Free Essay

Sudia Arabia

In: Business and Management

Submitted By abo0od
Words 5462
Pages 22
KING FAHD UNIVERSITY OF PETROLEUM & MINERALS COLLEGE OF ENGINEERING ELECTRICAL ENGINEERING DEPATMENT Senior Project Final Report - 121 Design and Implementation for Maximum Power Point Tracking for Photovoltaic Generators Advisor: Dr. Chokri, Belhadj Ahmed Mufti 200717070 Ahmad Al-Shammari 200736450 Abdullah Al-Shehri 200739630 Abdullah Al-Omran 200832100 Abdulillah Al-Saaedi 200832820
15th of December, 2012

We would like to express our gratitude towards all the people who have contributed their precious time and efforts to help us in completing this project.
We would like to thank Dr. Chokri Belhaj Ahmed, our Project Supervisor for his guidance, support, motivation and encouragement throughout the period of this project.

We would like to thank Dr. Alaa El-Din Hussein Ahmed, for his precious time and efforts to help us in completing this project.

We would also like to thank the Department of Electrical Engineering for providing us with a good environment, facilities and the equipment to complete this project.

We are also grateful to the lab technician Mr. Edmana Abbas for support and help.

Solar energy has become an alternative source of energy. Several researches have been focused on the photovoltaic (PV) systems efficiency development and the availability of this technology. Today, PV power generation has gained more consequence due to its numerous advantages such as fuel free, no maintenance and environmentally green. This report gives a smart approach for the improvement of the PV control performances. Photovoltaic systems normally use a maximum power point tracking (MPPT) technique to nonstop deliver the highest possible power to the load when even when atmospheric condition change suddenly. In order to achieve this goal, a special interest was focused on both Perturb and Observe method and Open Circuit Voltage method. This report presents a complete study of the MPPT controller to assure a highest possible PV system performance. A DC/DC buck converter feeding a load is achieved. Results are given at the end of the report.

CHAPTER 1: INTRODUCTION 1 A. Solar Panels 1 B. Characteristics of the Panel 3 C. MPPT 4 D. DC-DC Converters 8 E. Cassy Lab 12
CHAPTER 2: TECHNIQUES 13 A. Perturb and Observe 13 B. Incremental Conductance 14 C. Open-Circuit Voltage 15 D. Short-Circuit Current 16
CHAPTER 3: PERTURBATION AND OBSERVATION METHOD 17 A. Theoretical 17 B. Experimental 19
CHAPTER 4: OPEN CIRCUIT VOLTAGE METHOD 23 A. Theoretical 23 B. Experimental 24

V Voltage
I Current
P Power
ISC Short Circuit Current
VOC Open Circuit Voltage
MPP Maximum Power Point
MPPT Maximum Power Point Tracking
PV Photo Voltaic
P&O Perturb and Observe k Constant of Proportionality
D Duty Cycle n Harmonic Variable
C Condition

Figure1. The Electric Field Created by Diffusion of Electron 2
Figure2. Power Curve in Two Days 3
Figure3. IV Characteristics of a Solar Panel 4
Figure4. PV Characteristics of a Solar Panel 4
Figure5. IV and PV Curves at Different Load Variations 6
Figure6. IV and PV Curves at 9:00 A.M 6
Figure7. IV and PV Curves at 9:00 A.M and 9:30 A.M. 7
Figure8. IV and PV Curves at 9:00 A.M, 9:30 A.M. and 10:45 A.M. 7
Figure9. DC Converters General Circuit 8
Figure10.Basic Circuit of a Buck 9
Figure11. MOSFET and Power Diode 10
Figure12. Function Generator and Oscilloscope 10
Figure13. Connections of a DC-DC Buck Converter 11
Figure14. Connection of a Buck Converter 11
Figure15. Example of some functions available in the CASSY Lab 12
Figure16. Characteristics PV array Power Curve 14
Figure17. Incremental Conductance 15
Figure18. P&O Algorithm Chart 18
Figure19. Cassy Lab Connection 19
Figure20. Condition of P&O 19
Figure21. Duty Cycle Formula 20
Figure22. Function Generator Settings in CASSY Lab 21
Figure23. Block Diagram of Voltage Based MPPT 23
Figure24. Function Generator for the Duty Cycle 24
Figure25. Output Voltage using Oscilloscope 25
Figure26. Function Generator in CASSY Lab 25 Figure27. Duty Cycle and Output Voltage without Capacitor and Inductor 26 Figure28. Duty Cycle and Output Voltage with Capacitor and Inductor 26 Figure29. Function Generator Using CASSY Lab 27 Figure30. Duty Cycle and Output Voltage with 500Hz Frequency 27 Figure31. Open Voltage Formula 28
Figure32. Output of DC-DC Converter with a Variable Load 29

List of Tables
Table I. Current, Voltage and Power Values at Different Load Variations 5
Table II. Major Characteristics of MPPT Techniques 16
Table III. Summary of P&O Algorithm 17
Table IV. Condition Results of P&O 20
Table V. Duty Cycle Results 22

Renewable energy lately increases rapidly, due to the crisis of nonrenewable resources. Fortunately, there are different kinds of sustainable energy that friendly to the environment, such as solar energy, wind energy, biomass energy, geothermal energy and much more. In this project we will focus only on the solar energy, and particularly in the techniques of maximum power point tracking (MPPT) to increase the efficiency of the photovoltaic system.

There are studies shows that we can deliver only 30%-40% solar energy into electrical energy. Realistically, they only reach efficiency from 10% to 17%. However, in this part maximum power point is necessary to increase the efficiency of the photovoltaic cell, and there are different techniques that it will mention later on this report. First of all we have to understand the concept of converting light to electrical energy.

