CONTROL OF GRID CONNECTED SOLAR PHOTOVOL

CONTROL OF GRID CONNECTED SOLAR PHOTOVOLTAIC SYSTEM A DISSERTATION Submitted in partial fulfillment of the requirements for the award of the degree of MASTER OF TECHNOLOGY in ALTERNATE HYDRO ENERGY SYSTEMS By ZAMEER AHMAD ALTERNATE HYDRO ENERGY CENTRE INDIAN INSTITUTE OF TECHNOLOGY ROORKEE ROORKEE ― 247667 (INDIA) JUNE, 2013 CANDIDATE’S DECLARATION I hereby declare that the work which is being presented in this dissertation report entitled “Control of Grid Connected Solar Photovoltaic System” submitted in partial fulfilment of the requirements for the award of the degree of Master of Technology with specialization in Alternate Hydro Energy Systems, submitted in Alternate Hydro Energy Centre, Indian Institute of Technology Roorkee is an authentic record of my own work carried out during a period from July 2012 to June 2013 under the supervision of DR S.N.Singh, senior scientific officer, Alternate Hydro Energy Centre, Indian Institute of Technology Roorkee The matter embodied in this dissertation report has not been submitted by me for the award of any other degree or diploma Date: 10 June, 2013 Place: Roorkee (Zameer Ahmad) This is to certify that the above statement made by the candidate is correct to the best of my knowledge (S.N.Singh) Senior scientific officer, Alternate Hydro Energy Centre, Indian Institute of Technology Roorkee, Roorkee-247667 (Uttarakhand) ACKNOWLEDGEMENT I would like to express my deep sense of gratitude to my guide DR S.N.Singh, senior scientific officer, Alternate Hydro Energy Centre, Indian Institute of Technology Roorkee, for providing me all the necessary guidance and inspirational support throughout this dissertation work I can never forget his caring words and support in the difficult times They have displayed unique tolerance and understanding at every step of progress, without which this dissertation work would not has been in the present shape I wish to express my profound gratitude to Dr R P Saini, Head, Alternate Hydro Energy centre, Indian Institute of Technology Roorkee for providing all the facilities, which would have made it possible for me to complete this dissertation work I also owe a great deal of appreciation to all faculty members and staff of Alternate Hydro Energy Centre, Indian Institute of Technology Roorkee who have helped me directly or indirectly for the completion of this dissertation I would also like to thank all my friends for their help and encouragement at the hour of need As a final personal note, I am most grateful to the Almighty for showering blessings on me and my family members who are inspirational to me in their understanding, patience and constant encouragement Date: 10 June, 2013 (Zameer Ahmad) ABSTRACT In modern contest the world is moving from conventional energy sources to the renewable one It is due to its greater abundance and environment friendly characteristics Solar energy is one of the most promising renewable resources that can be used to produce electric energy through photovoltaic process A significant advantage of photovoltaic (PV) systems is the use of the abundant and free energy from the sun Power electronic devices used as interface between renewable power and its user It makes the power generated by renewable sources suitable for utilization Solar power contribution in power generation has been increasing very fast and cost of power generated by solar photovoltaic is falling rapidly Solar photovoltaic cell converts solar energy directly into dc power Power is mostly transmitted and utilized in ac form because of advantages associated with it To convert the dc power into ac, a highly efficient converter is required for optimum utilization of energy Power electronic devices can be used for this purpose, because they are highly efficient, light weight, small size, very fast and most reliable Power electronic devices used as a switch Power electronics devices required control signal for its operation These signals may require continuously or at the time of switching There are many controllers which generate control signal and has its own advantages and disadvantages The characteristic of solar photovoltaic