A Health-Oriented Power Control Strategy of Direct Drive Wind Turbine

Offshore wind power has great development potential, of which operation and maintenance costs account for a large proportion in the full lifecycle cost. Power output control strategy plays a key role in wind turbine generator system (WTGS). Traditional control strategies, such as maximum power point tracking and unity power factor, which only uses current local information for decision-making, are not the optimal control method when considering the component fatigue. For the reason, this paper proposes a health-oriented power control strategy, which transforms control problem into an equivalent solution to an economic revenue model. The model aimed to maximize the economic revenue of the full lifecycle, and employed physics-of-failure methodology to quantify the remaining useful life, involving detailed mission profiles. Further, a receding horizon predictive controller is designed to flatten the junction temperature fluctuation and extend converter lifespan, for engineering application. A 1.2 MW WTGS is utilized as a benchmark to verify the proposed strategy performance, and the numerical results reveal the mechanism of the optimized control strategies for alleviating the fatigue and aging of the converters.