Power Electronics in Renewable Energy Systems …

1 Power Electronics in Renewable Energy Systems Power Electronics in Renewable Energy Systems by Prof. Dr. Frede Blaabjerg Aalborg University Institute of Energy Technology 21. - 09. - 2006 September 13, 2006, Gijon, Spain 1. 1. Power Electronics in Renewable Energy Systems Power Electronics in Renewable Energy Systems Outline in Energy Technology 2. wind Energy Systems 3. Solar Energy Systems 4. Summary 5. Future trends 21. - 09. - 2006 September 13, 2006, Gijon, Spain 2. 2. 1. Development in Energy Technology Where are we from? Power Electronics in Renewable Energy Systems DENMARK. 13000 students Founded in 1974. 21. - 09. - 2006 September 13, 2006, Gijon, Spain 3. 3. 1. Development in Energy Technology COMMUNICATION. Power Electronics in Renewable Energy Systems 3. Energy REFRIGERATOR. wind TURBINE. Storages PRIMARY. FUEL. SOLAR CELLS TELEVISION. DC. AC. SOLAR LIGHT. Energy TRANSFORMER. HEAT 3 3 3 1-3 MOTOR. LOADS. Power STATION TRANSFORMER PUMP. FACTS/CUPS.

2 ROBOTICS. Energy COMPEN- CHP SATOR. Storages INDUSTRY. FUEL DC. CELLS AC.. TRANSPORT Power SUPPLY. TRANSPORT. ac dc ~. FUEL =. COMBUSTION. ENGINE. Keywords: Energy production Energy distribution Energy consumption Energy control 21. - 09. - 2006 September 13, 2006, Gijon, Spain 4. 4. 1. Development in Energy Technology Organisation 20 Faculties 15 PhD. Power Electronics in Renewable Energy Systems Institute of Energy Technology 10 Guest Researchers 10 Research Assistansts 12 TAP. Power Fluid Thermal Energy Power Electrical Fluid Power electronic Mechanics and Systems Systems Machines Systems Systems Combustion Advanced Combustion and Drive Systems and Motion Virtual Power Prototyping Green Powers Converters Modern Power Systems Lab. Facilities: wind Turbine Systems Sustainable Transport Analysis and Planning Multiphase Processes Stratetic Power Electronics cooperation: Systems Emergent Projects EMSD Drive Systems Tests EDS Hydraulic CEES Power Systems NEED High Voltage Fuel cells Systems FACE DSpace Control Laser Systems Fuel Cell Systems Proto Type Facilities 21.

3 - 09. - 2006 September 13, 2006, Gijon, Spain 5. 5. 1. Development in Energy Technology Electricity production in 2004. Power Electronics in Renewable Energy Systems The share of Renewable Energy production is still very modest! 21. - 09. - 2006 September 13, 2006, Gijon, Spain 6. 6. 1. Development in Energy Technology Power capacities perspective until 2020. Power Electronics in Renewable Energy Systems The installed capacity has to increase by over 80%. New Power sources becomes interesting More efficient use of the existing sources From production to end user Power balance extremely important New Energy storage devices Distributed Power Generation Systems (DPGS) necessary 21. - 09. - 2006 September 13, 2006, Gijon, Spain 7. 7. 1. Development in Energy Technology Overview of DPGS. Power Electronics in Renewable Energy Systems Advantages of DPGS: wind Energy highest development Load management (peak shaving) Solar Energy next highest development Power quality (required by standards!)

