A Low-cost Voltage Stabilization and Power Quality Enhancement Scheme for a Small Renewable Wind Energy Scheme

1. A Low-cost Voltage Stabilization and Power Quality Enhancement Scheme for a Small Renewable Wind Energy Scheme By Dr. A.M Sharaf (SM-IEEE) Dept. of Electrical and Computer Engineering University of New Brunswick

2. OUTLINE • Introduction • System Description • Novel PWM Switching Control Scheme • Modulated Power Filter Compensator • Simulation Results • Conclusion

3. Introduction • Motivation of renewable wind energy • Fossil fuel shortage and its escalating prices • Reducing environmental pollution caused by conventional methods for electricity generation

4. Introduction • Challenges of the reliability of wind power system • Load excursion • Wind velocity variation • Conventional passive capacitor compensation devices become ineffective

5. System Description • Self-excited induction generator (SEIG) • Transformers and short feeder • Hybrid loads: linear load and non-linear load • The modulated power filter compensator (MPFC)

6. Novel PWM Switching Control Scheme

7. Novel PWM Switching Control Scheme • Multi-loop dynamic error driven • The voltage stabilization loop • The load bus dynamic current tracking loop • The dynamic load power tracking loop • Using proportional, integral plus derivative (PID) control scheme • Simple structure and fast response

8. Novel PWM Switching Control Scheme • Objective: • To stabilize the voltage under random load and wind speed excursion • Maximize power/energy utilization • The control gains (Kp, Ki) are selected using a guided trial and error method to minimize the objective function, which is the sum of all three basic loops.

9. The Functional Model of MPFC • The capacitor bank and the RL arm are connected by a 6-pulse diode to block the reverse flow of current. • Capacitor size normally selected as 40%-60% of the non-linear load KVAR capacitor.

10. Proposed MPFC Scheme and Its Functional Model

11. Simulation Results • Digital simulation environment: • MATLAB 7.0.1/SIMULINK • Sequence of load excursion: • From 0s to 0.2s: Both Linear Load 200 kVA (50%) and nonlinear Load 200 kVA (50%) connected • From 0.2s to 0.4s: Linear Load 200 kVA(50%) connected only • From 0.4s to 0.6s: No load is connected

12. System Dynamic Response Without MPFC

13. System Dynamic Response With MPFC

14. Error plane of the dynamic error driven controller

15. Conclusion • The digital simulation results validated that the proposed low cost MPFC scheme is effective in voltage stabilization for both linear and nonlinear electrical load excursions. • The proposed MPFC scheme will be easily integrated in renewable wind energy standalone units in the range from 600kW to 1600kW.

16. Reference • [1] A.M.Sharaf and Liang Zhao, ‘A Novel Voltage Stabilization Scheme for Standalone Wind Energy Using a Facts Dual Switching Universal Power Stabilization Scheme’, 2005 • [2] M.S. El-Moursi and Adel M. Sharaf, 'Novel STATCOM controller for voltage stabilization of wind energy scheme', Int. J. Global Energy Issues, 2006 • [3] A. M. Sharaf and Guosheng Wang, ‘Wind Energy System Voltage and Energy Enhancement Using Low Cost Dynamic Capacitor Compensation Scheme’, 2004 • [4] A.M. Sharaf and Liang Yang, 'A Novel Efficient Stand-Alone Photovoltaic DC Village Electricity Scheme’, 2005

17. Reference • [5] Pradeep K. Nadam, Paresk C. Sen, 'Industrial Application of Sliding Mode Control', IEEE/IAS International Conference On Industrial Automation and Control, Proceedings, pp. 275-280, 1995 • [6] Paresk C. Sen, 'Electrical Motor and Control-Past, Present and Future', IEEE Transactions on Industrial Electronics, Vol.37, No.6, pp.562-575, December 1990 • [7] Edward Y.Y. Ho, Paresk C. Sen, 'Control Dynamics of Speed Drive System Using Sliding Mode Controllers with Integral Compensation', IEEE Transactions on Industry Applications, Vol.21, NO.5, pp 883-892, September/October 1991.