A. Solar Panels
The photovoltaic cell (PV) made of semiconductors (e.g. Silicon, Gallium arsenide). Basically; the PV cell is a p-n junction, the donors with more valence electron exist in the n- side, and the acceptors with less valence electron (holes) exist in the p-side. Next, the electrons in n-side diffused in the p-side to achieve the equilibrium in the junction, and the moving of electrons creating behind it an electric field; this electric field pulls the electrons and holes in opposite directions which creating current flow in one way only. The solar system built by many PV cells that could be connected in parallel or in series, depend on the function of the system used for. [1]

Figure(01): The electric field created by diffusion of electrons [2]

Silicon is the most widely used material for making PV panels. Although other materials can be used for making PV panels, Silicon features with the high availability in the Earth’s crust. Silicon and other semiconductors can be crystalline, multicrystalline, polycrystalline, and microcrystalline (amorphous). [1]

Crystalline (Monocrystalline silicon):
Crystalline silicon has an ideal structure of silicon atom, which makes it the most efficient ones. However, it is the most expensive ones, because it requires careful, and slow manufacturing process. [2]

The structure of multicrystalline is random, so the efficiency is lower than crystalline silicon. In the other hand, the process of manufacturing is simpler and cheaper. [1]

Amorphous silicon is the non-crystalline form of the silicon atom. The manufacturing process is the simplest, which also makes it the cheapest one. However, amorphous silicon absorbs photons better than crystalline, so this ability makes it preferred over crystalline in the cloudy days. [3]

B. Characteristics of the Solar Panel:
The university has two solar panels and we used both of them in our project.

Figure (02): The solar Panels above building 59 at KFUPM
Here is a table of the solar panel characteristics:

Table I: Solar Panel Characteristics

Solar Panel | Manufacturer | National Solar Systems | Model | NSS-24150M | Max System Voltage | 1000 V | Stand test condition | 1000 W/m2 , AM1.5 , 25C | Max Power | 150 W | Max Power Voltage | 36 V | Max Power Current | 4.61 A | Open Circuit Voltage | 43.2 V | Short Circuit Current | 4.49 A | Net Weight | 16.0 Kg | Size (L\B\T) | 1580,808,46 mm | Out Tolerance | ±5 | Made in | Chine |

We used one of the panels to measure the power in the course of two days. The days had different irradiations due to the weather conditions. The power can be seen at figure ().

Figure (03): Power Curve in two days
As we can see from the graph, the power was calculated directly from the PV panel for approximately 2 days. The 2 days were a little bit cloudy and so the maximum power we got was approximately 80 W. Our PV panel gives us approximately 130 W on a very good day.

C. Maximum Power Point Tracking
It is not easy to improve the efficiency of the PV panel and if we want to use better equipments, that is going to increase the price of the installation. That’s why it is easier and cheaper to use the MPPT which stands for Maximum Power Point Tracking. MPPT system is necessary because PV arrays have a non linear voltage-current characteristic with a unique point where the power produced is maximum and this point depends on the heat and irradiation conditions [4]. MPPT Algorithm’s main job is to obtain the maximum power from a PV panel to ensure that the PV panel is always producing power as close to its I-V curve as possible[6].

Figure (04): IV characteristics of a solar panel [5]

Figure (05): PV characteristics of a solar panel [5]

As we can see from the plots, the power depends on the current and voltage characteristics. So in order to get the highest possible power to supply our load we must track the maximum power point by using a special algorithm. There are a lot of different algorithms for the MPPT, most of them are completely different from each other and use different algorithms and have different efficiencies. Examples of such algorithms are Perturb & Observe, Incremental Conductance, Fuzzy Logic Control, Open Voltage Circuit and so on. In this project we will use the Perturb & Observe and Open Voltage Circuit methods to find our MPPT.

You can see the results with no MPPT system in the Table and plot below. First we connected our circuit without using the DC-DC converter and we changed the resistance manually. Here is a table and a plot below and of the PV and IV curves:

Table II: Current, Voltage and Power Values at different load variations P (W) | V (Volt) | I (A) | R (Ω) | 48.7584 | 33.86 | 1.44 | 22 | 83.571 | 31.3 | 2.67 | 11 | 95.31 | 27 | 3.53 | 7.3 | 87.02 | 22.9 | 3.8 | 5.5 | 74.844 | 18.9 | 3.96 | 4.4 | 63.282 | 15.9 | 3.98 | 3.67 | 53.1275 | 13.45 | 3.95 | 3.14 | 47.0842 | 11.86 | 3.97 | 2.74 | 42.4935 | 10.65 | 3.99 | 2.44 |

Figure (06): IV & PV Curves at different load variations
By using the load variation in the load panel, we connected the circuit directly without using the DC-DC converter to notice the radiation and load effects and trying to find the MPPT location. The load was varying from 500 Ω to 0 Ω and the plots were better than we connected the loads manually.

Figure (07): IV & PV Curves at 9 A.M.

We started calculating at 9 A.M. and it was cloudy so the maximum power we got was 52 W and the ISC was approximately 2.1 A

Figure (08): IV & PV Curves at 9 A.M. and 9:30 A.M.
After it became less cloudy the current increased from 2.1 A to 3 A and the power increased 27% to 71W. That shows how a radiation severely affects the power.

Figure (09): IV & PV Curves at 9 A.M. and 9:30 A.M. and 10:45 A.M.

Now that the weather is even less cloudy than it was at 9:30 A.M., the current improved to approximately 3.8 A and power is up to 79 W. Take in consideration that 79 W isn’t the maximum value of the panel. Some days we get a power up to 120 W but when we did the experiment it was cloudy and a little bit dusty.

D. DC-DC Converters
A maximum power point tracking system needs a converter that will control the voltage to obtain the maximum power. There are many types of converters, i.e. Boost, Buck, Buck-Boost, Cuk and SEPIC. In this project, we used buck type converter that steps down the voltage of the PV, Figure (09) shows DC converters in general.

