Question

The transfer function of a phase-lead controller is given by

(a) (1+aTs)/(1+Ts) , a>1 T>0

(b) (1+aTs)/(1+Ts) , a<1 T>0

(c) (1-aTs)/(1+Ts) , a>1 T>0

(d) (1±Ts)/(1+Ts) , a<1 T>0

This question was posed to me in unit test.

Enquiry is from Experimentation of Transfer Function in division Frequency Response Analysis of Control Systems

Answer 1

Right choice is (a) (1+aTs)/(1+Ts) , a>1 T>0

The best explanation: For the phase lead controller in which the stability and speed of response is more for the system, the magnitude of the pole must be greater than the magnitude of the zero.