Mathematical modeling and stability analysis of DC microgrid using SM hysteresis controller

The use of dc microgrids in the residential and commercial complexes are increasing due to the high reliability, high efficacy, and easy integration with renewable energy sources. This paper presents the voltage stability of dc microgrid based on decentralized control architecture. Droop controllers cascaded with proportional integral (PI) controllers are being used for stability of dc microgrid. Droop control is not effective due to the error in steady state voltages and load power variations. Additionally, PI controllers cannot ensure global stability. It exhibits slower transient response and control parameters cannot be optimized with load power variations. To address the aforementioned limitation, sliding mode hysteresis control is proposed in this paper. Main advantages are high robustness, fast dynamic response and good stability for large load variations. To analyze the stability and dynamic performance of the proposed scheme, a system model is derived and its controllability, observability and stability are verified. Modeled dynamics are graphically plotted and presented. Detailed simulations are carried out to show the effectiveness of SM controller and results are compared with droop controller. The transient behavior on step load is also investigated and presented which shows the good performance of the proposed controller. A scaled down experimental setup of a source is also presented in the Appendix A.