The document presents a control scheme for Doubly Fed Induction Generators (DFIG) integrated with variable speed wind turbines, focusing on maintaining terminal voltage and frequency stability. It includes the proposed control algorithm, simulation results, and discusses the impact of wind energy variations on energy conversion. The conclusion highlights reduced complexity in rotor-side converter control and improvements in grid synchronization using fuzzy logic techniques.

1. Control of Doubly Fed Induction
Generator connected to Variable Speed
Wind Turbine
IEEE International Conference on Technological
Advancements in Power and Energy-2015.
7/26/2016 TAP ENERGY-2015,Paper ID-270 1
Paper ID-270
Authors: Presented By
1. Anjana Jain B.Janardhan Reddy
Asst Professor, ASE, Bangalore
2. B.Janardhan Reddy TAP ENERGY-2015
PG student, ASE, Bangalore

2. Overview:
• Objective
• Introduction
• Block Diagram
• Proposed Control Algorithm
• Simulation Results
• Conclusion
• References
7/26/2016 TAP ENERGY-2015,Paper ID-270 2

3. Objective
• Derived the closed loop control scheme of DFIG.
• To maintain the terminal voltage and frequency constant.
• To maintain the slip power as negative in super synchronous mode of
operation and as positive in sub synchronous mode of operation.
By using bidirectional back-to-back SPWM converters connected to
rotor terminals.
7/26/2016 TAP ENERGY-2015,Paper ID-270 3

4. Introduction
• Wind Energy is a source of renewable power.
• Wind turbines harvest this kinetic energy and convert it into usable
power.
• In earlier period the technology used in WECS was based on SCIG
running at constant speed, directly connected to the grid.so wind
power is not utilized completely.
• Presently the technology moves towards the variable speed WECS and
hence influencing the system dynamics.
• But unbalances in wind energy are highly impacting the energy
conversion.
• Doubly fed induction generators (DFIG) are commonly used in wind
turbines to generate large amounts of electric power.
7/26/2016 TAP ENERGY-2015,Paper ID-270 4

5. Wind turbine:
• The maximum power extractable from the wind turbine is defined as
𝑃𝑚𝑎𝑥=
1
2
𝜌𝐴𝑉∞
3 𝐶 𝑝
=
1
2
∗ 1.225 ∗ 3.14 ∗ 153
∗ 0.46
=2985.84 𝑊
Parameters of Wind turbine
Radius = 1m
Pitch angle 𝛽 = 0 𝑑𝑒𝑔𝑟𝑒𝑒𝑠 for small wind turbines.
Wind velocity=15m/s for super synchronous mode and 5m/s for sub
synchronous mode of operation.
7/26/2016 TAP ENERGY-2015,Paper ID-270 5

6. Block diagram:
7/26/2016 TAP ENERGY-2015,Paper ID-270 6
For Pm=Ps+Pr
Ps=sPr
supersynchronous
speed operation
Pm=(1+s)Pr, s=-ve
For Pm=Ps+Pr
Ps=-sPr
subsynchronous
speed operation
Pm=(1-s)Pr, s=+ve
Fig:1 Structure of DFIG wind generation system

7. Characteristics of DFIG:
7/26/2016 TAP ENERGY-2015,Paper ID-270 7
Fig:2 Torque,current & slip characteristics of DFIG

8. Stator side converter control scheme:
7/26/2016 TAP ENERGY-2015,Paper ID-270 8
Fig:3 Stator side converter control

9. Proposed control algorithm for Rotor side converter:
7/26/2016 TAP ENERGY-2015,Paper ID-270 9
Fig:4 Proposed control algorithm for rotor side converter

10. Simulation circuit:
7/26/2016 TAP ENERGY-2015,Paper ID-270 10
Fig:5 Simulation circuit

11. Rotor speed Electromagnetic Torque
7/26/2016 TAP ENERGY-2015,Paper ID-270 11
Mechanical Torque Stator active power
SIMULATION RESULTS

12. Stator reactive power Stator Voltages
7/26/2016 TAP ENERGY-2015,Paper ID-270 12
Stator Currents DC Link Voltage

13. Rotor active power Rotor reactive power
7/26/2016 TAP ENERGY-2015,Paper ID-270 13
Rotor Voltages Rotor Currents

14. Grid Voltages Grid Currents
7/26/2016 TAP ENERGY-2015,Paper ID-270 14
Grid Synchronization THD for o/p Voltage Waveform

