Fuzzy logic improved washout filter-based method for voltage restoration in DC microgrids

This paper proposes an improved method for voltage restoration in DC microgrid without using communication lines. Due to nature of traditional droop control, the voltage of the microgrid droops a small amount to achieve load sharing. However, in some situations the load requires high quality power supply and the voltage deviation is unacceptable. This can be solved by using a secondary control to generate a correction signal based on real-time measurement. However, this control structure requires a low bandwidth communication links; therefore the most significant advantage of the droop method is compromised. A washout filter-based control method has been recently proposed to solve the drooping without communication lines, however it suffers from the tradeoff between system stability and restoration speed. A fuzzy logic based compensator proposed in this paper improves the transient response of the washout filter based method without affecting the power sharing and stability.