Figure (10): DC Converters General Circuit [7]

Buck Converter:
The buck converter used for stepping down the input voltage. Figure.5 shows the basic circuit of a buck converter. The main component in the circuit is the switch, which can be a MOSFET, BJT or Thyristor. In this project, we used a MOSFET transistor as a switch. The output voltage depends on duty cycle ratio. Figure (11): Basic Circuit of a Buck [9] Converter

Duty Cycle:
The ratio between the input voltages to output voltage is called duty cycle. Duty cycle is important because it controls the switching pulse that will be injected to the MOSFET gate to control the output voltage.

L and C Selection:
In general, there are equations to select inductor and capacitor values. Here are the equations [8] :
C=18Lf2∆V Vout α:Duty Cycle f:Switching Frequancy
∆I:Maximum Output Ripple Current
∆V:Maximum Output Ripple Voltage
In this project, we may stick with the available values in the lab, and we can verify their performance experimentally.

Experimental Components:
For the buck converter, we used a variable resistance, inductors, capacitors, power diode and a switch that is a MOSFET (IRF 9130). The next pictures show the components of a buck DC-DC converter and one picture shows the connections:

Figure (12): (On the left) a MOSFET, (on the right) Power Diode

Figure (13): (On the left) a Function Generator, (on the right) an Oscilloscope

Figure (14): Updated Circuit of a Buck Type DC-DC Converter

We had to update our DC-DC circuit by adding two new resistors in series to do the voltage division rule. Feeding the gate a different voltage value than the one used to feed our source is essential for the circuit to work because if we want our circuit to work as a switch we must follow the MOSFETs rule which specifies that our source voltage value must be higher than the gate voltage value. If we want to shut down the circuit, we make the gate value higher than the source value and that’s how we fixed the problem we had in the DC-DC converter.

Figure (15): Connections of the DC-DC Buck Converter

Figure (16): Connection of a Buck Converter
The figures above are the connections of the original DC-DC converter. The connection of the updated DC-DC converter is shown below.

Figure (17): Connection of the Updated DC-DC converter E. Cassy Lab
After implementing the DC/DC converter we, the next step is designing MPPT controller that will take the values of the voltage and current from the panel arrays and apply the logarithms on the inputs according to the method applied to decide the output of the DC/DC converter depending on the duty cycle of the pulse signal that will trigger the MOSFET gate as mentioned before. There were two options for MPPT controller we can use it in the circuit, Microcontroller, and Cassy Lab. We prefer Cassy Lab over the Microcontroller for several reasons. First of all, all the equipments of the DC/DC converter are compatible with the available Cassy Lab equipments. Secondly, using Microcontroller will require delay in the project, because we need to order it and it takes at least one week to be delivered and programming of the Microcontroller will take time due to the high language required, unlike the easy writing formulas and functions in the Cassy Lab.

Figure (18): Example of some functions available in the Cassy Lab [10]

Many maximum power point tracking techniques for photovoltaic systems have been developed to maximize the produced solar energy. In general, there is a specific point on the V-I or V-P curve, named the Maximum Power Point (MPP), at which the PV system operates with maximum efficiency and produces the maximum output power. The location of the MPP is not known, but can be found, either through calculation models or by search algorithms. Maximum Power Point Tracking (MPPT) techniques are desired to preserve the PV array’s operating point at its MPP [12].These techniques are different than each other in many characteristics, involving simplicity, convergence speed, implementation, sensors required, cost and range of effectiveness .We will talk about the different MPPT techniques below in order:

A. Perturb and Observe
P&O is the most famous one from the MPPT algorithm method due to its simplicity and efficiency. P&O algorithm is grounded on the “hill-climbing” attitude that consists of moving the operation point of the PV array in the direction in which power rises. From Figure (19), it can be seen that incrementing (decrementing) the voltage increases (decreases) the power when operating on the left of the MPP and decreases (increases) the power when on the right of the MPP.

Figure (19): Characteristic PV array power curve. [11]

More on P & O method and its algorithm will be discussed in chapter 3.

B. Incremental Conductance
The incremental conductance method is based on the fact that the slope of the PV array power curve in figure (20) is zero at the MPP, positive on the left of the MPP, and negative on the right, as given by

Measurements of the instantaneous PV array voltage and current require two sensors. We can use a microcontroller control, which can easily keep track of previous values of voltage and current and from Figure (20). [13]

Figure (20): Incremental Conductance shown in [12].

C. Open-Circuit Voltage
This method is considered to be one of the best and easiest methods to track the MPPT. It is going to be discussed in details in chapter 4.

D. Short-Circuit Current
Fractional ISC comes from the statistic that under changing the weather conditions, IMPP is approximately linearly related to the ISC of the PV array as shown next.
Where k2is proportionality constant. Just like in VOC technique, k2 has to be determined according to the PV array in use. The constant k2 is generally found to be between 0.78 and 0.92 .Measuring ISC during operation is harder than measuring the open voltage circuit. We must use additional switch to the power converter to periodically short the PV array so that ISC can be measured using a current sensor. For all other applications we didn’t mention in the report, you can see Table III, covering the major characteristics of some MPPT techniques.

