Quantifying the Impact of Drivetrain Flexibility on PID-Based MPPT Performance in Modern Wind Turbines: A Simulation-Based Comparative Study

Abstract

The following is a detailed account of how the flexibility of a drive train affects maximum power point tracking (MPPT) for wind turbines. The study uses the National Renewable Energy Laboratory 5 MW reference turbine as a base model with Kaimal spectrum having felt waves creating turbulent winds. This study compares both rigid and flexible drive trains that undergo identical turbulence conditions (average wind speed 9.0 m/s and flight weather turbulence, 16% T.I.). The results show that the flexible unit provides an 8.95 percent area increase in mean power coefficient, (p < 0.001, Cohen’s d = 2.108) while the rigid unit produces a 4173 percent (p < 10−47, Cohen’s d = 31.8) sudden rise in power during catastrophic loss of control and produce a direct torque oscillation of over 153 MN·m RMS between the two configurations. The conclusion of this research establishes that PID Controllers that are manually tuned based on measurements taken with rigid drive trains cannot be used with flexible drivetrains. Therefore, it is necessary to either re-tune the PID Controller quickly after switching between form of drive train; and/or implement advanced control strategies to effectively manage these situations in the future. This study shows that rigid-model assumptions are fundamentally inadequate for contemporary turbine control design, which directly results in decreased energy yield. The findings necessitate a paradigm shift towards control strategies that specifically take structural dynamics into consideration in order to produce vibration-resilient MPPT for next-generation turbines.