cell is such that it has a point on curve which corresponds to maximum power So it becomes necessary to design a controller which not only convert dc power of solar to ac but convert peak power This work demonstrates a new method that can be used for transferring solar energy into the grid This consists of designing of line commutated inverter and microcontroller based control circuit The microcontroller has been used to design the control circuit because of its greater reliability, flexibility and versality Besides the delay angle can be controlled according to requirement by just changing the program not the hardware setup CONTENTS TITLE Page No Candidate’s Declaration i Acknowledgement ii Abstract iii Contents iv List of Figures vii List of Tables ix List of abbreviations x List of symbols xi INTRODUCTION 1.1 GENERAL 1.2 ENERGY CLASSIFICATION 1.2.1 Non-Renewable energy resources 1.2.2 Renewable energy resources CHAPTER 1.2.2.1 Status of renewable energy in India 1.3 SOLAR ENERGY 1.3.1 Solar photovoltaic system 1.3.1.1 Photovoltaic energy conversion 1.3.1.2 Photovoltaic technology 1.3.1.3 Grid-Connected PV Systems 8051 MICROCONTROLLER 1.4.1 Basic architecture of 8051 microcontroller 1.4.2 Features of 8051 1.4.3 Timers of 8051 POWER ELECTRONICS 1.5.1 Power electronic devices 1.5.2 Power converter topologies 1.6 OBJECTIVES OF DISSERTATION 10 1.7 ORGANIZATION OF DISSERTATION REPORT 10 1.4 1.5 LITERATURE REVIEW 11 2.1 CONTROL OF GRID CONNECTED PV SYSTEMS 11 2.2 PEAK POWER POINT TRACKING 12 METHODOLOGY AND FLOWCHARTS 14 METHODOLOGY 14 3.1.1 Flowchart of the proposed method 15 SYNCHRONIZATION 16 3.2.2 Synchronization flowchart 16 3.2.3 Program of Synchronization 17 CONTROL PULSE OR TRIGGERING PULSE 18 3.3.1 Triggering Pulse Flowchart 18 3.3.2 Program For Triggering Pulse 19 INTERFACING 20 3.4.1 Interfacing program of ADC with 8255 20 SOFTWARE MODEL OF SPV CELL 21 4.1 MATHEMATICAL MODELING 21 4.2 MATLAB SIMULINK MODEL 23 4.2.1 PV module characteristics 23 MAXIMUM POWER POINT TRACKING 25 EXPERIMENTAL SETUP 32 5.1 INTRODUCTION 32 5.2 COMPLETE CIRCUIT DIAGRAM 33 5.3 DEVELOPED MODEL 35 5.4 DESCRIPTION OF CONTROL UNIT COMPONENTS 36 5.4.1 8051 advanced microprocessor development kit 36 5.4.2 Zero crossing detector 37 5.4.4 Analog to digital converter 37 5.4.5 Isolation for control pulse 38 POWER UNIT CIRCUIT DESCRIPTION 40 5.5.1 Single phase fully controlled converter 40 RESULTS AND DISCUSSION 41 6.1 ZERO CROSSING DETECTOR 41 6.2 DELAY TIME CALCULATION 42 CHAPTER CHAPTER 3.1 3.2 3.3 3.4 CHAPTER 4.3 CHAPTER 5.5 CHAPTER 6 6.3 SYNCHRONIZATION 43 6.4 TRINGGERING PULSES 44 6.5 OUTPUT VOLTAGE WAVEFORM 47 CONCLUSIONS AND FUTURE SCOPE 49 7.1 CONCLUSIONS 49 7.2 FUTURE SCOPE OF THE WORK 50 CHAPTER LIST OF PUBLICATIONS 51 REFERENCES 52 LIST OF FIGURES Figure No Description Page No 1.1 Renewable energy resources 1.2 Photovoltaic energy conversions 1.3 Technology used for PV cells 1.4 Main components of grid-connected photovoltaic systems 1.5 Basic architecture of 8051 1.6 Timer registers 1.7 Basic power electronics system 1.8 Power semiconductor devices 1.9 Ratings of Power semiconductor devices 3.1 Single Phase Fully Controlled Converter with RLE load 14 3.2 Flow chart of the proposed method 15 3.3 Flowchart of the synchronization 16 3.4 Flowchart of Triggering pulses 18 4.1 Electrical equivalent circuit of PV cell 21 4.2 Model of solar photovoltaic module 23 4.3 Characteristic curve 24 4.4-4.16 I-V, P-V and dp/dv-V characteristics curves at different solar 26 insolation and different temperatures 4.17 Voc vs Vmpp 30 4.18 Actual Pmax and Pmax tracked 31 4.19 Power loss in fixed Vmpp and actually tracking of Vmpp 31 5.1 Main circuit diagram 33 5.2 Photograph of developed model 35 5.3 Photograph of solar module used 35 5.4 8051 microcontroller kit 36 5.5 Zero crossing detector (a) circuit diagram, (b) photograph 37 5.6 Circuit diagram of ADC (a) circuit diagram, (b) photograph 38 5.7 Driver and Buffer circuit (a) circuit diagram, (b) photograph 39 5.8 Single Phase Fully Controlled Converter with RLE load 40 6.1 Output of zero crossing detector 41 6.2 Output of Zero Crossing Detector as square wave 41 6.3 Synchronized pulse 43 6.4 Triggering pulse