Anna University Coimbatore 2008 B.E Electrical and Electronics Engineering Control system QB - Question Paper

The proportional controller stabilizes the gain but produces a steady state fault. The integral control decreases or eliminates the steady state fault.
47. Why derivative controller is not used in control systems.
The derivative controller produces a control action based on the rate of change of fault signal and it does not produce corrective measures for any constant fault.
48. What is the disadvantage in proportional controller?
The disadvantage in proportional controller is that it produces a constant steady state fault.
49. What is the effect of PD controller on system performance?
The effect of PD controller is to increase the damping ratio of the system and so the peak overshoot is decreased.
50. Why derivative controller is not used in control system?
The derivative controller produces a control action based on rare of change of fault signal and it does not produce corrective measures for any constant fault. Hence derivative controller is not used in control system
51. What is the effect of PI controller on the system performance?
The PI controller increases the order of the system by one, which outcomes in reducing the steady state fault. But the system becomes less stable than the original system.
52. What is steady state error?
The steady state fault is the value of fault signal e (t) when t tends to infinity.
53. What are static fault constants?
The Kp, Kv, and Ka are called static fault constants.
54. What is the drawback of static coefficients?
The main drawback of static coefficient is that it does not show the variation of fault with time and input should be standard input.
55. What are the 3 constants associated with a steady state error?
Positional fault constant
Velocity fault constant
Acceleration fault constant
56. What are the main advantages of generalized fault co-efficient?
Steady state is function of time.
Steady state can be determined from any kind of input
57. What is frequency response?
The response of the system at the steady state when the input to the system is a sinusoidal signal is called as the frequency response.
50. List out the various frequency domain specifications?
The frequency domain specifications are
i) Resonant peak. ii) Resonant frequency.
51. Define –resonant peak (?r)?
The maximum value of the magnitude of closed loop transfer function is called resonant peak.
52. Define resonant frequency (fr)?
The frequency at which resonant peak occurs is called resonant frequency.

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