Fuzzy Logic Enhanced Q–dV/dt Droop Control for Accurate Reactive Power Sharing in Islanded Microgrids

Resumo

Rapid growth in energy demand has made it necessary to come up with solutions for alternate sources of energy. Microgrids with parallel connected inverters for decentralized  power integration are emerging as a great solution. Reactive power sharing encounters a lot of challenges in parallel connected inverters especially during islanded operation of microgrid. Conventional Q-V droop control faces issues like improper reactive power sharing and deviation of frequency specifically during the conditions of unequal line impedance. This paper does an comparative study of reactive power sharing among two parallel connected inverters in islanded microgrid environment using three different droop control strategies like conventional P-f Q-V droop control, P-f Q-dV/dt and fuzzy logic based P-f Q-dV/dt with help of simulations in MATLAB Simulink platform. Simulation results show that reactive power  sharing values in case of P-f Q-V droop control deviates  from its nominal value by 17%, which is reduces to 3.33% in case of P-f Q-dV/dt and is almost 2% for fuzzy logic based P-f Q-dV/dt. The frequency varies from 50.55 to 51.5 in case of P-f Q-V droop control, 49.2 – 50.01Hz for P-f Q-dV/dt and 49.5 – 50.01Hz for fuzzy logic based P-f Q-dV/dt control technique, showcasing better frequency regulation.