| Title |
Droop Method for High-Capacity Parallel Inverters in Islanded Mode Using Virtual Inductor |
| Authors |
Kyo-Sun Jung ; Kyung-Bae Lim ; Dong-Hwan Kim ; Jaeho Choi |
| DOI |
10.6113/TKPE/2015.20.1.81 |
| Keywords |
Parallel inverter; Droop control method; Virtual inductor; Islanded mode; Power sharing; DG(Distributed Generation) |
| Abstract |
This paper investigates the droop control-based real and reactive power load sharing with a virtual inductor when the line impedance between inverter and Point of Common Coupling (PCC) is partly and unequally resistive in high-capacity systems. In this paper, the virtual inductor method is applied to parallel inverter systems with resistive and inductive line impedance. Reactive power sharing error has been improved by applying droop control after considering each line impedance voltage drop. However, in high capacity parallel systems with large output current, the reference output voltage, which is the output of droop controller, becomes lower than the rated value because of the high voltage drop from virtual inductance. Hence, line impedance voltage drop has been added to the droop equation so that parallel inverters operate within the range of rated output voltage. Additionally, the virtual inductor value has been selected via small signal modeling to analyze stability in transient conditions. Finally, the proposed droop method has been verified by MATLAB and PSIM simulation. |