MODELLING AND CONTROL OF HALF BRIDGE AND NOVEL SIDO BOOST/BUCK DC-DC CONVERTER SYSTEMS

Abstract

The rapid advancement in power electronics has driven a significant demand for efficient, reliable, and precise regulation methods in DC-DC converters. This thesis addresses this demand by focusing on two distinct yet complementary areas of DC DC converter technology: the half-bridge DC-DC buck converter and the single input dual output (SIDO) step-up and step-down voltage converter. The first part of this study explores the closed-loop voltage mode regulation of a half-bridge DC-DC buck converter. This converter is renowned for its exceptional load regulation abilities, achieved through a comprehensive control strategy that ensures precise and reliable voltage regulation at the output. The approach involves deriving a mathematical model, employing state-space averaging and linearization methods, and assessing the open-loop bode plot with various input voltage dividing capacitors. This detailed analysis highlights the superiority of closed-loop voltage mode control in maintaining target output voltage amidst load changes and disturbances. Notably, the proposed controller demonstrates stable output voltage with improved transient response and decreased steady-state error compared to open-loop control. The second part of this thesis delves into the SIDO step-up and step-down voltage converter, emphasizing optimal voltage gain and the challenges posed by load and line variations. A detailed mathematical model of the SIDO converter is developed to elucidate its behavior under diverse operating conditions. The study places particular importance on voltage gain characteristics and the converter's performance in varying load and line scenarios. To enhance control and stability, a Proportional-Integral (PI) controller is designed and optimized using MATLAB, ensuring efficient regulation of output voltages. Experimental validation underscores the control strategy's effectiveness, showcasing enhanced voltage regulation, reduced output voltage ripples, and improved transient response. By integrating small signal modelling, voltage mode control, and the PI controller methodology, this research offers significant contributions to the fields of half-bridge buck converters and SIDO converters. The findings presented herein advance the understanding and application of these converters in power electronics, providing valuable insights for efficient power conversion in various system.