turbine System

Abstract

Variable load and rotor time constant Tr in pitch motor may lead to low robustness of pitch control system. Therefore, an improved Tr identification method and control strategy were presented. Firstly, based on flux estimator in pitch control system, the influences of motor parameters on flux were analyzed using Frequency Response Functions (FRF), which could derive the dominant parameter. Secondly, based on the Model Reference Adaptive System (MRAS), the initial value of identification was treated as the compensation term to weaken the effect of variable motor speeds and load torques, then the pitch control strategy with this improved MRAS-based identification for Tr in wind turbine system were developed. Finally, simulation and prototype test of pitch motor control system were carried out. The results have validated that Tr has a prominent impact on the pitch control system, the improved identification model and control strategy considering online identification would be more robust.