4 Wave Energy largely unexplored Enhanced voltage stabiliity Tidal Energy largely unexplored Reduced transmission losses Small hydro (<10MW), 47GW used, 180 GW. Potential for improving grid untapped (70% in developing countries). reliability/stability Oldest technology (not covered). Disadvantage - high cost! Biomass 18GW used (2000), largely unexplored. Used in CHP. (not covered). 21. - 09. - 2006 September 13, 2006, Gijon, Spain 8. 8. 1. Development in Energy Technology Classical Power System Power Electronics in Renewable Energy Systems REFRIGERATOR. TELEVISION. LIGHT. TRANSFORMER. THERMAL. HEAT 3 3 3 1 -3. MOTOR. Power STATION (CHP) TRANSFORMER PUMP. ROBOTICS. 3. INDUSTRY. Power STATION. Power SUPPLY. ac dc ~. =. 3. Power STATION. Central Power plants 21. - 09. - 2006 September 13, 2006, Gijon, Spain 9. 9. 1. Development in Energy Technology Future Power System Power Electronics in Renewable Energy Systems REFRIGERATOR. SOLAR CELLS TELEVISION. DC. AC. SOLAR.

5 Thermal LIGHT. Energy . heat TRANSFORMER. 3 3 3 1-3 MOTOR. Power STATION (CHP) TRANSFORMER PUMP. FACTS. ROBOTICS. COMPEN- SATOR. INDUSTRY. TRANSFORMER FUEL DC. CELLS. AC. 3 Power SUPPLY. ac dc wind TURBINE ~. =. Demands Stability TRANSFORMER. Frequency control 3 Voltage control wind TURBINE Optimized control Focus in this Protection presentation Less central Power plants and more DPGS. 21. - 09. - 2006 September 13, 2006, Gijon, Spain 10. 10. Outline Power Electronics in Renewable Energy Systems 1. Development in Energy Technology Energy Systems 3. Solar Energy Systems 4. Summary 5. Future trends 21. - 09. - 2006 September 13, 2006, Gijon, Spain 11. 11. 2. wind Energy Systems Actual installed Power worldwide Power Electronics in Renewable Energy Systems The annual increase has decreased in 2004! 50 GW installed in 2005! Predicted for 2010 - 180 GW (source WindForce 10). 21. - 09. - 2006 September 13, 2006, Gijon, Spain 12. 12. 2. wind Energy Systems wind Turbine development Power Electronics in Renewable Energy Systems Bigger and more efficient !

6 Prototypes running (Vestas, GE, Siemens wind ,Enercon). Danish Vestas and Siemens wind stand for over 40% of the worldwide market 2MW WT are still the "best seller" on the market! 21. - 09. - 2006 September 13, 2006, Gijon, Spain 13. 13. 2. wind Energy Systems Danish experience 19% wind Power penetration! wind production can vary significantly Power Electronics in Renewable Energy Systems with respect to the predicted one This lead to instant export with low prices or import at high price Better wind prediction is needed 21. - 09. - 2006 September 13, 2006, Gijon, Spain 14. 14. 2. wind Energy Systems Power Conversion - MPPT. Power curve - Aerodynamic Cp Cp;max Power Electronics in Renewable Energy Systems 1 3. Ptur = Cp Av vwind 2. vtip rrt rt = = l vwind vwind Techniques to limit the produced Power Stall control Active stall control Pitch control For each wind speed, there is a different shaft rotation speed that leads to the extraction of the maximum available Power -->.

7 MPPT --> variable-speed WT. 21. - 09. - 2006 September 13, 2006, Gijon, Spain 15. 15. 2. wind Energy Systems Power Conversion and control Electrical Power wind Power Rotor Gearbox (optional) Generator Power converter Supply grid Power Electronics in Renewable Energy Systems (optional). Consumer Power conversion & Power transmission Power conversion Power conversion & Power transmission Power control Power control Electrical control Power control Pref Qref Basic Topologies Fixed speed with capacitor bank (old system, not used today anymore!). Two-generator principle two pole-pairs (exists in many Systems ). Rotor resistance control Doubly-fed induction generator DFIG - wounded rotor (very common now!). Squirell cage induction generator SCIG. Synchronous generator - External magnetized Synchronous generator - Permanent magnets 21. - 09. - 2006 September 13, 2006, Gijon, Spain 16. 16. 2. wind Energy Systems Basic topologies for variable-speed wind turbine Fixed speed with capacitor bank (Reactive Power ).

