Improved Reactive Power Sharing Between Droop Controlled Inverters In Islanded Microgrid

Generally, a droop control is used for power sharing among distributed generators (DGs) in islanded microgrid. This paper investigates the problem of reactive power sharing among DGs when using droop strategy as primary control. The advantage of droop control is that it allows inverters to mimic the droop characteristics of synchronous generator in grid connected or in islanded mode. It has been observed that such control strategy results in proper sharing of real power but reactive power sharing among DGs deteriorates. A modified droop strategy is proposed here that improves the reactive power sharing between distributed generators (DGs) without any secondary controller. Advantage of this droop strategy is that it only uses local measurements. However, because of the line impedance between DGs reactive power cannot be shared equally. It was also shown that because of coupling between real and reactive power, this strategy also improves the voltage and frequency deviations in case of load changes.