Combined input-output linearisation and internal model control for parabolic trough solar plant

The parabolic trough solar plant (PTSP) is a widely used technology for alternative energy sources. The dynamic behaviour of this system is described by hyperbolic partial differential equations (PDEs), which makes control design a challenging problem. The use of a reduced or an approximate model leads to limited performance. Thus, to enhance the efficiency of the PTSP, sophisticated control strategies that rely on the PDE model are needed. In this paper, a control strategy that combines input-output linearisation and internal model control is proposed. Input-output linearisation is adopted to design a state feedback that yields a finite-dimensional closed loop system. To ensure robustness against disturbances and physical parameter uncertainties (such as specific heat capacity and density), an internal model controller is used to generate the external input for the linearising state feedback. Assuming actual daily profiles of solar radiation, the performance of the control scheme is evaluated through numerical simulations. The tracking capabilities of the proposed control scheme are demonstrated via simulation.