Reverse droop control strategy with virtual resistance for low-voltage microgrid with multiple distributed generation sources

Abstract

In the island operation mode of the microgrid, the rated capacity and feeder impedance of each parallel distributed generation inverter are different and the output power is difficult to be reasonably distributed when the traditional droop control strategy is adopted, which reduces the stability of the system. In order to solve this problem, the power transmission characteristics of low-voltage microgrid are analyzed and the leading factors affecting the reasonable power distribution are obtained. A control strategy of virtual resistor is proposed and the difference between the actual output power and the expected output power is used to control the power compensation coefficient and proportional integration to adjust the reference voltage of each DG inverter. The control strategy can automatically adjust the change in the output power of the distributed power supply in real time, adjust the voltage change caused by the line impedance mismatch in time, improve the power quality, reduce the system circulation, and realize the reasonable distribution of power. Finally, the simulation model verifies the effectiveness of the strategy.

Keywords

• droop control
• distributed generation inverter
• microgrid
• reverse droop control
• virtual resistor