Implementation of battery charging and discharging system in photovoltaic system

Nowadays, the photovoltaic system is widely used, but the charging and discharging controllers only provide protection to avoid overcharge and overdischarge. The poor charging ability leads the battery to have poor lifetime. The battery charging and discharging system in this paper can realize the three-stage charging, achieve the rapid charging of the battery, and make full use of the battery capacity. At the same time, the system can choose two modes of discharging to avoid overdischarge, also it can make the bus voltage stable to meet other applications.