IMPLEMENTATION OF STEPPER MOTOR CONTROLLED SOLAR TRACKING SYSTEM

Transcription

1 IMPLEMENTATION OF STEPPER MOTOR CONTROLLED SOLAR TRACKING SYSTEM Rathika Kannan #1, Kavitha.S #2 #1,2 Department of Electrical and Electronics Engineering, Saveetha Engineering College,India 1 rathikakannan06@gmail.com 2 kavitha.vijay10@yahoo.com ABSTRACT: Solar tracking system is done for improving the efficiency of the PV panel output power using stepper motor controlled tracking system. Solar energy is rapidly becoming an alternative means of electricity source. This is a system that controls the movement of a solar array so that it is constantly aligned towards the direction of the sun. The solar tracker designed and constructed in this paper offers a reliable and affordable method of aligning a solar module with the sun in order to maximize its energy output. The solar tracking system for positioning the solar PV panel in proper orientation with the sun to receive the direct radiation is designed.the prototype is designed using Arduino controller which controls the tracking system by communicating with the LDR s and stepper motor driver based on the movement of the solar radiation. The performance and characteristics of solar tracker device is monitored and the simulation is done using MATLAB. Keywords: MPPT(Maximum Power Point Tracking), LDR(Light Dependant Resistor), PV(Photo-voltaic) 1. INTRODUCTION The stepper motor controlled solar tracking system is mainly designed for improving the efficiency of utilization of solar power to a greater extent. Especially generating electricity directly from sunlight plays an important part. Taking into consideration, there are two major systems for tracking the solar energy namely Maximum Power Point (MPP) tracking and mechanical solar trackers for managing solar energy most appropriately and sensibly. MPPT is the acronym for Maximum Power Point Tracker, as the title recommends this device is built to take out maximum achievable voltage and power from the panel and produce it to the load. An MPPT will generally attempt to carry out two main behaviors: It would observe the solar panel maximum obtainable power. Moreover, it would monitor that the load would not make an attempt to hog the panel by getting rid of unwarranted or infeasible amount of watts often as a result of a short circuit or shunting of the output leads of the MPPT. Solar trackers can also be a mechanical systems manufactured to track the sun rays practically, indicating the solar panel keep on changing its surface orientation in accordance with the sun s shifting positions such that it retains a perpendicular angle with the sun rays the whole day. The above movement is carried out using motors and an LDR sensor circuit. The LDR sensor circuit detects the sun rays and the panel keeps tilting from east to west fraction depending on step angle. A solar tracker even offers to run the panel at overcast condition and adjust the panel for optimal angle of the sun rays.nishit kapadia[1] designed an intelligent low cost single phase solar inverter topology with two switches and the isolation requirement between control and employed a sine wave push pull inverter to reduce power and to decrease the cost. Maximum power point tracking algorithm to track the global peak (GP) under partially shaded conditions has been proposed by Hiren Patel [2]. By additional supervisory control using an external interrupt of the microcontroller the user can set the different periodic checking intervals under different weather conditions or seasons. Utomo et.all [3], developed an automatic Solar Tracker Robot (STR) to track maximum light intensity. The efficiency of the solar energy conversion can be optimized by receiving maximum light on the solar panel. Md. Tanvir et.all [4],conveyed a microcontroller based design methodology of an automatic solar tracker. Light dependent resistors are used as the sensors of the solar tracker. The design and implementation of automated, double-axis solar tracking mechanism[5], using embedded system to optimize the efficiency of overall solar energy output. Nikhil Patel [6] described about the automatic solar tracking in all weather conditions with the help of the microcontroller, [7] LPC2148 based improved structure of solar tracker using the ARM processor is implemented.the high performance closed loop boost Page No: 221

