1 P a g e VALLIAMMAI ENGINEERING COLLEGE SRM NAGAR, KATTANKULATHUR 603203 DEPARTMENT OF ELECTRICAL AND ELECTRONICS ENGINEERING PX7301 Power Electronics for Renewable Energy Systems UNIT-I PART-A 1. Give any two environmental aspects of electric energy conversation. 2. Discuss about GHG emission? List the factors influencing the amount of GHG emissions. 3. List various renewable energy resources. 4. Summarize the significance of renewable energy. 5. Discriminate spring and neap tides? 6. Explain the principle of power generation using tides? 7. List the limitations of Tidal energy. 8. Compose various ocean tidal energy conversion schemes available. 9. Discuss about anaerobic digestion? And its advantages. 10. Discuss how to use hydrogen energy to generate electric power? 11. Identify the problems associated with tapping solar energy? 12. Summarize the factors influencing solar power extraction? 13. Identify the limitation of solar power. 14. Explain about NOCT and STC of a solar cell. 15. Discuss about fuel cell and mention its specification. 16. Show fuel cell characterization? 17. Classify the types of fuel cell? 18. Point out the impact of wind power penetration in power grid. 19. Explain how to assess the wind energy pattern for a particular location. 20. List the wind turbine used for domestic application.
2 P a g e PART-B 1. Discuss the impact of renewable energy generation on environment. (13) 2. Discuss the qualitative study of different renewable energy resources. (13) 3. Describe various biomass energy conversion techniques. (13) 4. Compare the power extraction aspects of solar PV system with wind energy system. (13) 5. (i) Describe the consequences of green house effect(6) (ii)describe the prospects of ocean and biomass energy(7) 6. How does environment get affected by the use of the renewable energy? And also discuss GHG emissions from the various energy sources. (13) 7. Explain the working principle of various types of concentrating solar collectors with neat sketch. (13) 8. Show various types of wave energy conversion device and explain how to generate electrical power from waves. (13) 9. Describe the principle of generation of Bio gas and mention the factors affecting its generation. (13) 10. Describe the operation and control strategy of solar power conversion systems. (13) 11. Illustrate the design and principle of operation of general Fuel cell and Fossil Fuel cell. (13) 12. (i)show the different types of ocean thermal energy conversion power plants? (6) (ii)illustrate in detail the Anderson OTEC cycle.(7) 13. What is Hydrogen energy? Explain the operation of Hydrogen energy system with a neat schematic. (13) 14. Explain the following with neat schematic. i. Wind energy conversion system(7) ii. Energy from the Ocean(6) PART-C 1. (i) Brief explain about some of the renewable energy sources.(5) (ii)show how a dc-dc converter can be used as a part of an inverter designed to have a square wave output of 48V with a 12V dc input. The idea is to design the inverter without a transformer. Sketch a block diagram, showing design components to clearly express your design.(10)
3 P a g e 2. Two 36 cell PV modules are connected in series. One is shaded and one is fully illuminated, Assume ideal IV characteristics for the module (i) If the output of the two series module is shorted, Formulate the power dissipated in the shaded module. (ii) If the two modules are equipped with bypass diodes across each 12 series cells, Formulate the power dissipated in the shaded module.(15) 3. Explain briefly the influence of different renewable energy sources with special reference to the global warming context.(15) 4. Compare the environmental aspects of renewable and non-renewable energy conversion system.(15) UNIT-II PART-A 1. Define reference theory. 2. Explain the principle of operation of induction generators? 3. Distinguish induction generator and synchronous generator. 4. Show the merits of squirrel cage induction generators for wind energy conversion? 5. Define Clarke transformation. 6. Define Park transformation. 7. Summarize the significance of induction generator based wind power generation. 8. Why are induction generators preferred over dc generators in WECS.Justify 9. Give the advantages of IG used in WECS? 10. Label slip-torque characteristics of induction generator. 11. Illustrate the principle of PMSG. 12. Show the merits of PMSG for WECS? 13. Express the steady state equation of a PMSG. 14. List the advantages of PMSG. 15. Label the slip-torque characteristics of PMSG. 16. Differentiate between synchronous generator and PMSG. 17. Compose the characteristics of SCIG? 18. Explain DFIG. 19. Compose the characteristics of DFIG? 20. Differentiate between SCIG and DFIG.
