DC Bus Voltage Sliding-mode Control for a DC Microgrid Based on Linearized Feedback

When constant power load with negative impedance characteristics and distributed power sources are integrated into a DC microgrid via converters, oscillation may easily occur, causing the system stability problem. Based on the linearization feedback theory, a sliding mode controller used for the DC bus voltage control system of the bidirectional DC-DC converter was investigated to quickly track power disturbances in the DC microgrid, which has good robustness to system parameter change and external disturbance. The simulation model of DC microgrid with 1kw and 5kw external constant power load is built with MATLAB/Simulink and the simulative results show that, the stability of DC microgrid can be guaranteed by the proposed control strategy under both island and grid-connection operations.