Modified Droop Control for Support System Voltage with PID and its Implementation to Multi-VSCs for GFM Inverter

After reviewing recent studies on basic droop-control techniques, the authors proposed a modified droop-based control and obtained good results by applying it to a single VSC. This paper further investigates the extension of the proposed modified droop control with PID to multi-VSC. Simulation results show that the proposed method has a very good tracking effect on the command voltage
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, Simulation results using the MATLAB/Simulink tool with the Simscape library show that the proposed modified droop control can further improve the voltage support capability over the general droop control. The implementation results also indicate that the modified droop control applies to future GFMs which include multi-VSC.