Adaptive Droop Coefficient of DC Distribution System Based on Voltage Oscillation Characteristic

Abstract

DC distribution system has become an important direction in improving the stability and reliability of the power system. Based on the research of the oscillation mechanism and frequency characteristics of DC voltage, a control method with variable droop coefficient is proposed to solve the voltage oscillation problem under droop control. The result of a differential operation on the voltage is used by the comparator and counter to compare with the threshold to judge whether the bus voltage oscillates or not. The oscillation frequency is calculated to change the droop coefficient adaptively based on the obtained analytical expression between the oscillation frequency and droop coefficient. The simulation model of the DC distribution system is built in Matlab/Simulink. The result verifies that the proposed method provides a new way in changing the droop coefficient adaptively to improve the voltage oscillation and enhance the system stability effectively.