Combined Sliding-Mode Control for the IFDBC Interfaced DC Microgrids With Power Electronic Loads

The interleaved floating dual boost converter (IFDBC) is well known for its high voltage gain and low current and voltage ripples. Besides, thanks to its interleaved structure, this topology is quite suitable for high-power applications, such as the solar photovoltaic or energy storage systems that are employed to feed or buffer the dc microgrid (MG). In modern MGs, tightly regulated power electronic loads, which behave like constant power loads (CPLs), are penetrating. Such loads exhibit negative incremental impedance and thus, threaten the dc bus voltage stability in MGs. To stabilize the dc bus voltage of IFDBC-fed MG in the presence of rapid and large load disturbances, this article proposes a new nonlinear disturbance observer (NDO) based sliding-mode control. The proposed method guarantees global stability of dc bus voltage regulation and provides fast dynamic responses. In addition, to simplify the design of the proposed approach, a generalized reduced order model of IFDBC is developed. Simulation and experiment results are presented to verify the effectiveness of the proposed control approach.