4 P a g e PART-B 1. Define reference theory and also explain about the fundamentals of reference theory. (13) 2. Describe the following (a) Clarks Transformation(6) (b) Parks Transformation(7) 3. (i)explain construction, principle of working and characteristics of IG with neat sketches.(8) (ii) Analyse the merits and demerits of the above.(5) 4. (i)explain with a neat diagram the operation of an induction generator.(7) (ii)compose the merits and demerits of mains excited and capacitor excited induction generator. (6) 5. Show the principle and operation of induction generator for wind energy conversion system. (13) 6. Explain the analysis of Induction Generator used for Wind Energy Conversion System. (13) 7. Explain machine capacity factor and capacity utilization factor. Explain the principle of operation of double output induction generator system with neat diagram. (13) 8. (i)label the schematic of Permanent Magnet Synchronous generator and explain the construction and principle of operation in detail. (7) (BTL- 1) (ii)also discuss the characteristics and issues briefly. (6) 9. With the neat diagram, Show the principle of PMSG and analyse in detail. (13) 10. (i)discuss the working and operation of PMSG with neat diagram.(7) (ii)draw and describe the characteristics of DFIG. (6) 11. (i)discuss the principle and construction of SCIG.(7) (BTL- 2) (ii)discuss the operation of SCIG in details with proper analysis.(6) 12. Discuss about DFIG based energy conversion system. (13) 13. Describe the principle of operation of DFIG with neat diagram used for renewable energy conversion. (13) 14. (i)compose briefly construction, principle of working of SCIG with neat sketches. (7) (ii)draw and explain the characteristics of SCIG.(6)
5 P a g e PART-C 1. Draw the circuit model of self-excited induction generator and explain the methods used for steady state analysis..(15) 2. Draw the circuit model of PMSG and explain the methods used for steady state analysis..(15) 3. (i)explain the characteristics of SCIG? (6) (ii)what is the characteristics of SCIG used for renewable energy conversion. Explain it.(9) 4. Explain DFIG based wind power generation. Illustrate the independent dq control strategy adopted for dq control. (15) UNIT-III PART-A 1. Label the block diagram of solar photovoltaic system. 2. Discuss line commutated converters? Draw the schematic diagram. 3. Explain inversion mode of operation of line commutated inverter? 4. List the advantages of dc link inverters. 5. Summarize the role of capacitor and the minimum value required for the boost converter. 6. Generalize the significance of buck boost converter? 7. Give the schematic diagram of buck boost converter. 8. List the advantages of boost and buck converter. 9. Discuss about battery sizing? 10. Explain the various aspects of battery sizing. 11. Define array sizing. 12. Show the delicacies involved in sizing the solar arrays. 13. Identify the factors to be considered for the selection of inverter and batteries for solar energy conversion? 14. Identify limitations of AC voltage controller? 15. Give the advantages of uncontrolled rectifier? 16. Show the advantages of dc link inverters? 17. Explain grid interactive inverter? 18. Explain matrix converters. Compose its merits. 19. Show the limitations in the operation of matrix converter. 20. Explain where are matrix converters can be used.
