Modelling and Control of a Buck Converter Using State-Space Averaging and Classical Feedback Techniques

Abstract

This study presents the modeling, control design, and performance analysis of a DC-DC buck converter using state-space averaging techniques. Buck converters are essential in modern power electronics for regulating DC voltages in renewable energy and electric vehicle systems. The paper first introduces the basic operation of buck converters and emphasizes the need for voltage regulation through closed-loop control systems. A state-space averaged model is derived to simplify the nonlinear switched dynamics, enabling a more effective analysis and controller design. The small-signal transfer function from the duty cycle to the output voltage is obtained to support control development. In addition, the Proportional-Integral (PI) control based on the frequency-domain method was explored. The PI controller was tuned to achieve various phase margins and is evaluated through Bode plots, step responses, and performance metrics, revealing trade-offs between overshoot, settling time, and steady-state error. A complete simulation of the controlled buck converter verifies its ability to maintain a stable output voltage across wide input voltage variations. The results validate the effectiveness of state-space averaging in control design and highlight the robustness of feedback systems in power electronic converters.