15. TABULATION FOR VARIOUS SPEED:
Speed in
wr
(rad/sec)
Mechanical Power in
Watts(W)
Slip (s) Stator Electrical Power in
Watts(W)
Rotor Electrical
Power in Watts(W)
DC link
voltage
162.3 Pm=(1+s)Pr=
Tm*wr=162.3*22=
3570.6 W
S=-0.03 Ps=Pm-Pr
=s*Pr=Te*ws=157*-22
=-3454 W
Pr
=-36.5W
Vdc=452.5V
158.5 Pm=158.5*6.9
=1093.65W
S=-0.009 Ps=157*-6.5
=-1020.5W
Pr=-8.5W Vdc=452.5V
156.5 Pm=(1-s)Pr
156.5*1.7=266.05W
S=0.0031 Ps=-s*Pr=157*-1.4
=-219.8W
Pr=2.3W Vdc=452.5V
154.3 Pm=154.3*1.5=232.5
W
S=0.012 Ps=157*-1.2=-188.4W Pr=5.2W Vdc=452.5V
7/26/2016 TAP ENERGY-2015,Paper ID-270 15
In steady state at fixed speed for a loss less generator is Tm=Te
Table 1: Tabulation for various speeds

16. Machine parameters:
• Type: Slip Ring Induction Motor Stator Resistance 𝑅 𝑠 = 4.781 𝛺
Power = 5HP=5*746=3.7KW Rotor Resistance 𝑅 𝑟 = 3.91 𝛺
Stator winding Stator Inductance 𝐿 𝑠 = 0.0248 𝐻
Voltage : 415 V Rotor Inductance 𝐿 𝑟 = 0.0248 𝐻
Current : 7.5 A Mutual Inductance 𝐿 𝑚 = 0.459 𝐻
Rotor winding Moment of Inertia 𝐽= 0.205 𝐾𝑔. 𝑚2
Voltage : 200 V Friction Factor 𝐵= 2.23𝑒−3
𝑁 − 𝑚
Current : 11 A Pole Pairs 𝑃= 2
7/26/2016 TAP ENERGY-2015,Paper ID-270 16

17. Conclusion:
• The complexity of the rotor-side converter control is reduced by
applying the proposed rotor control algorithm.
• Improvements in the grid-synchronization technique can be achieved
by applying the control technique using fuzzy logic to obtain
negligible oscillations in the various system parameters.
7/26/2016 TAP ENERGY-2015,Paper ID-270 17

18. References:
[1] R. Pena, J. C. Clare and G. M. Asher, “Doubly-Fed Induction Generator using back-to-back PWM converters and its application to
Variable-speed wind energy generation” IEEE Proceedings on Electrical Power Applications, Vol.143, No.3, pp. 231-241, May 1996.
[2] R. Pena, J. C. Clare and G. M. Asher, “Doubly-Fed Induction Generator using back-to-back PWM converters supplying an isolated
load from a Variable-speed wind turbine” IEEE Proceedings on Electrical Power Applications, Vol.143, No.5, pp. 380-387, Sep 1996.
[3] A.Jayalaxmi and Yerra Sreenivasa Rao “Direct Torque Control of Doubly Fed Induction Generator based wind turbine under
Voltage Dips” International Journal of Advances of Engineering & Technology, may 2012.
[4] Gilsung Byeon*, In Kwon Park** and Gilsoo Jang, “Modelling and Control of a Doubly-Fed Induction Generator (DFIG) Wind
Power Generation System for Real-time Simulations.
[5] S. Muller, M. Deicke, and R. W. De Doncker, “Doubly-Fed Induction Generator Systems for Wind Turbines,” IEEE Ind. Appl.Mag.,
Vol.8,n0. 3,pp. 26-33, May/Jun. 2002.
[6] R. Pena, J. C. Clare and G. M. Asher, “Doubly-Fed Induction Generator using back-to-back PWM converters and its application to
Variable-speed wind energy generation” IEEE Proceedings on Electrical Power Applications, Vol.143, No.3, pp. 231-241 May 1996.
[7] Srinath Vanukuru & Sateesh Sukhavasi “Active and reactive power control of a Doubly Fed Induction Generator driven by a Wind
Turbine.
[8] Rishabh Dev Shukla & Ramesh Kumar Tripathi “A novel Voltage and Frequency controller for standalone DFIG based Wind
Energy Conversion system.
[9] Iwanski G, Koczara W. “Sensorless direct voltage control method for standalone slip-ring induction generator.” In:Proceedings of
11th EPE, Dresden, Germany, CD-ROM; 2005.
[10] Bhim Singh, Fellow, IEEE, & N. K. Swami Naidu, “Direct Power Control of single VSC based DFIG without rotor position
sensor”, IEEE transaction on industry applications, vol. 50, no. 6, November/December 2014.
7/26/2016 TAP ENERGY-2015,Paper ID-270 18

19. THANK YOU
For Further Queries please
Contact @
thrishul007@gmail.com
7/26/2016 TAP ENERGY-2015,Paper ID-270 19