Switched inductor super boost converter with auxiliary charging mode for low duty operation in a DC microgrid

Abstract

For a number of applications including the power processing of low voltage renewable sources such as solar PV in grid connected systems, high gain voltage conversion is a basic requisite. A conventional boost converter will have diode recovery issues, increased current ripples, poor transient response, and low efficiency if it is being operated at high duty ratio beyond certain permissible limit. This paper discusses a new converter suitable for the mentioned application that uses three double-duty regulated switches, switched inductor–capacitor to deliver the required high voltage at a low duty cycle. This converter’s basic topology does not include complex circuitry such as transformers, coupled inductors, and cascaded/interleaved configurations. In addition, the proposed converter can operate in auxiliary charging mode, which improves the voltage gain and control flexibility while also expanding the duty ratio range. The converter in discussion has a high voltage gain, a low total voltage standing, a continuous input current, a wide range of duty ratios, and the ability to select the duty cycle as needed. The boundary conditions, as well as the CCM and DCM investigations of the proposed converter are explored. The experiment findings are used to validate the claims made in the theoretical analysis. A comparison with the available high gain DC–DC converters is made to justify the superior performance. A 200 W prototype of the converter is developed and tested in laboratory to validate its feasibility and behavior for the renewable based applications.