Toward Large-Signal Stabilization of Floating Dual Boost Converter-Powered DC Microgrids Feeding Constant Power Loads

In modern dc microgrids (MGs), floating dual boost converters (FDBCs) take the advantages of both interleaved modulations and higher voltage gains, and the FDBC topology has been shown rather suitable for high-power applications. For a given dc MG, those power electronic loads and motor drives would behave as constant power loads (CPLs) that have negative incremental input impedances causing serious stability issues. To make the FDBC-enabled dc MG more adaptable to the increasing penetration of CPLs, this article proposes a compound stabilizer that is capable to stabilize all states in the converter in the large-signal sense. The stabilizer is synthesized by nonlinear disturbance observers and a recursive backstepping controller. The observers provide disturbance estimations to the controller, which neutralizes the disturbances in a feedforward manner and also guarantees the large-signal stabilization of MG under Lyapunov theorems. Practical parameter identification procedures are provided, and it is shown that the proposed stabilizer contributes the wider stability margin to the FDBC than the commonly used proportional-integral (PI) control. Finally, hardware experimentations substantiate the effectiveness and feasibility of the large-signal stabilizer.