Analysis of ADRC with Complex Pole and Design of ESO Based SMC

Nowadays, challenges in load frequency control (LFC) are increasing to consider various non-linearity in the system. To deal with disturbance in the LFC system active disturbance rejection control (ADRC) is a popular approach. Linear ADRC fails successfully to deal with non-linearity in the system. A robust control technique using sliding mode controller (SMC) which effectively deal with uncertainty of the system is proposed. In this paper, an SMC with full order extended state observer (ESO) is designed. The controller and observer gains are obtained using pole placement technique and is used to design the SMC. The observer-based SMC is investigated for single area non-reheat system without and with non-linearity like generation rate constraint (GRC) and governor dead band (GDB). The parameter of the non-linear ESO i.e., <tex xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">$\alpha= 0.1, \delta= 0. 1$</tex> gives the best response for non-reheat LFC system whereas <tex xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">$\alpha=0.5$</tex> and <tex xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">$\delta=0.1$</tex> gives the best response for the reheat system.