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Why a derivative controller is not used in the control system?

asked May 10 in Electrical by heinz867 | 5 views

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In PID controller the "D" derivative controller increases the stability of the system, reduces the overshoot and improves a transient response but they are never used alone because in case of sudden changes it will compensate the output fast and if error is constant it's output is zero and it will not work properly to get desire output. 
answered May 10 by Vsmaha21
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Derivative Controller (D-Controller)

With derivative action, the controller output is proportional to the rate of change of the measurement or error. The controller output is calculated by the rate of change of the deviation or error with time.

OD = - kD dEr / dt                           (3)

where

OD = output derivative controller

kD = derivative gain or action factor of the controller

dEr = deviation change over time sample dt

dt = time sample

The derivative or differential controller is never used alone. With sudden changes in the system the derivative controller will compensate the output fast. The long term effects the controller allow huge steady state errors.

A derivative controller will in general have the effect of increasing the stability of the system, reducing the overshoot, and improving the transient response.


answered May 10 by bhudevkumar