追踪mppt(Arduino)

International Journal of Computer Applications (0975 – 8887) Volume 76– No.8, August 2013 21 Design and Implementation of Photo Voltaic System: Arduino Approach Neeraj Vijay KaleDepartment of Electronics Engineering, Walchand Institute of Technology, Solapur Maharashtra, India, 413006. Prashant Shivasharan MalgeDepartment of Electronics Engineering, Walchand Institute of Technology, Solapur Maharashtra, India, 413006. ABSTRACT Photovoltaic (PV) is a renewable energy source and has become an important source of power for a wide range of applications. Design and implementation of an Arduino based Photovoltaic system are presented in this paper. Proposed system includes Maximum power point tracking (MPPT) technique, sun tracking technique to generate maximum power from PV panel and monitoring software for monitoring the performance of Photovoltaic system. The paper describes the design of MPPT unit, sun tracking unit and development of monitoring software for PC. Finally experimental results validate the performance of the proposed system. Keywords Maximum Power Point unit, Sun tracking unit, Monitoring Software. 1. INTRODUCTION The basic need for development and existence of human life is an energy. Fossil fuels (Coal, oil and natural gas), hydroelectric power and nuclear power are the commercial sources of energy. [2] Total world consumption of energy is increasing at an alarming rate year after year. According to Key World Energy Statistics 2012 published by the International Energy Agency (IEA), total world final consumption of energy has increased from 4672Mtoe (million ton of oil equivalent) in 1973, to 8677Mtoe in 2010. On the contrary, the fossil fuels are rapidly depleting and reserves of the fossil fuels are gradually coming to an end. Because of the increased world total consumption of energy and depletion of resources the cost of the commercial resources has achieved high hike. [2]. Because of these problems, the focus is now shifting towards renewable energy sources. Solar energy is a renewable energy source that can lead us away from our commercial energy sources. Solar energy is clean, renewable and sustainable unlike fossil fuels such as coal, oil and natural gas and is also sustainable.Photo voltaic systems have two major problems; the conversion efficiency of electric power generation is very low about 10-24%[3], and get reduced under low irradiation conditions. PV panels have a nonlinear voltage-current characteristic [4], with a distinct maximum power point (MPP), which depends on the environmental factors, such as temperature and irradiation [3]. In order to continuously harvest maximum power from the solar panels, they have to operate at their MPP despite the inevitable changes in the environment. MPPT strongly tracks this operating point to generate maximum power from PV panel. Since the Earth rotates, and orbits around the sun, the relative position of the sun changes and is a major factor in the performance of PV systems [13]. To generate the maximum power from solar panel, solar panel must be aligned perfectly towards the sun; hence MPPT is used in conjunction with a mechanical sun tracking in the proposed system. To understand the performance of PV system monitoring software is developed. For proposed system Arduino is used. Arduino is an open source electronic prototype platform that consist of 8-bit Atmel AVR microcontroller such as Atmega328. More information about Arduino is available at http//Arduino. cc. The outline of the paper is as follows. The design of maximum power point tracking and sun tracking is described in section 2 and 3 respectively. Section 4 describes monitoring software. Experimental results are presented in section 5. Finally section 6 concludes the paper. 2. DESING OF MAXIMUM POWER POINT TRACKING This section describes maximum power point tracking technique and its implementation in the proposed system. 