Microcontroller based bidirectional buck–boost converter for photo-voltaic power plant

Abstract

A common configuration for a stand-alone PV power system may consist of three converters: a buck converter for the PV panel to charge the battery, a boost converter for the battery to discharge to the load and one for the load voltage regulation. Such a system requires a coordinated control scheme for three converters which can be complicated. A simple structure for a stand-alone PV plant consists 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. In this 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 mode transition, buck to boost and boost to buck mode automatically based on source voltage. Hardware implementation has been done using microcontroller (8051). Keywords: Battery, Microcontroller, DC to DC converter, Solar panel, Battery control strategy