Voltage Lift Switched Inductor Double Leg Converter with Extended Duty Ratio for DC Microgrid Application

Abstract

In a DC microgrid, while integrating the low voltage sources such as Fuel cells and photovoltaics, an efficient DC-DC converter is crucially needed. Contributing to a high voltage whilst being operated on a low duty ratio is among the demanded features of the converter. For high voltage applications, the conventional converters are to be operated beyond the prescribed range of the duty ratio which may result in various detrimental effects such as voltage spikes, increased current ripples, and reduced efficiency. In this paper, a voltage lift switched inductor double leg converter (VLSIDL) has been proposed. This novel converter has the feature of attaining a very high voltage without using any complex circuitry such as transformer, multiple voltage lift circuits, cascaded or parallel structure, etc. This particular converter has three switches that are operated in three modes with two different duty ratios. Double duty control offers flexibility in the selection of duty ratio for a particular output voltage and a significantly high gain is easily attained. The double duty ratio not only provides an extended range but also improves the efficiency and performance of the converter. The steady-state analysis of the proposed converter is done analytically and the same is verified through the hardware prototype.