2.1 Maximum Power Point Tracking (MPPT) The PV cell V-I characteristic is nonlinear and varies with irradiation [4]. Maximum Power point i.e. PMAX of PV modules is defined as the point on IV curve where we get maximum current and voltage [7] as shown below in Fig.1 at VMP and I MP maximum power of PV panel is located, VMP and IMP are the maximum voltage and current respectively. Maximum power point tracking is the control technique that maintains the PV modules operating point at its Maximum Power Point. MPPT technique operates the PV module in a manner that allows the module to produce all the power it is capable of. The terminal voltage of PV panel is adjusted so that the maximum power can be extracted. MPPT technique involves the design of DC to DC buck converter. MPPT algorithm is embedded in Arduino which adjust the duty cycle of DC to DC converter according MPPT algorithm by comparing the voltage and current of PV module [5]. Different methods of MPPT are available such as Perturb-and-observe (P hence power generated from a PV panel for position B is less than that for position D. That is in order to generate maximum power from PV panel; panel must have to be aligned with the sun. Even a small angle variation causes a larger drop down in power. Position A Position B Position C Position D Fig 14: Four different position of PV panel with Respect to sun position. Fig 15: Plot of output power for four different positions of PV panel. 5.2.1 Optimum Angle of PV Panels by Month for Solapur City: Table 2 shows the optimum angle for PV panel in degrees from vertical by month. Optimum angle PV panel varies throughout the year, depending on the seasons and location. These solar angles are calculated by using solar-angle-calculator available at http://solarelectricityhandbook.com International Journal of Computer Applications (0975 – 8887) Volume 76– No.8, August 2013 26 Table 2. Optimum angles of PV panel by Month Jan Feb Mar Apr May Jun 56° 64° 72° 80° 88° 96° Jul Aug Sep Oct Nov Dec 88° 80° 72° 64° 56° 48° Table 3 shows output generated for different angles of PV panel with respect to vertical. Since readings are taken on 28/06/2013, from Table I optimum angle of PV panel for the month June is 96o. From Table II Maximum power is generated when PV panel is at an angle in between 80o to 96o with respect to vertical.Table 3. Reading taken on 28/06/2013 at 1:30pm Angle Current Voltage Power 0o 0.99A 18V 17.82W 16o 1.09A 18V 19.62W 32o 1.98A 18V 35.64W 48o 2.16A 18V 38.88W 64o 2.25A 18V 40.5W 80o 2.26A 18V 40.68W 96o 2.26A 18V 40.68W 112o 2.24A 18V 40.32W 128o 2.14A 18V 38.52W 144o 2.04A 18V 36.72W 160o 1.94A 18V 34.92W 6. CONCLUSION: This paper describes the design and implementation of MPPT techniques in conjunction with mechanical sun tracking technique and development of monitoring software for PC. Experimental results conclude that MPPT based charge controller generates average 12% more power as compared to PWM based charge controller. MPPT based charge controller increases battery health by charging the battery at constant charging current and avoiding overcharging. Maximum power is generated when PV panels are perfectly aligned towards sun i.e. In order to generate maximum power from a PV panel, the panel must have to be aligned with the sun. Even a small angle variation causes a larger drop down in power. Thus MPPT in conjunction with mechanical sun tracking generates more power as compared PV system that contains fixed panel and PWM based charge controller. 7. REFERENCES [1] Handbook on Energy Conscious Buildings by J.K. Nayak J.A. Prajapati- May 2006. [2] Fossil Fuels and Pollution: The Future of Air Quality(book)- Julie Kerr Casper [3] Solar Electricity Handbook - 2013 Edition. [4] Solar Cells and Their Applications by By Lewis M. Fraas, Larry D. Partain. [5] Thin Film Solar Cells: Fabrication, Characterization and Applications by Jef Poortmans, Vladimir [6] Evaluation of Micro Controller Based Maximum Power Point Tracking Methods Using dSPACE Platform by Yen-Jung Mark Tung, Dr. Aiguo Patrick ,Dr. Nirmal-Kumar Nair. [7] Fundamentals of Photovoltaic Modules and Their Applications-Gopal Nath Tiwari, Swapnil Dubey [8] Techniques for Maximizing Efficiency of Solar Energy Harvesting Systems by Pai H. Chou and Sehwan Kim. [9] Power Electronics Handbook By Muhammad Rashid. [10] Electronic Devices and Circuit Theory By Nashelsky [11] Issa Bataresh, “ Power Electronic Circuits, ” John Wiley & Sons, Inc., 2004 [12] Buck-Converter Design Demystified, B Donald Schelle & Jorge Castorena. [13] Solar Tracking Systems: Leonard L. Northrup Jr [14] Servo motor control - embedded-lab.com [15] Sensors and Transducers By Ian Sinclair IJCATM : www.ijcaonline.org