A Nonlinear Inductor-Based MPC Technique for DC Cascaded System Including Constant Power Loads

This paper presents a nonlinear inductor (NI) based model predictive control (MPC) technique for a DC/DC boost converter powering a constant power load (CPL) in a DC cascade system. The integration of the CPL introduces a negative incremental impedance (NII) characteristic at the output, which causes unwanted oscillations in the DC output voltage. This technique improves the stability of DC cascaded systems by employing NI and predictive models that reduce the predictive horizon and computational burden. This results in smoother inductor current, improved steady-state operation, and faster dynamic transition performance. Furthermore, the proposed technique simplifies system design and allows fixed switching frequency operation, making it more practical. In addition, an observer is deigned for obtaining the uncertain value of the CPL. Simulation and experimental results confirm that this technique effectively achieves stable operation and mitigates DC output voltage oscillations.