with 5ms delay 44 6.5 Triggering pulse with ms delay 45 6.6 Triggering pulse with ms delay 45 6.7 Triggering pulse with ms delay 46 6.8 Triggering pulse with ms delay 46 6.9 Output Voltages and Load Current Waveform for different 47 Triggering angles 6.10 Output voltage waveform and source current waveforms 48 LIST OF TABLES Table No Description Page No 1.1 Status of renewable energy in India 1.2 Conversion efficiency of cell 1.3 Four basic types of converters 4.1 Parameters of ELDORA40 Solar Module 23 4.2 Major Characteristics of MPPT Tequenique 25 10 5.5 POWER UNIT CIRCUIT DESCRIPTION The power circuit, which consist thyristors, is a high voltage circuit (normally of the order of several hundreds of volts) Power unit comprises of the following components: Line commutated inverter and Solar photovoltaic 5.5.1 Single Phase Fully Controlled Converter Single Phase Fully Controlled Converter with RLE load is shown in Figure 5.8 SNUBBER CIRCUIT (a) SCR (b) Fig 5.8: Single Phase Fully Controlled Converter with RLE load (a) circuit diagram, (b) photograph 52 CHAPTER RESULTS AND DISCUSSION 6.1 ZERO CROSSING DETECTOR The output of zero crossing detector is given in figure 6.1 output of zero crossing detector is not only detecting the zero crossing of supply but also produce a high pulse of V corresponding to the positive cycle of the supply as given in figure 6.2 Negative pulse is blocked by diode Fig.6.1: Output of zero crossing detector Fig.6.2: Output of Zero Crossing Detector as square wave 53 6.2 DELAY TIME CALCULATION Timer clock frequency FC = 1/12 of the crystal frequency FXT; Crystal frequency=11.0592 MHz Fc= 11.0592 MHz / 12 = 921.6 kHz Time period Tc = 1/921.6 kHz = 1.085us Delay time = number of counts × 1.085us Calculation of the values to be loaded into the TL and TH registers: (i) Required delay is divided by 1.085 us (ii) Value obtained in (i) is subtracted from 65536 (iii)Value obtained in (ii) is converted into hex as ABCD (iv) Load TL = AB and TH = CD 54 6.3 SYNCHRONIZATION Control pulse generated by the microcontroller must be synchronized with supply If control pulse is not synchronized with supply frequency the power circuit triggered wrongly It is clear from the output shown in figure 6.3 that pulse generated by microcontroller is synchronized with supply frequency (a) OUPUT OF ZCD CONTROL PULSE (b) Fig.6.3: synchronized pulse (a) synchronized with +ve cycle (b) synchronized with ve cycle 55 6.4 TRIGGERING PULSES The topology of inverter used in the proposed work is fully controlled full wave inverter This topology of inverter has bridge of four thyristers Four triggering pulses are required to trigger the thyristors of this topology The thyristers T1 and T2 are triggered simultaneously with same type of gate pulse G1 and G2 and other two thyristers T3 and T4 required gate pulse G3 and G4 complementary to the gate pulses of thyristers T1 and T2 The control or triggering pulses generated experimentally various delay time is being depicted below The converter circuit work as an inverter only when thyristers are trigger after 90 degree and there is an inductive load connected to circuit Triggering pulse of any delay can be generated by microcontroller by feeding suitable value to timer just by changing the program without any change in hardware The waveform record of control pluses generated by controller for various time delays is given in Fig 6.4, 6.5, 6.6, 6.7 and 6.8 (a) (b) Fig.6.4: control pulse with 5ms delay (a) generated by controller for G1 and G2 (b) generated by controller for G3 and G4 56 (a) (b) Fig.6.5: control pulse with ms delay (a) generated by controller for G1 and G2 (b) generated by controller for G3 and G4 (a) (b) Fig.6.6: control pulse with ms delay (a) generated by controller for G1 and G2 (b) generated by controller for G3 and G4 57 (a) (b) Fig.6.7: control pulse with ms delay (a) generated by controller for G1 and G2 (b) generated by controller for G3 and G4 (a) (b) Fig.6.8: control pulse with ms delay (a) generated by controller for G1 and G2 (b) generated by controller for G3 and G4 58 6.5 OUTPUT VOLTAGE WAVEFORM The output wave forms obtained experimentally are given in figure 6.9 and 6.10 