You can see in next table the different techniques of MPPT.
Table III. Major Characteristics of MPPT Techniques [13]

The perturbation and observation (P&O) technique for maximum power point tracking (MPPT) algorithm is very commonly used because of its ability to track maximum power point (MPP) under widely varying atmospheric condition.In Perturb and observe (P&O) method, the MPPT algorithm is based on the calculation of the PV power and the power change by sampling both the PV current and voltage. The tracker operates by periodically incrementing or decrementing the solar array voltage. In this method, the sign of the last perturbation and the sign of the last increment in the power are used to decide what the next perturbation should be. If there is an increment in the power, the perturbation should be kept in the same direction and if the power decreases, then the next perturbation should be in the opposite direction. Based on these facts, the algorithm is implemented. The process is repeated until the MPP is reached. Then the operating point oscillates around the MPP. This is summarized in the following table. [4]
Table IV: Summary of P&O algorithm [4] Perturbation | Change in Power | Next Perturbation | Positive | Positive | Positive | Positive | Negative | Negative | Negative | Positive | Negative | Negative | Negative | Positive |

The algorithm works when instantaneous PV array voltage and current are used, as long as sampling occurs only once in each switching cycle. The process is repeated periodically until the MPP is reached. The system then oscillates about the MPP. The oscillation can be minimized by reducing the perturbation step size. The figure below shows the flow chart of P&O technique. [5]

Figure (21): P&O Algorithm Chart [5]

For perturb and observe (P&O) we will measure the voltage and the current from the panel and calculate the power by using P= IxV.

Figure (22): CASSY Lab Connection [14]

After that we are going to use the logarithm of P&O As shown before by Cassy Lab using the condition below.

Figure (23): Condition of Perturb and Observe
Where the variable "delta" take the difference of the last two points of recording. And the program will understand it as true of false function, if it's satisfy the condition the result will be true=1, and if false=0.

Table V: Condition Results of Perturb and Observe n | Delta (P) | Delta( V) | Result | C | 1 | Positive | Positive | True | 1 | 2 | Positive | Negative | False | 0 | 3 | Negative | Positive | False | 0 | 4 | Negative | Negative | True | 1 |

In the next step, we are willing to program the duty cycle function that will increase if the previous condition is true, and decrease if the condition is false.

Figure (24): Duty Cycle Formula
We can see above the variable "n", that will increase one every one step recording, and the other part of the function that have cosine will be zero at true condition because Cos(90) = 0 , and when the condition is false the first part will be zero due to the C=0 and the second part will decrease the duty cycle. Then we plug the Duty Cycle (D) to the output of the function generator with Pulse function (Frequency = 200 Hz, Vp = 5V)

Figure (25): Function Generator Settings in CASSY Lab
* The logarithm of P&O depends on {if-then} Statement. Unfortunately, the Cassy Lab only understand the {if} statement without {then}. * The second problem of the Cassy Lab is you cannot use loops without resetting the result every step and this issue lead to resetting the duty cycle every single step. * Using "n" variable will increase in the duty cycle perfectly, but decreasing the duty cycle having a problem due to the increasing of variable "n" every step.

After taking automatic recording for one day, the duty cycle secedes 100% and reached 250% and this is because of the increasing of the variable "n".
Table VI: Duty Cycle Results

The second method we used in the project was the Open Voltage method, we decided to use a different method to do a comparison between the more than one method. The algorithm of the Open Voltage is much simpler than the Perturb and Observe algorithm where you only need the value of Voc. The equation that we use in this method is:
Where K is the constant of proportionality. Proportionality depends on the PV array and from experimentation we saw that the best K value is between 0.71 and 0.78 [5]. For this project we chose a constant value of K which is 0.76 (76%). This value is usually fixed and doesn’t vary much with the sudden changes in the environmental conditions [15]. After that you choose a value of the duty cycle that gives you 76% of your open voltage and start the system.

Figure (26): Block diagram of the voltage based MPPT [16]

The disadvantage of this method compared to the Perturb & Observe is that we must be careful when choosing a time interval to sample. If our sampling time interval which is called the sampling period is too long there will be a considerable power loss. Dr. Jawad Ahmad said: “This is because the output voltage of the PV module follows the unchanged reference during one sampling period. Once an MPP is tracked and a step in irradiance occurs between two consecutive samplings, then the new MPP is not calculated until the next sampling of the array voltage. Consequently, the method initially achieves an incorrect MPP instead of the current one” [16].

At first we connected our DC-DC circuit to a function generator, we didn’t connect any capacitor or inductor and just checked the output voltage from the Resistor. The duty cycle value was 76% and the input value was 15V and the output value was approximately 11.5V which is approximately 76% of the input value and it was square shaped like the Duty Cycle shape.

Figure (27): Function Generator for the Duty Cycle

Figure (28): Output Voltage using Oscilloscope

We still couldn’t see the exact values of the output voltage and how the value of the inductor decreased or increased the ripples so we took the duty cycle directly as a constant from the CASSY Lab output and connected it to our DC-DC converter circuit. Then we took the output directly from the resistor without the capacitor and inductor. The frequency was constant at 200 Hz. Our output voltage looked like:

Figure (29): Function Generator in CASSY Lab

Figure (30): Duty Cycle and Output Voltage without capacitor and inductor

As you can see from figure (27), the output voltage (black) was alternating exactly like the duty cycle (red).

After we connected the capacitor and inductor, and with different variables the output voltage looked like:

Figure (31): Duty Cycle and Output Voltage with capacitor and inductor The resistor value was 500 Ω and the inductor value that we chose was 0.06 H and the Capacitor value was 90 µF with a frequency of 200 Hz.

To see the effect of the frequency we changed the value of the frequency to 500 Hz with the same values of Resistor, inductor and capacitor.

Figure (32): Function Generator using CASSY Lab

Figure (33): Duty Cycle and Output Voltage with capacitor and inductor and 500Hz Frequency

The open voltage method follows the concept, we measure 76% of the open voltage method and the voltage we have it will give us the maximum power point at it duty cycle linear relation.

Figure (34): Open Voltage Formula
After this step, we change the duty cycle until the voltage after the buck converter will equal Vr, and we will get power higher than solar reading about 14% - 18%.

We connected the CASSY Lab to the updated DC-DC converter in figure (). We used the two panels in process and each of them had a specific job. The first panel was just used to calculate the value of the Open Circuit Voltage and directly gives us the VMAX. We used the other panel to turn on our DC-DC converter.

