Designing robust hybrid controllers for enhancing output voltage regulation in CPL feed boost converters through backstepping and nonsingular fast terminal sliding mode approaches

Abstract

This paper presents a novel and robust hybrid controller that combines the backstepping controller with the nonsingular fast terminal sliding mode controller (NFTSMC) for DC-DC boost converters (DDBCs) operating alongside constant power loads (CPLs). The primary aim of the controller is to enhance the stability of the DC-bus voltage while consistently delivering power to the CPL. To achieve this objective, the exact feedback linearization approach is applied to transform the nonlinear dynamical model of the DDBC into Brunovsky’s canonical forms. The incorporation of matched uncertainties into the dynamical model illustrates the robustness of the proposed control approach. The hybrid controller is formulated based on this model, leveraging Lyapunov stability theory to ensure large signal stability under the designated control law. Significantly, the NFTSMC effectively addresses the singularity problem associated with sliding mode controllers (SMCs). The effectiveness and resilience of the proposed controller are validated under variations in input voltage, reference voltage, and power demand. Comparative analysis is conducted by contrasting simulation results with those obtained using conventional SMC (CSMC) and a typical PI controller (PIC). The results unequivocally highlight the superiority of the proposed controller in terms of ensuring system stability and providing a rapid response across various operating modes. Furthermore, to authenticate the practical applicability of the proposed controller, processor-in-loop (PIL) validation is employed, confirming its effectiveness in real-world scenarios.

Keywords

• Constant power load
• DC microgrid
• Lyapunov function
• PIL
• Robust hybrid controller