Contemporary materials for semiconductor switches in an isolated bidirectional DC-DC converter using a closed loop system with linear quadratic regulator control

Abstract

This research seeks to create a novel bidirectional DC-DC converter capable of high step-up/down power transfer for diverse applications, such as grid systems, energy backup systems, fuel cell vehicles and hybrid electric vehicles. The converter features an inductor linked to an electric power grid to facilitate multi-layer energy conversion with galvanic isolation for improved voltage ratio and galvanic isolation. Notable among its features is this converter's capacity to recycle energy from a leaky inductor without needing additional snubber mechanisms or clamped circuits. To facilitate efficient operation, the converter employs power switches capable of soft switching both step-up and step-down modes. This option permits using MOSFETs with low on-state resistance, which is advantageous due to reduced voltage endurance at the primary side. This research explores the application of a linear quadratic regulator (LQR) for use with a constant frequency bidirectional DC-DC converter. Leveraging the high-order nature of converters, LQR controllers make full use of their potential by offering rapid dynamic response time, reliability and minimal changes in settling time for an array of operating conditions. Thorough analyses were carried out into the availability and stability conditions of an LQR controller in step-up mode using MATLAB/Simulink simulation results as evidence. This study also emphasizes the significance of performance and effectiveness in electronic power-switching devices, which rely heavily on material properties for operation. While silicon has traditionally been employed for these switches, advances in material science have seen wider band-gap semiconductors adopted to improve switching device performance. Therefore, this research encompasses selecting and implementing appropriate semiconductor materials into power electronic switches used by DC-DC converters.