Alireza E. Khosroshahi - Department of Electrical and Computer Engineering University of Tabriz Tabriz, Iran
Amir Farakhor - Department of Electrical and Computer Engineering University of Tabriz Tabriz, Iran
Mehdi Abapour - Department of Electrical and Computer Engineering University of Tabriz Tabriz, Iran

This paper presents an improved battery charger structure which can be supplied from a Photovoltaic (PV) power system. The presented structure is based on conventional Sepic converter. The presented converter has a transfer characteristic of a buck/boost converter. Therefore, the presented converter is able to extract the maximum power from the PV power system even in extreme situations and charge the battery efficiently. Continuous smooth input current of the presented converter also makes it suitable for PV generation systems. There are two charging modes for the presented converter; pulsating output current and constant voltage. Pulsating output current mode happens when the state of charge (SOC) of the battery is below a certain value. Constant voltage mode is also active in the final stages of the battery charging. These two modes improves the charging efficiency. The simplicity of the presented circuit is also an advantage in industrial applications. Various simulations are carried out and the results are provided to prove the capabilities of the presented converter.

Battery Charger; Photovoltaic power system; Sepic converter