SWITCHING FREQUENCY EFFECTS AND EFFICIENCY ANALYSIS OF QUADRATIC BUCK CONVERTER FOR LOW OUTPUT VOLTAGE AND HIGH CURRENT APPLICATIONS

Abstract

The Quadratic Buck Converter is well known for its voltage conversion ratio has a quadratic dependence on duty cycle. In dc-dc converters it is prominent that the transient performance can be improved by increasing the switching frequency of the converter, and also it is economical due to decrease in converter size. But the adverse effect is efficiency degradation due to increased switching losses. This paper will throw light on switching frequency selection and efficiency analysis of the quadratic buck converter (QBC) for low output voltage and high current applications. Initially the modeling of the quadratic buck converter is presented using state space averaging technique. The conduction loss and switching loss of various power semiconductor devices are inscribed with formulae. The simulation of the quadratic buck converter is performed with digital average current-mode (ACM) controller using PSIM software. The programming related to switching frequency selection and efficiency analysis is carried out using MATLAB software in order to obtain the performance characteristics of QBC. A compromise is always necessary in between the converter efficiency and transient response.