Modified PID Load-Frequency Control with the Consideration of Valve Position Limits

1. Modified PID Load-Frequency Control with the Consideration of Valve Position Limits 授課老師：曾慶耀 教授 姓名:余萬勇 學號:M97670006

2. Conventional LFC Scheme the open-loop transfer function

3. Proposed LFC Control Scheme

4. CASE 1 : without Integral Control Loop (KI = 0) • the open-loop transfer function

5. When KD = 0.4 Angles of asymptotes : Asymptote intersect : Breakaway points :

6. When KD = 0.3 Angles of asymptotes : Asymptote intersect : Breakaway points :

7. which yields KD,crit＝0.074 Therefore, the system stability can be absolutely guaranteed as long as the derivative gain KD is selected greater than the critical value KD,cirt

8. CASE 2 : with Integral Control Loop (KI ≠ 0 ) • the open-loop transfer function

9. When KD = 0.4，KI = 0.7 When KD = 0.3，KI = 0.2

10. KD,crit =0.074 which yields KI,crit= 3.680

11. Consequently, it is concluded that the proposed LFC scheme including the integral feedback loop also guarantees the system stability as long as the derivative gain KDis greater than a critical valueKD,critand the integral gain KIless than KI,crit

12. Modeling of Hydraulic Pilot with the Consideration of Valve Position Limits

14. Simulation results

16. END