Various Droop Control Strategies in Microgrids

Droop control is a well-known strategy to control active power in power systems without internal communication. It is usually implemented on the conventional power plants to control the injected power of synchronous generators to the grid. As this strategy is local, there is no need to communication systems. Thus, it reduces the complexity and cost of the system operation and improves the reliability indices. Also, droop control has been used to control the active and reactive power of distributed generations in microgrids. Frequency and voltage control of microgrid and proper power sharing between DGs are the most important goals of droop control in the islanded mode of operation. The conventional droop control has some disadvantages that limits their application in the modern microgrids. Slow transient dynamics, load dependency of voltage and frequency, low accuracy on power sharing, low power quality for non-linear or unbalanced loads and circulating current between DGs are some of the main disadvantageous. Different methods have been proposed by researchers to overcome the problems, which are still an attractive subject for them. This chapter discusses different improved droop controllers, which have been used to overcome some of the problems.