Modeling and control design of a non-ideal non-inverting buck–boost converter using a Type III compensator and logic switching

This paper proposes a unified modeling and control framework for a non-inverting DC–DC buck–boost (NIBB) converter operating under practical non-ideal conditions. A non-ideal small-signal model is developed by incorporating parasitic resistances and semiconductor voltage drops, enabling a more accurate representation of converter dynamics than conventional ideal models. The state-space averaging method is employed to derive the small-signal transfer functions for different operating modes. Based on the obtained model, a Type III compensator is systematically designed to improve phase margin, bandwidth, stability, and transient response. To ensure reliable operation over a wide input-voltage range, a hysteresis-based logic switch using Schmitt triggers is introduced to achieve smooth transitions among boost, buck–boost, and buck modes while preventing undesired frequent switching near transition boundaries. The proposed approach is validated through Software-in-the-Loop (SIL) simulations in the MATLAB/Simulink environment. Simulation results demonstrate stable voltage regulation, smooth mode transitions, and enhanced dynamic performance under varying operating conditions and load disturbances.