Design of wide input voltage range high step-up DC-DC converter based on secondary-side resonant tank full bridge LLC

Abstract

Battery are widely utilized in uninterruptible power supply (UPS) to provide the power temporarily during power failure. In applications up to a few kilo watts, low voltage battery stack are typically used since it is not economically feasible to use high voltage battery stack in such application. To interface the battery to the dc-link of the UPS, power electronic converter are widely used. Due to the wide voltage variation at battery terminal that are mainly caused by battery state of charge and battery stack current, power converter for battery application are required to be capable to interface with wide battery voltage range. In this paper, a wide input range high step up converter was designed based on LLC converter. To significantly reduce the resonant capacitor current, secondary side resonant tank LLC converter was proposed. Finally, a 2 kW prototype was designed for 36 V∼ 72 V input voltage and 410 V output voltage, built, and from experimental test 93.59% peak efficiency was measured.