A Lyapunov-stable interval type-2 fuzzy PID controller design for ultra-lift Luo converter

Abstract The ultra-lift Luo converter is a fourth-order DC-DC step-up converter capable of providing high voltage gain with low voltage and current ripples. However, its nonlinear dynamics, switching behaviour, and parametric uncertainties make controller design a challenging task. This paper proposes a Lyapunov-stable interval type-2 fuzzy PID controller for output voltage tracking of the ultra-lift Luo converter. The controller performance is investigated under step reference voltage changes, input voltage variations, and output capacitor uncertainties. A conventional PID controller is considered for comparison. Performance evaluation is carried out in terms of rise time, settling time, recovery time, overshoot/undershoot, and integral absolute error using a MATLAB/Simulink-based interval type-2 fuzzy logic toolbox. Simulation results demonstrate that the proposed controller achieves superior transient performance and provides enhanced robustness against parameter uncertainties compared with the conventional PID controller.