A linear quadratic regulator for small signal stability improvement of grid connected PMSG

The PMSG wind turbine with grid connectivity has been getting attention as it has the low maintenance requirements and also greater power extraction. Since the rating of PMSG available till now is of medium power ratings it is mostly integrated into medium voltage level in the transmission system. The reactance at this voltage level is different compare to the high voltage transmission system. This paper presents the analysis of PMSG based wind turbine when connected to weak grid scenario. Also, an LQR based control is proposed for making the system stable in varying grid strength. A mathematical model of the grid-connected PMSG system is presented. A differential algebraic based linearization for eigen value analysis is also presented to give the clear distinction of system stability. An ODE-based coding has been carried out in MATLAB to carried out the proposed control verification.