Microcontroller based bidirectional buck boost converter for photo voltaic power plant

A common configuration for a stand-alone PV power system may consist of three converters: a buck converter for the PV panelto charge the battery, a boost converter for the battery to discharge to the load and one for the load voltage regulation. Such a systemrequires a coordinated control scheme for three converters which can be complicated. A simple structure for a stand-alone PV plantconsists of a PV array, a battery unit, and its associated bidirectional converter which is a combination of a buck and boost converter.When controlled properly the system can provide uninterrupted power to the load, despite the intermittent availability of sunlight. Inthis paper complete design of the converter is carried out and the simulation has been performed using Psim. From the simulation,the graphs are presented to show the converter working in buck mode and boost mode. Controller is designed to take care of modetransition, buck to boost and boost to buck mode automatically based on source voltage. Hardware implementation has been doneusing microcontroller (8051).