It is clear from the negative value of output voltage wave form that power is being transferred to grid from the solar photovoltaic panel connected to the load side OUTPUT VOLTAGE LOAD CURRENT Fig 6.9: Output Voltages and Load Current Waveform for different Triggering angles 59 SOURCE CURRENT VOLTAGE ACROSS LOAD Fig.6.10: Output voltage waveform and source current waveforms 60 CHAPTER-7 CONCLUSIONS AND FUTURE SCOPE 7.1 CONCLUSIONS The use of microcontroller based control circuit provides us large number of advantages It reduces size and cost of controller significantly The efficient control of delay angle is the main advantage Besides this it provide more versality and greater scope for further improvement just by changing the program but not hardware configuration This work is carried out by breaking it into several steps for its smooth and successful completion The first stage consisted of generating control pulse which corresponds to peak power of solar photovoltaic module The first stage, a synchronized control pulse for an ac to dc converter/ inverter for the full wave was generated After getting satisfactory results then delay program was changed to generate a control pulse whose delay angle was adjusted beyond 90 degree to operate converter in inversion mode, at this condition the converter supplies the energy from solar photovoltaic cell to grid The developed relation between open circuit voltage and voltage corresponding to maximum power point is unique for a module Peak power tracked by this method is very accurate The performance of controller is found satisfactory In general switching control mode as well as specific application mode for solar photovoltaic grid interactive inverter The wave form records shows accuracy of delay of control pulse and also show the satisfactory performance of whole setup 61 7.2 FUTURE SCOPE OF THE WORK Following study can be carried out in future: Following analysis can be carried out before field implementation: (i) Total harmonic distortion of grid power quality (ii) Power inversion analysis (iii) Developed method for tracking of Pmax implement experimentally (iv) Cost analysis Programming microcontroller for the grid interactive in all weather condition for three phase system The developed relation between Voc and Vmpp should be derived by experimental setup Controller can be used for the control of FACTS devices by little modification This controller can be applied in HVDC transmission 62 LIST OF PUBLICATIONS Zameer Ahmad and S.N Singh, “ Modeling and Control of Grid Connected Photovoltaic System-A Review” International Journal of Emerging Technology and Advanced Engineering (ISSN 2250–2459, ISO 9001:2008 Certified Journal, Volume 3, Issue 3, March 2013) Zameer Ahmad and S.N Singh, “Extraction of the Internal Parameters of Solar photovoltaic Module by developing Matlab / Simulink Based Model” International Journal of Applied Engineering Research, ISSN 0973-4562 Vol.7 No.11 (2012) Zameer Ahmad and S.N Singh, “Microcontroller Based Advanced Triggering Circuit for Converters/Inverters” (Submitted) 63 REFERENCES [1] Ned Mohan, “Power Electronics, Applications and Design,” John Wiley & Sons, 3rd Edition, 2002 [2] Asghar, M.S “power electronics,” Delhi, Prentice H India, 2004 [3] World Energy Assessment –Energy & the Challenge of Sustainability UNDP, 2000 [4] www.mnre.gov.in/mission-and-vision-2/achievements, 10 may, 2013 [5] National Renewable Energy Laboratory http://nrel.com [6] http://www.maproyalty.com/solar.html, 10, Feb, 2013 [7] www.bca.gov.sg/publications/ /handbook_for_solar_pv_systems.pdf 16 may, 2013 [8] http://nptel.iitm.ac.in/video.php?subjectId=108105058, may, 2013 [9] Walid Omran, “Performance Analysis of Grid-Connected Photovoltaic Systems” Philosophy of doctorate Thesis, Electrical and Computer Engineering, Ontario, Canada, 2010 [10] Mazidi, Muhammad Ali & Mazidi, Janice Gillispie, “the 8051 microcontroller and embedded system”, Pearson education, 7th Indian reprint, 2004 [11] Ayala, j Kenneth, “the 8051 Microcontroller Architecture Programming and Applications,” 2nd Edition [12] www.viit.ac.in/8051_Micro_controller.pdf, 20 may, 2013-05-22 [13] M.H.Rashid, “Power Electronics