Figure (35): System with MPPT (blue) and without MPPT (red)

The day that we fixed the circuit was a cloudy and rainy day and as you can see from the graph the power that day was low but our Open Circuit Voltage method worked. As you can see, the output power from the MPPT system was higher than the Power of the system without MPPT and the difference between them was between 15% and 20%.

After 14 weeks of non-stop work, we finally implemented a full MPPT system and did two methods. We now know the importance of implementing a MPPT system to a PV panel and how the amount of power will increase due to the MPPT system.

We saw how temperature and irradiance variance during the 14 weeks due to natural weather conditions are affecting our power output. We saw the importance of a DC-DC converter which acts as an interface between the load and the solar module.

The main component of a DC-DC converter is the switching device which can be a MOSFET or a BJT. By using the right formulas, we saw how the value of a resistor or an inductor or a capacitor is extremely important for our MPPT system and we saw how a small change of any of these values will change the shape and value of our output.

After all the things we learned and did in this project, we faced some errors with the DC-DC converter and the MPPT controller by using the CASSY Lab Program in the P&O Method. The problem that we faced in the DC-DC converter was the MOSFET and its current rating. The main problem was that it couldn’t handle a high current and if it stays on high current for 30 seconds, our MOSFET will burn. The reliable solution for this problem is to work with an electronics expert to fix this problem.
The Future Work
The scope of this project was simply to create a working prototype of a MPPT system. This system successfully uses the simple P&O algorithm to reach the MPP. Reaching a stable, true MPP at steady state instead of oscillating around this point would improve the system's efficiency and increase reliability. Thus implementing the incremental conductance algorithm is a good choice in continuing this project. Another extension of this project would be to directly power the microcontroller and other circuits from the solar panel instead of from a power supply. Or to incorporate a power supply into the system that draws energy from the solar panel or an energy storage element that is in turn charged by the solar panel. This extension would allow the system to be deployed to remote locations.


[1] Wenham, Stuart R, Martin A Green, Muriel E Watt, Richard Corkish, and Alistair Sproul. Applied Photovoltaics. Third Edition. USA and Canada: Earthscan, 2011. 29-35. Print.

[2] Schwabe, U. "Performance measurement of amorphous and monocrystalline silicon PV modules in Eastern U.S. Energy production versus ambient and module temperature." . IEEE, 7 May 2009. Web. 24 Nov 2012.

[3] Zheng , Huiying. "Comparative study of maximum power point tracking control strategies for solar PV systems." . IEEE, 10 May 2012. Web. 24 Nov 2012.

[4] Morales, David. Maximum Power Point Tracking.MS thesis.Aalto University, 2010. Print.

[5] Harjai, Arjav. STUDY OF MAXIMUM POWER POINT.MS thesis.National Institute of Technology, 2007. Print

[6] Barchowsky, A.; Parvin, J.P.; Reed, G.F.; Korytowski, M.J.; Grainger, B.M.; , "A comparative study of MPPT methods for distributed photovoltaic generation," Innovative Smart Grid Technologies (ISGT), 2012 IEEE PES , vol., no., pp.1-7, 16-20 Jan. 2012

[7] Erickson, R. W. (n.d.). Dc-dc power converters. Informally published manuscript, Department of Electrical and Computer Engineering, University of Colorado, Boulder, CO 80309-0425. (Erickson)

[8] Mouhadjer, S., Chermitti, A., & Neçaibia, A. (2012). Easy way to electronic converter designers to design a buck converter application for photovoltaic systems. (15 ed., Vol. 50, pp. 28-32). (Mouhadjer, Chermitti & Neçaibia, 2012)

[9] Pandey, A. (2008). High-performance algorithms for drift avoidance and fast tracking in solar mppt system. (2 ed., Vol. 23, pp. 681-689). IEEE. (Pandey, 2008)

[10] Dr.Hund, Michael, and Timm Dr.Hanschke. "Cassy Lab Manual." . Web. 21 Sep 2007. <>.

[11] Ali, A.N.A.; Saied, M.H.; Mostafa, M.Z.; Abdel-Moneim, T.M.; , "A survey of maximum PPT techniques of PV systems," Energytech, 2012 IEEE , vol., no., pp.1-17, 29-31 May 2012

[12] Esram, T.; Chapman, P.L.; , "Comparison of Photovoltaic Array Maximum Power Point Tracking Techniques," Energy Conversion, IEEE Transactions on , vol.22, no.2, pp.439-449, June 2007

[13] Faranda, R.; Leva, S.; Maugeri, V.; , "MPPT techniques for PV Systems: Energetic and cost comparison," Power and Energy Society General Meeting - Conversion and Delivery of Electrical Energy in the 21st Century, 2008 IEEE , vol., no., pp.1-6, 20-24 July 2008

[14] Takun, Pongsakor, Somyot Kaitwanidvilaichke, and Chaiyan Jettanasenidvilaichke. "Maximum Power Point Tracking using Fuzzy Logic Control for Photovoltaic Systems.”. N.p., 16 2011.

[15] A.Chaudhari, Vikrant. Automatic Peak Power Tracker using dSPACER.MS thesis

[16] Ahmad, J.; , "A fractional open circuit voltage based maximum power point tracker for photovoltaic arrays," Software Technology and Engineering (ICSTE), 2010 2nd International Conference on , vol.1, no., pp.V1-247-V1-250, 3-5 Oct. 2010

