Novel Nonlinear Time Domain Optimal Control Formulation of Wind Turbine Power System with GPOPS2 Software Simulations

Formulating a wind turbine power system (WTPS) as an optimal control problem is very natural and with great appeal – given the optimized objectives WTPSs always aim at achieving, such as but not limited to maximizing power generation and reducing fluctuations in the generated power; these objectives are better to be achieved especially when the WTPS is experiencing sudden changes or even faults. However, the literature does not provide much contributions in this domain given the nonlinearity of the problem and the lack of highly accurate time domain models. In this paper, we provide a novel nonlinear optimal control formulation for WTPSs taking advantage of very recent developments in accurate nonlinear time-domain modeling of WTPSs. This novel formulation enable, for the first time in the literature of WTPSs, the use of powerful optimal control solvers which traditionally work with systems of differential equations. We use in this paper the software optimal control solver GPOPS2, which is compatible with available software such as MATLAB
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; this powerful solver has been proven promising in other fields such as unmanned aerial systems and robotics. we provide some simulation cases which show that optimal control solutions outperform PID controllers traditionally used by industry. We follow that with discussion on this novel approach and intended future directions.