Bidirectional DC to DC Converter for Battery Charging / Discharging Operation

Abstract

Bidirectional DC-DC converters are used to transfer the power between two DC sources in either direction. These converters are widely used in applications, such as hybrid electric vehicle energy systems, uninterrupted power supplies , fuel-cell hybrid power systems , PV hybrid power systems , and battery chargers . Bi-directional DC-DC converter suitable for battery charging application with the isolation. There are two modes of operation in the battery chargers. 1) Charging mode: In this mode of operation it gets charged from the supply. 2) Discharging mode: In this mode it will feed to supply grid from the battery. Bidirectional DC to DC converter also provides a isolation with the help of high frequency transformer. A bidirectional DC-DC converter ensures that the proper charging voltage is supplied to the energy storage unit. Adequate charging and dis charging mode of operation for 310 V, 25A battery.This bidirectional DC to DC con- verter should be able to charge and discharge the battery range from 120 AH to 75 AH.Bidirectional converter should be able to deliver 60-310 V in charging mode.While it should be able to feed the 650 V when battery level is between 60 V to 310 V.In discharge mode additional boost converter or buck-boost converter required to boost up the voltage.But with the help of PWM method for H-bridge is used to achieve criteria thus eliminates the requirement of additional converter.