Design of a robust integral sliding mode controller considering continuous function-based fast power reaching law for DC microgrids

In this work, to maintain proper power in DC microgrids, a robust integral-sliding mode controller is designed by considering the continuous function-based fast power reaching law. In a DC microgrid to ensure the power balance, a constant and stable DC-bus is considered as a key indicator. Hence, controlling the DC microgrid's different components' output power is necessary to keep the DC bus voltage constant. To meet this control requirement, each microgrid component is interfaced to the DC-bus with a respective power electronic converter. The proposed DC microgrid compromises with a solar photovoltaic (SPV) system, a battery, and DC loads. Hence, the SPV is interfaced with a DC-DC boost converter to match its output voltage with the DC-bus voltage. On the other hand, a DC-DC buck-boost converter is used with the battery for controlling its discharging and charging current. The controller is designed for all of these components i.e., SPV and battery to control their corresponding output power while keeping a constant value of the DC-bus voltage. Afterward, to prove the overall stability of the system, the Lyapunov theory is used. Finally, a simulation study under different operating scenarios is conducted to validate the usefulness of the designed controller and it compares with the existing controller to confirm its superiority.