Primary frequency control of a microgrid with integrated dynamic sectional droop and fuzzy based pitch angle control

Abstract

In a microgrid (MG), employing conventional fixed droop gain control of wind turbine for mimicking conventional generators may threaten grid stability. In this paper, an integrated control strategy of inertia emulation and dynamic sectional droop control for generating active power reference of the wind power system is presented to provide primary frequency control (PFC) services. The dynamic sectional droop is implemented with the fuzzy logic controller (FLC) regulated pitch angle control mechanism and compared with the conventional proportional-integral (PI) pitch angle control method in the isolated MG. Two different gain values are selected for developing the proposed sectional droop control which is based on the sensitivity of frequency deviation in comparison to the single fixed gain in conventional droop control. The maximum power margin of wind turbine is considered as 25% and 15% for a wind speed higher than (or equal to) the rated speed and lower than the rated speed, respectively. The effectiveness of the proposed method is investigated through Matlab/Simulink based real-time simulation studies. Simulation results demonstrate that the proposed sectional droop control provides superior performance than conventional fixed-gain method and achieves optimum frequency regulation at the rated wind speed and even for a wind speed lower than the rated wind speed.