2 converter for solar powered HBLED lightning system is designed in [ 8] and in [9] Ben seddik,et.all proposed an implementation of boost converter for a resistive load using photovoltaic energy as a source.solar trackers are highly efficient and are a great fit for many smaller jobsites. Mechanical Solar Tracking System require unskilled worker and easy maintenance. It is been observed that the mechanical tracking was done for small prototype PIC16F84A with two degrees of freedom where double axis solar tracking mechanism had been implemented using embedded system design to optimize efficiency of overall solar energy output. Therefore, in this paper the design and construction of solar tracking system controlled by Arduino Uno R3 Atmega328p controller, which is capable of tracking the maximum intensity of light using LDR is explained. II. TRACKING SECTION The block diagram is divided into two parts. The first part is the tracking section. The second part is the converter and inverter section. In the block diagram of the tracking section, the first block is Light Dependant Resistor. It is connected to the Arduino microcontroller board. The controller is interfaced with driver unit for driving the stepper motor. Depending on the signals from the LDR the motor rotates either in clockwise or anti-clockwise direction. Fig 2. Block diagram of tracking section The block diagram of tracking section is depicted in Fig 2. Four LDR s are used in which one LDR is permanently mounted in east direction. The other three LDR s are fixed in a straight line such that depending on the intensity of each LDR the stepper motor rotates the panel in counterclockwise direction. When the sun is in east direction the first LDR senses the light that will have high intensity compared to other two LDR s. At that time the panel is rotated in clockwise direction and braking operation is performed when second LDR intensity goes high compared to first and third LDR. The panel is rotated from west to east during sunrise depending on the intensity of fourth LDR. III.CONVERTER AND INVERTER SECTION The solar tracker follows the sun from east to west. The solar tracking system is controlled by comparing the delivered amount of light on the LDR s. The solar cells convert solar energy into electrical energy. The electrical energy from the solar panel is stored in the battery. Electrical energy is in DC form. This dc voltage is boosted using dc to dc boost converter. PWM sine wave Inverter is used to convert dc voltage to ac form and the output is given to the load. From the mechanical tracking the output from solar panel is measure as (10-17V). The output voltage from the solar panel will be varying because of changing position of the sun. In order to maintain a constant supply to the converter, voltage regulator is used. The function of voltage regulator is to provide constant supply. Output voltage from solar panel will be varying from 10-17V. Voltage regulator provides constant 12V to Converter. DC to DC boost converter converts 12 volt DC voltage to 24 volt DC. This DC voltage is converted to AC voltage using inverter. Inverter output is sine coded PWM Page No: 222

3 pulses. This sine coded PWM pulses are converted into sine wave using low-pass filter. The block diagram of converter and inverter is shown in fig.3. Fig.3 Block diagram of Converter and Inverter section IV.RESULTS AND DISCUSSION The PV array module is simulated using a generalized photovoltaic model using MATLAB Simulink software package. Fig 4.1 shows the simulation circuit of PV cell module. A simple mathematical relation is used to model the nonlinear characteristics of solar cell is shown below. The simulation of solar cell is performed using the MATLAB software and current and voltage waveforms are obtained as shown in fig 4.2 and 4.3. The output current and output voltage is simulated and analyzed. The output voltage is found to be 12V and output current is 1.3A. Fig 4.1 Simulation circuit of PV cell module Fig 4.2 Output current waveform of PV module Page No: 223

4 Fig 4.3 Output voltage waveform of PV module The simulation circuit of Boost converter and Inverter is shown in Figure 4.4. The Voltage Measurement and the current measurement block acts as an interface between the SimPower Systems blocks and the Simulink blocks. The values measured by the voltage and current measurement blocks are converted into Simulink signals. Boost converter inductace value and capacitance value is 0.01mH and 120µF. The output of boost converter is 24V DC and Inverter is 24V AC. The output voltage is connected to resistive load. Fig 4.4 Simulation Circuit of Boost Converter And Inverter The simulation results of DC-DC Boost converter is shown in fig 4.5. The output voltage is boosted from 12v to 24V DC. Fig 4.6 represent the generation of sine PWM is shown. Here sine wave is the reference signal and triangular wave is carrier signal..the inverter output for full load condition is simulated at 1 sec in Fig 4.6 and RMS value of output voltage of inverter is obtained to be 24 V. Page No: 224

