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United Arab Emirates University College of Engineering Department of Electrical Engineering Graduation Projects Unit. Remote Management and Performance T uning of Photovoltaic S olar P anels . Group Members:. Advisor: Dr. Atef Abdrabou. Outline. Detailed Design.
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United Arab Emirates University College of Engineering Department of Electrical Engineering • Graduation Projects Unit Remote Management and Performance Tuning of Photovoltaic Solar Panels Group Members: Advisor: Dr. AtefAbdrabou
Outline • Detailed Design. • Selection changes in GP2 • Measuring PV parameters. • Acquisition of PV parameters. • Controlling PV inclination. • The management software. • Graphical user interface. • Photovoltaic test. • Xbee test. • Ethics, healh and saftey. • References. • Introduction. • Objectives. • Project objective. • General Overview. • Project specs. • Summary of Achievements in GP I. • Photovoltaic panel selection. • Motor selection. • Motor driver selection. • Communication part selection.
Introduction: • This project aims at designing and implementing a remote management system for solar panels using wireless communications. • The management system can be used to control the PV panel and to tune its performance. • The system shall state the parameters of PV panels at different inclination.
Project Objectives: • Design and implement a remote management system of photovoltaic solar panels using wireless communications. • Measure the PV panel parameters at the remote part such as: power, current and voltage. • Do performance tuning by changing the inclination of PV. • Compare the different values of each PV inclination to determine the best inclination of the PV panel at different times of the year.
Project Specs: • Reduced power consumption • Reduce the size of the Photovoltaic panel, therefore, reduce its weight. • Motor sizing (which is based on the size and weight of PV panels). • Motor speed must be slow to get the accurate tilt and inclination of PV panel. • Transmission range for the communication system has to be reasonable but not too big
Project Specs: • Reliability of the PV panel cells. More efficiency means more reduction in size. • Cost: A limited budget was assigned to this project so cost estimation is one of the most important constrains. • The communication system must be able to collect the required data and send it to the software in management part. • Analog to digital conversion should be done before sending the data over wireless communication. • The PV panels stand has to be able to move, not fixed. • The motor has to be able to move back and forward (with precise angles, for that high speed is not required). • The system must be environment friendly and safe.
Summary of Achievements in GP I: • Photovoltaic panel
Summary of Achievements in GP I: • Stepper Motor
Summary of Achievements in GP I: • Stepper motor controller and driver • We selected an Atmel microcontroller (Atmega324). • We selected a stepper motor driver from pololu.
Summary of Achievements in GP I: • Communication part
Selection changes in GP2: • Thin film photovoltaic panel was chosen as our PV in GP2 because: • Its has very light weight, only 1.5 kg. • It has no frame. • Under different perturbation conditions ( such as temperature) thin film has best efficiency. • Its is not made of class. • Its flexible andeasier to carry from place to place.
Selection changes in GP2: • Easy driver stepper motor from spark fun, was selected for GP2 because: • The pololu stepper motor had a very small potentiometer, which used to affect the motor dramatically; it was inefficient and very badly made.
Measuring PV parameters: • Two analog inputs capture the voltages. • Voltage divider will be done to reduce the amount of voltage coming from the PV as Xbee work on 3.3V only. • The following equation was used to determine the values of the resistors used: • Vout= 3.3 (Xbee rated voltage) • Vin = 20 (from PV panel) • Vout/Vin = R2/R1+R2 = 3.3/20 = 33/200 • R2 = 33 ohm , R1 = 167 ohm.
Acquisition of PV Parameters: 7E start delimiter 00 0C Length Bytes 83 API Identifier Byte for 16bit DIO data. 56 78 Source Address Bytes 2E RSSI Value Bytes 00 Option Byte 02 Sample Quantity Byte 00 18 00000000 00011000 channel indicator* 00 18 Sample data DIO 3 & 4 00 sample data 1 18 sample data 2 36 Check sum . • From the UART output of the Xbee transceiver at the management unit the amount of voltage of the PV panel will be known. • As the data in UART will be in API format , so if the output came out to be: 7E 00 0C 83 56 78 2E 00 02 00 18 00 18 00 18 36, the UART API data stream can be broken down. • From the bits lined up in AX and DX, we can know the value of the voltage coming from the PV panel.