8 Power Electronics in Renewable Energy Systems 21. - 09. - 2006 September 13, 2006, Gijon, Spain 17. 17. 2. wind Energy Systems Basic topologies for variable-speed wind turbine Doubly-fed induction generator - wounded rotor Power Electronics in Renewable Energy Systems Limited speed range (-30% to +20%, typical). Small-scale Power converter (Less Power losses, price). Complete control of active Pref and reactive Power Qref Need for slip-rings Need for gear V. Doubly-fed induction generator Grid Gear Pitch AC DC. DC AC. Pref Qref 21. - 09. - 2006 September 13, 2006, Gijon, Spain 18. 18. 2. wind Energy Systems Basic topologies for variable-speed wind turbine Induction generator - Squirrel cage rotor Power Electronics in Renewable Energy Systems Full speed range No brushes on the generator Complete control of active og reactive Power Proven technology Full-scale Power converter Need for a gear VI. Induction generator Grid AC DC. Gear DC AC. Pitch Pref Qref 21.

9 - 09. - 2006 September 13, 2006, Gijon, Spain 19. 19. 2. wind Energy Systems Basic topologies for variable-speed wind turbine Synchronous generator - Permanent magnets Power Electronics in Renewable Energy Systems Full speed range Possible to avoid gear (multi-pole generator). Complete control of active and reactive Power Brushless (reduced maintenance). No Power converter for field (higher efficiency). Full scale Power converter Multi-pole generator big and heavy Permanent magnets needed in large quantities IX. PM-synchronous Generator Multi-pole Grid AC DC. DC AC. Pitch Pref Qref 21. - 09. - 2006 September 13, 2006, Gijon, Spain 20. 20. 2. wind Energy Systems Comparison of topologies Power Electronics in Renewable Energy Systems System comparison of wind turbines System I II III IV V VI VII VIII IX. Variable speed No No No No Yes Yes Yes Yes Yes Control active Power Limited No Limited Limited Yes Yes Yes Yes Yes Control reactive Power No No No No Yes Yes Yes Yes Yes Short circuit (fault-active) No No No No No/Yes Yes Yes Yes Yes Short circuit Power contribute contribute contribute contribute contribute limit limit limit limit Control bandwidth 1-10 s 1-10 s 1-10 s 100 ms 1 ms ms ms ms ms Standby function No No No No Yes + Yes ++ Yes ++ Yes ++ Yes ++.

10 Flicker (sensitive) Yes Yes Yes Yes No No No No No Softstarter needed Yes Yes Yes Yes No No No No No Rolling capacity on grid Yes, partly No Yes, partly Yes, partly Yes Yes Yes Yes Yes Reactive compensator (C) Yes Yes Yes Yes No No No No No Island operation No No No No Yes/No Yes/No Yes/No Yes/No Yes Investment ++ ++ ++ ++ + 0 0 0 0. Maintenance ++ ++ ++ ++ 0 + + + +. Power Electronics now enables wind Energy as a Power soource 21. - 09. - 2006 September 13, 2006, Gijon, Spain 21. 21. 2. wind Energy Systems Technology comparison Power Electronics in Renewable Energy Systems Fixed speed DFIG. Rotor Resistance Control Full Scale Power Converter - Power Electronics is now in wind turbines 21. - 09. - 2006 September 13, 2006, Gijon, Spain 22. 22. 2. wind Energy Systems Current developments, Vestas A/S Denmark Power Electronics in Renewable Energy Systems Vestas V120 off-shore turbine Rated Power : 4,500 kW. Rotor diameter: 120 m Hub height: 90 m Turbine concept: Gearbox, variable Target market: Big off-shore farms speed, variable pitch control Generator: HV DFIG.