6 P a g e PART-B 1. Draw the block diagram of the solar PV system and describe the principle of operation in detail. (13) 2. Draw and compose the converter topologies used for solar power generation. (13) 3. Explain the converters used for solar energy conversion. (13) 4. (i)explain with neat diagram the philosophy of operation of a solar source fed boost converter.(7) (ii) Point out the delicacies involved in sizing the solar arrays.(6) 5. Describe the operation of line commutated converter under inversion mode with the help of a neat circuit diagram and necessary waveforms. (13) 6. Draw the schematic diagram of Buck-Boost converter and explain the operation in detail. (13) 7. Describe the following in detail: i. AC voltage controller(7) ii. Voltage control in PWM inverters.(6) 8. (i)explain the working of AC-DC-AC converter with circuit and wave form for wind energy conversion.(7) (ii) Analyse the principle of working of buck-boost converter with time ratio and current limit control. Draw the circuit and necessary waveforms.(6) 9. Discuss the following (i)selection of inverters(5) (ii)battery sizing(4) (iii)array sizing(4) 10. (i)discuss the three phase uncontrolled rectifiers in details(7) (ii)give short notes on PWM inverters. (6) 11. (i) Describe the principle and operation of line commutated converters in inverse mode.(7) (ii)describe principle of operation of PWM inverter and describe how it is used for wind energy conversion.(6) 12. Describe the grid interactive inverters in detail. (13) 13. (i)show how a three phase line commutated converter is operated as an inverter.(7) (ii)show the limitation in the operation of matrix converters. (6) 14. Illustrate the working and operation of a matrix converter with a neat diagram. (13)
7 P a g e PART-C 1. Consider a buck boost converter of input voltage E dc =14V. The duty cycle α=0.6 and the switching frequency is 25kHZ. The inductance L=180µH and the filter capacitance C=220µF. The average load current I o =1.5A. Formulate the average output voltage and peak current of the device. (15) 2. A single phase full bridge inverter has a resistive load of R=3Ω and the DC input voltage is E dc =50V. Formulate the RMS output voltage at the fundamental frequency, the output power, the average and peak currents of each thyristor and peak reverse blocking voltage of each thyristor..(15) 3. Explain about various aspects of grid interactive inverters..(15) 4. (i)design a PV array sizing algorithm for finding out number of series and parallel PV array sizing. (5) (ii)also explain the role of PV system in telecommunication system(5) (iii)design of PV array for domestic application. (5) UNIT-IV PART-A 1. Discuss fault ride through capability? 2. Define energy payback period? 3. Label the basic block diagram of WECS. 4. Illustrate about opti slip concept used in wind energy conversion system. 5. Why pitch angle control is used for WECS? Justify. 6. Discuss stand-alone operation of fixed speed WECS? State its advantages. 7. Generalize the limitations of fixed speed induction generator based wind power conversion. 8. Differentiate between fixed and variable speed wind energy conversion systems. 9. Summarize the impact of high penetration of wind power in to power grid? 10. Discuss some of the standards used for grid integration. 11. List few grid connection requirement of renewable power system.
8 P a g e 12. List out grid interconnected issues. 13. Show how the power quality issues that affect wind power integration. 14. Point out the major problems related with grid interconnections of WECS? 15. Label the schematic diagram grid integrated PMSG based WECS.Also mention its demerits 16. Point out the issues created in grid integrated PMSG based WECS? 17. Show the schematic diagram of grid integrated SCIG based WECS. 18. Define grid integrated solar system. 19. Point out the problems in grid integrated solar system. 20. What will happen if no load is connected to a solar PV system. PART-B 1. Describe the power conditioning schemes used in WECS. (13) 2. Explain the stand alone operation of (i)fixed speed wind energy conversion system.(5) (ii)variable speed wind energy conversion system.(5) (iii) State the advantages of fixed speed system over variable speed systems.(3) 3. Explain stand alone operation of fixed and variable speed solar energy conversion system. (13) 4. Give a short notes on (i) Grid integrated PMSG (7) (ii) SCIG based WECS (6) 5. (i)explain with the help of a neat block diagram the functions of various blocks of a WECS. (7) (ii)a HAWT is installed at a location having free wind velocity of 15m/s. The 80m diameter rotor has three blades attached to the hub. Calculate the rotational speed of the turbine for optimal energy extraction. (6) 6. Show the various grid connected issues and its impact on system stability. (13) 7. (i)show the working and operation of PMSG with neat diagram. (7)