Similar Documents

Free Essay

Países Árabes: Alternativas Para El Intercambio Comercial de Latinoamérica

...financiera. Por otra, los países emergentes pueden tomar ventaja de lo que ello representa y generar cambios que faciliten el intercambio comercial, la atracción, y el establecimiento de nuevas empresas. La forma de comenzar a prospectar nuevas oportunidades de negocio comienzan investigando qué tipo de productos pueden estar demandando otros mercados emergentes. De los 22 países que conforman la Liga Árabe (Araba Saudita, Argelia, Bahrein, Emiratos Árabes Unidos, Egipto, Irak, Jordania, Kuwait, Líbano, Libia, Marruecos, Mauritania, Omán, Qatar, Siria, Sudán, Somalia, Islas Comoras, Palestina, Túnez, Yemen y Yibuti), son seis algunos de los más prometedores para Latinoamérica. Los países que integran el Consejo de Cooperación del Golfo (Arabia Saudita, Kuwait, Bahrein, Qatar, EAU y Omán) han basado su economía en la exportación de petróleo durante más de 30 años, lo que les ha permitido el desarrollo del sector privado en diferentes industrias, demandando una gran variedad de productos del exterior para satisfacer el consumo interno. Estos seis países cuentan con una población de alrededor de 38.9 millones de habitantes, su PIB suma más de 1,261 billones de dólares, y tres de ellos se encuentran en las mejores posiciones del mundo en cuanto a PIB per cápita, ocupando Qatar el 1er lugar, EAU el 9º y Kuwait el 10º. A pesar de contar con las más grandes reservas de petróleo y gas en el mundo, los países del CCG cuentan con limitados recursos naturales, lo cual los ha......

Words: 588 - Pages: 3

Premium Essay

English Teacher

...CV Name: Farah Ali Elbalula Abd Elqadir Target Job Title: English Teacher, Translator, HR Coordinator Target Job Location: UAE; Saudi Arabia; Qatar; Kuwait, Oman Career Objective: Highly motivated teacher and seeking new challenges in which effectively utilizes my professional Experience. Looking to join a progressive organization School that has the need for a proactive person to develop the communicating standards, achievements and area of growth to students ;-Defining learning expectations and providing timely evaluative feedback on students performance ;Motivating and engaging students in meaning learning and growth ; - Implementing a variety of strategies to address students , learning strengths and area of weakness ,learning styles and various intelligences as well as learning how to learn . To obtain a position in a team role using teaching administrative programming and management skills. I have first hand teaching construction and building strong team environments and developing open communications. Strong acumen including teaching, translating, counseling, coordinating and administrating. Employment Type: Employee Employment Status: Full time Target Monthly......

Words: 477 - Pages: 2

Free Essay

Management 5360 Saudi Arabia

...Doing Business in Saudi Arabia 1) Prepare a short description of the most striking cultural characteristics that may affect business interaction in this country. Doing business in Saudi Arabia requires significant research if I expect to be successful. There are many cultural differences that must be taken in consideration prior to and during business interactions. The Saudi Arabian culture, its shared values and norms, is distinctly different from our western culture. Saudi Arabian social structure emphasizes a group rather than individualism. Saudi’s are more likely to identify themselves as a part of something (e.g., “I am from Exxon Mobil”) rather than identifying their individual role (e.g., “I am an engineer”). It will also be important to understand the social stratification within Saudi Arabia. Having a working knowledge of the significance of the tribal affiliations as well as the varied groups of which someone can be a part will help me to understand which individuals I need to approach and build relationships with in order to be successful in the region. It will also be incredibly important for me to understand the role of religion, specifically Islam, in the region and how it affects work ethic, business decisions, and simple logistics throughout the day. As Americans, we are focused on our work and we allow very little to get in the way of our accomplishments. Saudi’s are very different. Work is secondary to many things, most notably,......

Words: 1696 - Pages: 7

Premium Essay


...NAME: EZIMAH CHIDINMA MATRIC NO: 10/SMS01/020 QUESTION: DISCUSS OPEC AS A COLLUSION MARKET STRUCTURE OPEC AS A COLLUSION MARKET STRUCTRE Collusion is a characteristic trait of oligopolistic industries. Intense competition and interdependent decision making encourages oligopolistic firms to cooperate. One way to lessen the competition among an oligopolistic rival is to join forces through collusion. In general, collusion among oligopolistic firms means that two or more firms decide to act like a monopoly rather than maximizing profit for each individual firm, the firms maximize total industry profit just as if a monopoly controlled the industry. Collusion can take one of two forms: explicit collusion and implicit collusion. * Explicit collusion: it is also called overt collusion. This occurs when two or more firms in the same industry formally agree to control the market. Admittedly, because collusion in the United States and most industrialized countries is illegal, such a formal agreement is likely to be highly secret and unlikely to be documented in any way. It might involve nothing more than a casual lunch among company presidents or company decision makers skulking around back alleys in the dead of the night discussing price changes. * Implicit collusion: also termed tacit collusion. This occurs when two or more firms in the same industry informally agree to control the market, often through nothing more than interdependent actions. A prime example of implicit......

Words: 1340 - Pages: 6

Free Essay

Preparing or Hajj

...IN THE NAME OF ALLAH MOST GRACIOUS, MOST MERCIFUL    Preparing for Hajj & ‘Umrah  (Culled from Part 1  Every year, millions of Muslims make the journey of their lifetime. They come from all over the world for the sole purpose of fulfilling one of Allah’s greatest commandments to mankind – the Hajj. Abu Hurairah deed?’ He narrated that “The Prophet was asked, ‘Which is the best ).’ He was then asked, said: ‘to believe in Allah and His Messenger ( ‘Which is the next (good deed)?’ He said: ‘To participate in Jihad in Allah’s cause.’ He said: ‘To perform an accepted Hajj.” [Al- was then asked, ‘Which is the next?’ He Bukhari] For over 1400 years, believers have been making Hajj to the House of Allah in Makka. It is an obligation for each and every Muslim to perform Hajj at least once in his/her lifetime if he is physically and financially able. Pre­Hajj preparations  Due to the importance of Hajj, preparations for it should not be taken lightly. Besides planning the actually logistics of the trip, the Muslim needs to prepare Islamically, physically, mentally, and financially for this great act of worship. Islamically, one of the most important preparations for this journey is acquiring the necessary knowledge for performing the rituals of Hajj and ‘Umrah correctly and in accordance to the Sunnah of the Prophet . This means studying and learning about Islam, acquiring a high degree of Imaan (faith) in order to deal with the emotional and......