5 Fig 4.5 Output voltage waveform of DC-DC Converter Fig 4.6 Generation of PWM pulse Fig 4.7 Inverter output voltage waveform V. STAND ASSEMBLY The frame for the solar panel is made up of L shaped steel rod. The length is 0.95m and width is 0.38m. A square plate of dimensions 28x30 cm is made out of iron plate is fixed to the main structure at the height of 90cm from the base. The main frame is also made up of L shaped iron rod. Fig.5 illustrates stand assembly. The system has four LDR s in which one LDR is permanently mounted in east direction. The other three LDR s are fixed in a straight line such that depending on the intensity of each LDR the stepper motor rotates the panel in counterclockwise direction. When the sun is in east direction the first LDR senses the light that will have high intensity compared to other two LDR s. At that time the panel is rotated in clockwise direction and braking operation is performed when second LDR intensity goes high compared to first and third LDR. The panel is rotated from west to east during sunrise depending on the intensity of fourth LDR. The Specifications of the prototype is given in Table.1 Page No: 225

6 Specification Fig.5 Image of stand assembly Table 1 Components specification Solar panel Details Material Poly crystalline Output voltage 12V Output watts 10W Output current 0.58A Boost converter Input voltage 12V DC Input current 0.38A Output voltage 24 V DC MOSFET IRF840 MICROCONTROLLER Arduino Uno ATmega328p PIC16F877A BATTERY Lead-acid 24V 0.46A Stepper Motor Input voltage 12V Input current 2A RPM 600 Type Unipolar VI. CONCLUSION Implementation of stepper motor controlled solar tracking system is an efficient and feasible means of obtaining optimal solar energy from the sun. By constantly aligning the photovoltaic panel with the sun, it directly receives sunlight falling on its surface thereby utilizing maximum energy. The design and construction of Stepper motor controlled solar tracking system implemented is capable of tracking the maximum intensity of light. The power producing ability is not restricted to the angle of sun rays on the panel. Analyzing the efficiency of the MPPT with respect to the sun's actual delivering power, Mechanical solar tracking can harness almost 95% of the available solar energy at any instant throughout the day. Mechanical Solar Tracking System is more efficient than Electro-Mechanical Solar Tracking System. and cheaper compared to electrical tracking.also it is easy to maintain and installed in remote or dusty or rainy place to develop electrical energy or to produce heat energy for different applications. The further improvements can be made upon this initial design with a photo transistor and amplification circuit to improve the resolution and accuracy/precision of tracking. Page No: 226

7 REFERENCE [1] Nishit kapadia, Simulation and Design of low cost single phase solar inverter International Journal of Emerging Technology and Advanced Engineering Conference (IJETEA), Volume 2, Issue 1, February [2] Hiren Patel and Vivek Agarwal, Maximum Power Point Tracking Scheme for PV Systems Operating Under Partially Shaded Conditions IEEE Transactions on Industrial Electronics-Volume 55, [3] A.B. Afarulrazi, W.M. Utomo, K.L. Liew and M. Zarafi, Solar Tracker Robot using Microcontroller" International Conference on Business, Engineering and Industrial Applications, 2011 [4] Md. Tanvir Arafat Khan, S.M. Shahrear Tanzil, Rifat Rahman, S M Shafiul Alam, " Design and Construction of an Automatic Solar Tracking System International Conference on Electrical and Computer Engineering ICECE 2010, December 2010, Dhaka, Bangladesh [5] Nader Barsoum, Implementation of a Prototype for a Traditional Solar Tracking System", Third UK Sim European Symposium on Computer Modeling and Simulation, 2009 [6] Asit Mistry and Nikhil Patel, Design of Automatic Solar Tracking Based on Microcontroller International Journal for Technological Research in Engineering-Volume 1, [7] K.Sreenivasa Rao and M.Mahesh, ARM Based Solar Tracking System International Journal on Modern Engineering Research (IJMER)-Volume 2, [8] P.Sathya and Dr.R.Natarajan Design and Implementation of 12v/24v Closed Loop Boost Converter for Solar Powered LED Lighting System International Journal of Engineering and Technology, March [9] T. Abdelkrim, K. Ben Seddik, B. Bezza, K. Benamrane, Aeh. Benkhefila Experimental Study of Boost Converter PV Energy System International Journal of Electrical, Computer, Energetic, Electronic and Communication Engineering- 2013,Volume 7. Page No: 227