A Solar MPPT Technique for Battery Charging Applications
- February 21, 2018
- Posted by: RSIS
- Categories: Electrical and Electronics Engineering, Engineering
International Journal of Research and Scientific Innovation (IJRSI) | Volume V, Issue II, February 2018 | ISSN 2321–2705
A Solar MPPT Technique for Battery Charging Applications
Dr. Sanjay Lakshminarayanan
Department of Electrical and Electronics Engineering, B.M.S. Institute of Technology, Bengaluru, Karnataka, India
Abstract: In this paper it is shown that for charging batteries from solar panels, MPPT can be achieved by varying the duty ratio of the DC-DC converter feeding the battery so that the average battery charging current is maximized. Assuming negligible losses in the converter, this is equivalent to maximizing the power output of the solar panel as in traditional MPPT. A low power(10 W) prototype has been built with a buck-boost converter to charge a lead acid battery (12 V, 7AH), with an Arduino microcontroller to control the duty ratio. The method can be scaled up easily to control even Kilo Watts of power.
Index Terms—Batteries, Converters, Duty ratio, MPPT, Solar Panels.
I. INTRODUCTION
There is an ever-growing interest in the area of renewable energy. There is an effort to develop energy sources which are clean, efficient and low cost [1]. Solar energy has long been a key area of research and there is further acceleration of research in this area. Methods of storage of energy are alsoimportant and hence batteries are required to store solar energy produced during periods of strong sunlight [1][2]. Lead Acid batteries are still in vogue, though Lithium ion batteries are also being tried out, cost being the determining factor. Fig. 1 shows that renewable energy sources constitute only about 2% of the world’s energy production.
Modern solar cells are simply silicon PN junctions with some additional layers, which develop a potential drop when subjected to irradiation in the form of light [2]. The physics behind this is the photoelectric theory developed by Einstein. These cells maybe connected in series to increase the output voltage and in parallel to increase the output current capacity.
Solar panels are normally specified by the maximum power output, the open circuit voltage and short circuit current. Only 10% of the incident power is converted to electrical energy, though some costly cells can go upto 25% and are used in space applications to conserve weight [3],[4].
