Robust Model Predictive Control for Onboard Interleaved Multilevel Boost DC-DC Converter in DC Shipboard Microgrids

DC shipboard microgrids (SMGs) are a low-carbon and feasible solution to host various distributed energy resources (DERs) and shipboard loads. However, the intermittency of DERs and constant power load (CPL) characteristic of the shipboard loads will compromise the stability of DC SMGs. To accommodate DERs and address the stability issue in space-stringent DC SMGs simultaneously, a compound large-signal stabilization scheme is proposed in this paper to operate the interleaved multilevel boost DC-DC converter (IMBDC) in DC SMGs. It combines the high-order nonlinear disturbance observer (NDO) technique and the offset-free model predictive control (MPC) algorithm. Specifically, the uncertain variations of CPLs and circuit parameters are modeled as disturbances. High-order NDOs are used to estimate these disturbances accurately within a finite time. Depending on the estimation and system model, the MPC will regulate the system states against large-signal disturbances. Simulation results demonstrate that the proposed algorithm outperforms the traditional linear and nonlinear control schemes with better stability and dynamic performances. Both the real-time simulation and hardware experiment results are provided to further validate the applicability and effectiveness of the proposed control strategy.