Circuits, Devices and Application,” Delhi, Prentice H India, 3rd Edition, 2004 [14] http://nptel.iitm.ac.in/courses/Webcoursecontents/IIT%20Kharagpur/Power% 20Electronics/New_index1.html.10 May, 2013 [15] www.ece.colorado.edu/~ecen5797/ ECEN4797/5797 Intro to Power Electronics.25/11/12 13, March, 2013 [16] http://nptel.iitm.ac.in/courses/108101038/ 12, March, 2013 [17] Carrasco, Leopoldo, Bialasiewicz, Galván and Guisado, “Power Electronic Systems for the Grid Integration of Renewable Energy Sources: A Survey” IEEE transactions on industrial electronics, volume 53, number 4, August 2006 64 [18] K C Kalaitzakis and G J Vachtsevanos “On the Control and Stability of Grid Connected Photovoltaic Sources.” IEEE Transactions on Energy Conversion, Volume EC- 2, Number 4, December 1987 [19] R Magureanu, Mihaela, Dumitrescu, M Priboianu “A practical solution for grid connected dispersed generation from renewable sources: DC connection,” International Symposium on P.E., Electrical Drives, A and M, 2006 [20] C.V Nayar Control and Interfacing of Bi-directional Inverters for Off-Grid and Weak Grid Photovoltaic Power Systems 2000 IEEE [21] C Gonzalez-Moran, P Arboleya, Member, IEEE, G Diaz, Member, IEEE, J Gomez-Aleixandre Member, IEEE “Modeling Photovoltaic DC primary sources as grid connected inverter supplies considering non-linear effects,” IEEE Conference Electrical Power, Canada, 2007 [22] Mei Shan Ngan and Chee Wei Tan “A Study of Maximum Power Point Tracking Algorithms for Stand-alone PV Systems,” IEEE Applied power Electronics colloquium (IAPEC), 2011 [23] Martina Calais and Agelidis, “Multi level converter for single phase grid connected photovoltaic system an overview” 1998 IEEE [24] Gianfranco Chicco, Roberto Napoli and Filippo Spertino, “Experimental Evaluation of the Performance of Grid-Connected Photovoltaic Systems” IEEE MELECON 2004, May 12-15, 2004, Dubrovnik, Croatia [25] Massimo Aiello, Cataliotti, Salvatore, and Graditi, “Theoretical and Experimental Comparison of Total Harmonic Distortion Factors for the Evaluation of Harmonic and Inter harmonic Pollution of Grid-Connected Photovoltaic Systems” IEEE transactions on power delivery, Volume 21, Number 3, JULY 2006 [26] Hirotaka Koizumi, Mizuno, Takashi, Yukihisa, Norio, Manabu Kawasaki, Ken Nagasaka, and Kurokawa, “A Novel Microcontroller for Grid-Connected Photovoltaic Systems,” IEEE transactions on industrial electronics, Volume 53, Number 6, December 2006 [27] G Brando, Dannier, Rizzo, “Power Electronic Transformer application to Grid Connected Photovoltaic Systems” 2009 IEEE [28] Javier Chavarría, Domingo Biel, Francesc Guinjoan, Carlos Meza, , and Juan J Negroni, “Energy-Balance Control of PV Cascaded Multilevel GridConnected Inverters Under Level-Shifted and Phase-Shifted PWMs” IEEE 65 TRANSACTIONS ON INDUSTRIAL ELECTRONICS, Volume 60, Number 1, JANUARY 2013 [29] D.C Riawan and Nayar, “Analysis and Design of a Solar Charge Controller Using Cuk Converter” IEEE [30] P HUYNH and B H CHO, “Design and Analysis of a MicroprocessorControlled PPT System,” IEEE TRANSACTIONS ON AEROSPACE AND ELECTRONIC SYSTEMS Volume 32, Number 1, JANUARY 1996 [31] Kim, Hyunmin, “A New PPT for Cost-Effective Photovoltaic Power System” 0-7803-3547-3-7161 $ 4.00 1996 IEEE [32] G Brando, Dannier and Rizzo, “A Sensor less Control of H-bridge Multilevel Converter for Maximum Power Point Tracking in Grid Connected Photovoltaic Systems” 2007 IEEE [33] Theodore Amissah OCRAN, CAO Junyi CAO Binggang, SUN Xinghua, “Artificial Neural Network Maximum Power Point Tracker for Solar Electric Vehicle” TSINGHUA SCIENCE AND TECHNOLOGY I S S N 0 - 12/23 pp204-208, V o l u m e 10, N u m b e r 2, A p r i l 2005 [34] Koutroulis and Frede, ” A New Technique for Tracking the Global Maximum Power Point of PV Arrays Operating Under Partial-Shading Conditions” IEEE JOURNAL OF PHOTOVOLTAICS, Volume 2, Number 2, APRIL 2012 [35] Arun Kumar Verma, Bhim Singh, and D.T Shahani, “Fuzzy-Logic Based MPPT Control of Grid Interfaced PV Generating System with Improved Power Quality” 2012 IEEE [36] Ali Nasr Allah Ali1, Mohamed H Saied2, M Z Mostafa3, T M AbdelMoneim3, “A Survey of Maximum PPT techniques of PV Systems” 2012 IEEE 66