Dynamic performance improvement schemes in buck and buck boost power electronic converters

Abstract

The conventional Buck and Buck-Boost converters, two fundamental topologies in power electronics, are widely used in applications such as IoT devices, renewable energy systems, and portable electronics due to their simple design and ease of control. While compensators like PID, Type-II, and Type-III are commonly employed to regulate output voltage under various external disturbances, they often fall short in achieving the fast transient response demanded by many modern applications. This research focuses on enhancing the transient response of DC-DC converters, specifically the Buck and Buck-Boost converters. In the voltage-mode control domain operating in continuous conduction mode, the dynamic response of conventional compensators is constrained by the bandwidth of the error amplifier. To address this limitation, two innovative approaches are proposed: an Input Voltage Feedforward Scheme (IVFS) for the Buck converter and an Adaptive Sawtooth Height Control (ASHC) scheme for the Buck-Boost converter. Additionally, a state-space model of the conventional Buck and Buck-Boost converters, incorporating all significant active and passive parasitics, is developed to improve the accuracy of dynamic analysis and control design. The growing demand for space efficiency, improved performance, and cost reduction driven by the trend toward miniaturization necessitates the development of multi-input, multi-output (MIMO) converters. A significant portion of this research is dedicated to designing a novel topology: a two input, bipolar three-output (DITO) Buck converter. While traditional single-inductor, multiple-output (SIMO) converters are prevalent, their reliance on time-multiplexing control leads to challenges such as cross-regulation, increased component stress, and limited suitability for certain applications. To support the analysis and design of the proposed topology, a detailed state-space averaged model of the DITO Buck converter is developed. To overcome the limitations of SIMO, coupled inductors (CI) are utilized.