Words: 1919 - Pages: 8

Premium Essay


...women's role in workplace. We find Arab women not only behind the curtains of their houses but also as entrepreneurs, designers, in the field of science, IT, commerce, media, cinema, law and even in the army. Improved health care, education, jobs, facilities have made Arab women independent and self confident. Interlaq project in UAE encourages women to take up jobs in government departments. Most of the Arab nations have recognized and appreciated women although there are places even now where they do not enjoy full freedom. Even in leadership , women are at par with men. The Arab parliaments approved constitutional amendments to give women full potential rights, starting from Syria in 1949, Lebanon in 1952 to Kuwait in 2005 and Saudi Arabia in 2015. Massouma al-Mubarak was the first female cabinet minister of Kuwait. Women's radicalism against dictatorship and cultural norms have long and deep roots. The arabic word for revolution, "thawra", "huriya" for freedom and "intifada" for uprising all has a female gender. Arab women have overcome the tears of past, showed their capabilities...

Words: 338 - Pages: 2

Premium Essay

P1- Btec Unit 1

...G2 * Emaar (Profit orientated business) Emaar is a real-estate company which is based in the United Arab Emirates. It is currently the Persian Gulf region's largest land and real estate developer. With over 60 companies, Emaar's activities include property investment and development, property management services, education, healthcare, retail and hospitality sectors, as well as investing in financial service providers. Type of ownership: Public Joint Stock Company (public limited) Liability: Limited liability Size: Emaar is extending its expertise in developing master-planned communities internationally, and has a significant presence in several key global markets with established operations in the United Arab Emirates, Saudi Arabia, Syria, Jordan, Lebanon, Egypt, Morocco, India, Pakistan, Turkey, USA and Canada. It employs over 10,000 people and has over 60 companies. Revenue: $3.307 billion (2010) Sector: Secondary sector Purpose: to transform Emaar into a one-stop, global solution provider for lifestyle, including homes, work, play, leisure, retail, health, education, finance, industry and more. * Dubai Autism Centre (Nonprofit organization) Since November 18th2001 The Dubai Autism Center began the creation of its various services targeted towards encouraging a better understanding of Autism and providing specialist services for people with Autism and those who care for them. It is a center of excellence having highly trained professionals to......

Words: 295 - Pages: 2

Premium Essay

Pestle Analysis of Italy

...Western nations and then put back into those same nations' banks. For example if Libya were to receive money from the U.S. for oil and then put the money into a U.S. bank, that deposited money is referred to as petrodollars. We use the International Monetary Fund’s definition of oil exporters—those countries that currently derive the bulk of their export revenues from sales of fuel. Norway has been added because last year the country derived roughly 53 percent of export revenues from oil. Origin of petrodollar phenomenon: The Organization of the Petroleum Exporting Countries (OPEC) was founded in Baghdad, Iraq, with the signing of an agreement in September 1960 by five countries namely Islamic Republic of Iran, Iraq, Kuwait, Saudi Arabia and Venezuela. They were to become the Founder Members of the Organization. This cartel controlled the export of oil to majority of the countries of the world. In 1971, USA printed & spent far more paper money than it could cover by gold. By 1973, the French demanded redemption of its paper dollar holdings in gold. However USA rejected it since it did not have enough gold reserves to back up the...

Words: 1509 - Pages: 7

Premium Essay

Managers Job in Context

...skill of individual managers, who practice what they preach are what counts, that is why hiring the right manager is essential in supervising and managing the overall performance of staff in their department (Robbins, 2001). ‘People in the organisation are your most important asset’ is an incorrect statement; because I believe the right people are the organisation’s most important asset. Therefore, companies should hire based on the correct individual’s attitude and behaviour for the company, then train and develop those who deem to have potential. 2.0 Organizational Background – Al-Rajhi Bank Al-Rajhi Bank is the world’s largest Islamic bank and is one of the largest joint stock companies in Saudi Arabia. Al-Rajhi Bank is a huge contributor in the investments of Saudi Arabia business world. The bank offers a wide range of banking and investment services all within framework...

Words: 325 - Pages: 2

Premium Essay

Four Types of Research

...The responsibility of law enforcement is to protect and serve the community as well as make sure the law is obeyed by all citizens. In many instances, civil order is implemented by specialized units. The objective of this assignment is to discuss how the United States handles issues relating to civil order control. In addition, this paper will compare and contrast procedures utilized by other countries. Functions of civil order in the United States are outlined by enforcing the laws of the land, protecting the civil rights of citizens and protect federal property (Feaver, Hikotani, & Narine, 2005). By enforcing the laws, the United States assume the responsibility keeping order in the world. Keeping order assist in the protection of the civil rights of citizens and federal property. Examples of organizations created to implement civil order in the United States are the U.S Department of Homeland Securities and the National Guard. The purpose of the U.S. Department of Homeland Securities is to protect the country the various threats. In response to the 9/11 attacks on U.S. soil, this department was created to respond to terrorist attack, human attacks and natural disasters. Some of the department jobs include aviation, border security, emergency response, cybersecurity and chemical inspections (Homeland Security, 2011). It main is to provide safety for the American people on American soil. The purpose of the National Guard is to supply defense for the United......