9 P a g e (ii)draw and explain the characteristics of DFIG. (6) 8. Discuss on Grid integrated PMSG operation with a neat diagram. (13)BTL-2) 9. Describe about SCIG based WECS. (13) 10. Compose a short notes on grid integrated solar system. (13) 11. Describe stand alone operation of wind energy conversion system. (13) 12. Describe stand alone operation of solar energy conversion system. (13) 13. Discuss in detail the grid system characteristics and explain with a neat diagram the stand alone and grid integrated solar system. (13) 14. Explain about grid integrated PMSG based WECS. (13) PART-C 1. Explain the grid related problems in wind farms and refer the performance improvements of generator controls..(15) 2. Explain with an example how to control the harmonics and improve the power quality when solar PV connected to the grid..(15) 3. (i)explain with the aid of a diagram the operation of a grid integrated solar photo voltaic system(8) (iii) Explain how the isolation and temperature affects the I-V characteristics of a solar cell.(7) 4. Summarize the concepts of Grid Integrated solar system and the grid related problems. Explain with a case study..(15) UNIT-V PART-A 1. Define hybrid systems? 2. Compose the need for hybrid energy systems? 3. Explain the range of hybrid systems? 4. Summarize the benefits of the hybrid energy systems? 5. List out some of the hybrid systems used in industries. 6. Classify the types of hybrid system with range. 7. Point out the merits of wind-diesel hybrid system. 8. Label the schematic diagram of PV-Diesel hybrid system.
10 P a g e 9. Show the advantages of PV-Diesel hybrid system. 10. Define charge controller used for wind energy conversion system 11. Explain MPPT? 12. Show the need for maximum power point tracking? 13. What will happen if no load is connected to a solar PV system? 14. List the merits of Hybrid RES over the isolated RES? 15. Give the applications of solar PV system? 16. Label the schematic diagram of grid interactive solar PV system. 17. Discuss the significance of MPPT. 18. Summarize the importance of MPPT in the operation of a photo voltaic system. 19. Discuss the major features of hybrid system? 20. Classify the types of pumps used for solar water pumping applications? PART-B 1. Explain the hybrid energy conversion system with neat sketch. (13) 2. Explain the design aspects of hybrid renewable energy systems. (13) 3. Define hybrid system? Discuss the need for hybrid system and its range and type. (13) 4. Explain MPPT techniques for WECS. (13) 5. (i)summarize the importance of MPPT in the operation of a photovoltaic system.(7) (ii)explain various strategies used for the operation of an MPPT.(6) 6. Describe the operating principle of PV Maximum Power Point Tracking in energy conversion. (13) 7. Show briefly the maximum power point tracking system. (13) 8. Discuss and classify the working of MPPT in a solar PV system. (13) 9. Discuss with case study how to get maximum power generation in wind energy conversion system. (13) 10. Show with case study how to get maximum power generation in solar energy conversion system. (13)
11 P a g e 11. With a neat sketch, describe the operation of PV-Diesel hybrid system. (13) 12. Draw and describe the operation of Wind-PV hybrid system. (13) 13. Describe the case studies of wind. (13) 14. Design solar PV pump and clearly explain the accessories required. Also justify the importance of implementing MPT for the pump system. (13) PART-C 1. Explain the methods to integrate hybrid solar PV and wind energy conversion system to the grid with neat block diagram..(15) 2. Formulate an expression for the total cost of a hybrid system and three from deduce a simple condition for the feasibility of the system..(15) 3. Is wind energy an excellent supplement to the PV? IF so justify with a suitable case study.(15) 4. What is MPPT? Discuss the types of MPPT with its merits and demerits? Explain the incremental conduction Algorithm with a neat example. (15)