Controlling PV inclination • When an angle input is entered by the user in the management part, the microcontroller will change this value to steps and send it to the motor driver to drive the motor depending on different angle values. • Each pulse from the microcontroller moves the motor one microstep. • If the driver is adjusted to full step mode, this means the motor will do 200 microsteps per revolution. Each microstep is 1.8 degrees. • For example, in the quarter step mode, the motor will do 800 microsteps to complete one revolution, which means it will do 1.8/4 degree per microstep. • Suppose we configured our driver for quarter step and we want the motor to run 3.6 degrees, then the microcontroller will generate 8 pulses only. This will turn the motor 8 microsteps = 1.8/4*8= 3.6 degrees and stop.
The management software • The remote part Xbee will send the management part Xbee the values of the PV voltage, these values will be saved on text file. • The visual basic software will open text file, take the value of voltage and resistor to calculate the current and power values for several hours a day at different positions of PV. • The values will be compared and displayed to the user as graphs.
Xbeetest: • The steps of the Xbee test range were : • Connect one xbee with its USB interface and then to the personal computer (PC1) • The other xbeeisconnected to a USB cable after cutting one terminal of the cable and the other terminal is connected to the second personal computer (PC2). • Then we need to connect as we see in figure.
Xbee test: • After the second xbee is connected to another PC via USB cable the following procedure were done: 1. Open XCTU software in both computers. 2. Fix the transmitter in one location and move the receiver away from it. 47 3. Use the XCTU chat between two computers and check that the receiver receives whatever we transmit in the transmitter. 4. When we stop receiving record this distance and this is the range of xbee. • The results that got from this test if the two xbee face to each other were : • Indoor = 12 meter, outdoor approximattely= 19 meter • On other hand results that got if the one of xbee up the other were • Result indoor= 6 meter, outdoor approximately = 18 meter.
Ethics, Health and environment: • Some years ago, sociologist Raymond Baumhart asked business people, "What does ethic mean to you?" [18] Among their replies were the following: • "Ethics has to do with what my feelings tell me is right or wrong." • "Ethics has to do with my religious beliefs." • These replies might be as our own, in the other hand it might be different, as the definition of “ethics” is hard to define, and the beliefs and vision people have about ethics are wobbly. • But for us ethics is to: • accept and take responsibility for our mistakes. • to be willing to do this in the face of harshest critics. • not to cheat from other projects, not to copy and paste • to work as hard as we can to provide a safe prototype for the user to use without being scared to get harmed or injured. • We treat the user as a family of our own and his safety is important. • We are required to be honest in the budget that we are using and give critical measurements without increasing or decreasing any amount. • We must be honest in our prototype measurements and testing, even if it’s not working correctly. We are trusted engineers and we are working to keep this trust gained.
Ethics, Health and environment: • Advantages: • Our project helps to improve the performance of one of the most widely used renewable energy resources, which are photovoltaic panels. • PV installations can operate for many years with little maintenance or intervention after their initial set-up, so after the initial capital cost of building any solar power plant, operating costs are extremely low compared to existing power technologies. • When grid-connected, solar electric generation replaces some or all of the highest-cost electricity used during times of peak demand (in most climatic regions). This can reduce grid loading, and can eliminate the need for local battery power to provide for use in times of darkness. Grid-connected solar electricity can be used locally thus reducing transmission/distribution losses. • Disadvantages: • solar electricity is it is more expensive than most other forms of small-scale alternative energy production and it is not produced at night and is much reduced in cloudy conditions. Therefore, a storage or complementary power system is required. • It depends on the limited power density of the location's insulation. Solar cells produce DC which must be converted to AC (using a grid tie inverter) when used in existing distribution grids. This incurs an energy loss of 4–12%.
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