Words: 635 - Pages: 3

Premium Essay

Business Proposal

...Executive Summary The purpose of this business proposal is to gain investor interest in capitalizing on Saudi Arabia’s blooming construction industry. Due to the lack of demand in the US, Future Growth Inc. has cut down on manufacturing construction and forestry machinery. The emerging demand for heavy machinery in the Middle East motivates FGI to increase barriers to entry in the construction industry by using pricing and nonpricing strategies. FGI needs financial support in the endeavor to enter the global economy with significant advertisement and appropriate prices.   Week 4 Business Proposal Future Growth Inc. (FGI) has the ability and determination to succeed. Since 1951 FGI has built, sold, and financed its own brand of construction and forestry equipment with increased profits year after year. Due to the falling American economy, profits declined 30 percent, one-third of FGI’s workforce was laid off, and the domino effect of reduced new-home sales has hindered the entire construction industry. Despite the economic downturn, hospitals and nursing homes still have a demand for new buildings in the United States (University of Phoenix). Future Growth Inc. manufactures heavy construction equipment used for the development of residential and nonresidential buildings, energy and manufacturing plants, water lines, roads, and bridges. Such heavy equipment consists of bulldozers, large cranes, mixers, pavers, and off-highway trucks. Being experienced in the......

Words: 1465 - Pages: 6

Premium Essay

Admission Essay develop and learn sign language through which we all communicate with him now. I was too young at the time, but my older siblings told me of the stories when during the civil war in Lebanon, my mother would risk it all to go see him and bring him home for Christmas as his school was on the other side of the line separating Beirut into two warring camps at the time. Around the mid-eighties, the war had become much worse, and Palestinians were being targeted in Lebanon, at which point my parents decided to bring my eldest brother back to Saudi Arabia. By the time the war had ended in Lebanon, it was too late for my brother to go back to school, as he was too old. In Saudi Arabia, my parents tried to get my brother enrolled in several special schools in the Middle East, but there were always obstacles. As Palestinians we could not travel to Jordan or Egypt where similar schools were available. To complicate matters, Saudi Arabia had little to offer in terms of schools suitable for my eldest brother. Since my mother’s passing, my eldest brother has been living with my older sister in...

Words: 679 - Pages: 3

Premium Essay


...The Saudi Arabian Oil Company (Saudi Aramco) is the world's leading oil producing and exporting company. It is a fully-integrated, global petroleum enterprise that manages the world's largest oil reserves – about 260 billion barrels – and also manages the world's fourth largest natural gas reserves. Saudi Aramco is a fully integrated global petroleum enterprise headquartered in Dhahran, Saudi Arabia, participating in exploration & producing, refining, distribution, shipping, and marketing. With around 54,000 employees globally, representing 56 nationalities, the company is 100% owned by Saudi Arabian Government. Saudi Aramco has affiliates, joint ventures and subsidiary offices in China, Egypt, Greece, Japan, Netherlands, Philippines, Republic of Korea, Singapore, United Arab Emirates and the United States.Saudi Petroleum Overseas, Ltd is based in London and provides marketing and ocean transport support services. A subsidiary of Saudi Aramco owns a fleet of oil tankers to transport crude oil to key customers. Saudi Aramco, through subsidiaries, also invests in refineries and distribution networks around the globe. In addition to its headquarters in Saudi Arabia's Eastern Province city of Dhahran, Saudi Aramco has affiliates, joint ventures and subsidiary offices in China, Egypt, Japan, the Netherlands, Philippines, Republic of Korea, Singapore, United Arab Emirates, United Kingdom and the United States. In 2008, Saudi Aramco is celebrating its 75th......

Words: 289 - Pages: 2

Premium Essay

Communication and the Gloabl Community

...COMMUNICATION AND THE GLOBAL COMMUNITY COLORADO TECHNICAL UNIVERSITY ONLINE JAMAULA T. SYKES MGM316-1401B-03 PROFESSOR R. PLANTE FEBRUARY 26, 2014 COMMUNICATION AND THE GLOBAL COMMUNITY One of the most important factors to remember it that not all countries have the same believes and cultures. This would be the case for expanding business to the United Arab Emirates, Israel, Mexico, and China. In order to whip crews in shape to effectively function in these countries, they must endure long hours, intense training, communication woes, and preparing for a life changing experience. * What would your students need to know in regards to high- and low-context language, language diversity, interaction, nonverbal communication, and so forth? Employees must realize that in terms of high/low context communication, there is little to no nonverbal communication. This can classified as disrespect in some countries. With high context communication, this is most often used in long term, established relationships with clients. Relationships are built slowly and are dependent upon trust and stability. Low context communication is more public and external. This is used for shorter communication and usually rule oriented. In low text, relationships are come and go. Beginning just as a quick as it ends. * What are some conversation taboos that they should be aware of? Some of the conversation taboos that employees should be aware of includes conversations tied to......

Words: 540 - Pages: 3

Free Essay

Yemen Oil Conflit

...published a story about an oil conflict rising between Saudi Arabia and Yemen. The Egyptian newspaper, al-Masry al-Yom, quoted in the story, refers to the conflict as the “Yemen - Saudi Arabia new Oil conflict” (Yemen Post) implying preexisting disputes between the two countries regarding the extraction of natural resources. Until 2012, Yemen's officials embraced its country's world-wide image as the poorest country in the Arabian Peninsula with depleted natural resources. However, starting with the resignation of then president, Ali Abdullah Saleh, the discovery of large petrol deposits in earth pockets worth up to several billion dollars were made public. Yemen's close neighbor, Saudi Arabia, the superpower of oil exports in the region, is becoming more uneasy, especially after rough estimates predicting that soon Yemen could be “home to much of the world's oil and gas resources, maybe just as much as Saudi Arabia itself”(Yemen Post). Experts from Yemen Post are also speculating that the newly discovered fortune could be the answer to Yemen's current unemployment rate, poverty, illiteracy and other problems. With vast natural resources, arable lands, key geographical location and military potential, Yemen could soon challenge the superpower of Saudi Arabia in the region. The disputes over borders between the two countries dating back to the Saudi-Yemen war in 1934 could soon resurface especially with Saudi Arabia resuming its construction of the fence along the Yemen......

Words: 2726 - Pages: 11