On-line Estimation of the Parameters of the Windmill Power Coefficient

TL;DR

This paper introduces a globally convergent online estimator for wind turbine power coefficient parameters, enabling optimal operation without invasive disturbances or unreliable manufacturer data.

Contribution

It presents the first solution to the nonlinear, nonlinearly parameterized, underexcited system identification problem for wind turbine power coefficients.

Findings

Estimator converges exponentially in real-time

Applicable without harmonic disturbances or reliable manufacturer data

Addresses a practically important nonlinear identification challenge

Abstract

Wind turbines are often controlled to harvest the maximum power from the wind, which corresponds to the operation at the top of the bell-shaped power coefficient graph. Such a mode of operation may be achieved implementing an extremum seeking data-based strategy, which is an invasive technique that requires the injection of harmonic disturbances. Another approach is based on the knowledge of the analytic expression of the power coefficient function, an information usually unreliably provided by the turbine manufacturer. In this paper we propose a globally, exponentially convergent on-line estimator of the parameters entering into the windmill power coefficient function. This corresponds to the solution of an identification problem for a nonlinear, nonlinearly parameterized, underexcited system. To the best of our knowledge we have provided the first solution to this challenging, practically important, problem.