Control and Performance Assessment of Variable Rotor Resistance Based Wind Turbines Regarding the Aerodynamic Power Fluctuations

Document Type : Article


Department of Electrical and Computer Engineering, University of Kashan, Kashan, Iran


This paper first deals with the analytical controller design in wind turbines with variable rotor-resistance control. Wind turbines with variable rotor-resistance control, known as limited variable speed wind turbine (LVS-WT), provide a limited variation of the generator speed. In the LVS-WT, the rotor current and consequently the output power can be controlled by varying the rotor resistance. Then modal and small signal analysis of the wind turbine is examined. It is found that for certain value of shaft stiffness, frequency of the mechanical modes coincides with the triple oscillation frequency appeared due to tower shadow effects. This in turn results in resonance phenomena magnifying the fluctuation of the generator power and electromagnetic torque. The paper next evaluates the impact of aerodynamic torque fluctuations on the dynamic response of the LVS-WT. In this way, analytical expressions for the fluctuations of the stator voltage and current, electromagnetic torque, and generator active power are proposed. These fluctuations arise as a consequence of the aerodynamic torque and rotor speed perturbations. The paper also investigates the effects of shaft stiffness, slope of power-slip curve and rotor resistance on the wind turbine response. At the end, results of theoretical analyses are verified by time domain simulations.


Main Subjects

1. Rahimi, M. and Parniani, M. Dynamic behavior and
transient stability analysis of xed speed wind turbines",
Renewable Energy, 34, pp. 2613-2624 (2009).
2. Rahimi, M. and Parniani, M. Grid-fault ride-through
analysis and control of wind turbines with doubly fed
induction generators", Elec. Power Sys. Res., 80, pp.
184-195 (2010).
3. Vittal, V. and Ayyanar, R., Grid Integration and
Dynamic Impact of Wind Energy, 1st Ed., Springer
4. Jatinkumar, P., Gupta, S.P., and Singh, S.P. Comparison
of control techniques for rotor current control
of line-excited slip-ring IG for WECS", Proc. Int.
Conf. Computational Intelligence and Communication
Networks (CICN) (2010).
5. Tsourakis, G., Nomikos, B.M., and Vournas, C.D.
E ect of wind parks with doubly fed asynchronous
generators on small signal stability", Elec. Power Sys.
Res., 79, pp. 190-200 (2009).
6. Dominguez-Garcia, J.L., Gomis-Bellmunt, O.,
Bianchi, F.D., and Sumper, A. Power oscillation
damping supported by wind power: A review",
Renewable and Sustainable Energy Reviews, 16, pp.
4994-5006 (2012).
7. Pannell, G., Atkinson, D.J., and Zahawi, B. Analytical
study of grid-fault response of wind turbine
doubly fed induction generator", IEEE Trans. Energy
Conversion, 25, pp. 1081-1091 (2010).
8. Rola, X., NA, CO., Rcoles, F., and Pedra, J. Doubly
fed induction generator subject to symmetrical voltage
sags", IEEE Trans. Energy Conversion, 26, pp. 1219-
1229 (2011).
9. Rahimi, M. and Parniani, M. Coordinated control
approaches for low-voltage ride-through enhancement
in wind turbines with doubly fed induction generators",
IEEE Trans. Energy Conversion, 25, pp. 873-
883 (2010).
10. Rahimi, M. and Parniani, M. Low voltage ridethrough
capability improvement of DFIG-based wind
turbines under unbalanced voltage dips", Electrical
Power and Energy Systems, 60, pp. 82-95 (2014).
11. Anaya-Lara, O., Hughes, F.M., Jenkins, N., and
Strbac, G. Contribution of DFIG- based wind farms
to power system short-term frequency regulation", IEE
Proc. Gen. Transm. Distri., 153, pp. 164-70 (2006).
12. Mauricio, J.M., Marano, A., Gomez-Exposito, A., and
MartinezRamos, J.L. Frequency regulation contribution
through variable-speed wind energy conversion
systems", IEEE Trans. Power Systems, 24, pp. 173-
180 (2009).
13. Muyeen, S., Ali, M., Takahashi, R., Murata, T.,
and Tamura, J. Damping of blade-shaft torsional
oscillations of wind turbine generator", Electric Power
Components and Systems, 36, pp. 195-211 (2008).
14. Yang, L., Xu, Z., Ostergaard, J., Dong, Z., Wong,
K., and Ma, X. Oscillatory stability and eigenvalue
sensitivity analysis of a DFIG wind turbine system",
IEEE Trans. Energy Convers., 26, pp. 328-339 (2011).
15. Dolan, D.S.L. and Lehn, P.W. Simulation model of
wind turbine 3p torque oscillations due to wind shear
and tower shadow", IEEE Trans Energy Convers., 21,
pp. 717-724 (2006).
16. Hu, W., Su, C., and Chen, Z. Impact of wind shear
and tower shadow e ects on power system with large
scale wind power penetration", IEEE Conf. Industrial
Electronics Society (IECON) (2011).
17. Burnham, D.J., Santoso, S., and Muljadi, E. Variable
rotor-resistance control of wind turbine generators",
IEEE Conf. Power & Energy Society General Meeting
M. Rahimi/Scientia Iranica, Transactions D: Computer Science & ... 25 (2018) 1593{1607 1607
18. Chan, T.F., Nigim, K.A., and Lai, L.L. Voltage and
frequency control of self-excited slip-ring induction
generators", IEEE Trans Energy Conversion, 19, pp.
81-87 (2004).
19. Rahimi, M. and Parniani, M. Ecient control scheme
of wind turbines with doubly-fed induction generators
for low voltage ride-through capability enhancement",
IET Journal Renewable Power Generation, 4, pp. 242-
252 (2010).
20. Rahimi, M. and Parniani, M. Dynamic behavior
analysis of doubly-fed induction generator wind turbines
- The in
uence of rotor and speed controller
parameters", Electrical Power and Energy Systems,
32, pp. 464-477 (2010).
21. Ackerman, T., Wind Power in Power Systems, 1st Ed.,
Wiely (2005).
22. Kundur, P., Power System Stability and Control, 2nd
Ed., McGraw-Hill (1994).