Performance Analysis of DC Microgrid Considering Ramp Rate Limiter

Virtual inertia (VI) is considered to be an effective method to reduce the rate of change of voltage (RoCo V). Compared with VI, the ramp rate limiter (RRL) could accurately control RoCo V when a disturbance occurs in a DC microgrid (MG), but its impact on the system stability remains unclear when constant power loads (CPL) are included. In this work, the RRL, as a complement to VI, is used to accurately control RoCo V. By modeling the system with RRL, it is demonstrated that RRL would reshape the primary control loop of the DC MG, and decrease the order of the system model. Small-signal and large-signal stability of the system containing RRL and CPL are analyzed. It is demonstrated that RRL could enhance the stability of the DC MG. Furthermore, it is proved that the rate of RRL would not affect the steady-state performance of the DC MG. The proposed method is compared with VI to demonstrate the feasibility and performance of the proposed method using simulation results.