Analysis and design of a converter based on noncascading structure

Abstract

In the present work, a converter employing two noncascading structures, combined in a single circuit, is presented. The power stored by the storage element is transferred to two subconverters by means of two storage capacitors that complement each other. The stress on the main power switch is of interest as it reduces as the load falls, which in turn reduces the power loss. By means of the storage elements, the input power factor as well as the load transient response can be improved simultaneously. The overall efficiency is high because the amount of power processed twice decreases. There is no need for tradeoff between the input power factor and load transient response because both the capacitors can serve two purposes. The important feature of the circuit is that the capacitor voltages remain almost constant and reduce as the load decreases, which results in small variation in duty ratio with a fall in load and hence better utilization of the switch. As an illustration, a 65-W, 18.5-V circuit is presented.