ELE 302 Lecture 17: 17
19 Oct 2017
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Document Summary
The above expression for the system response is again a superposition of two components: a step response of the standard second order model, and a derivative of the same step response, but with a multiplier 1/a. Depending on the magnitude of a, this component may be small or large. Thus if a is large, i. e. the zero is far away in the lhp, the magnitude of this derivative term is insignificant and can be safely ignored. However, if the zero is placed in the significant region close to the imaginary axis, the magnitude of this signal component rapidly increases. The superposition of a signal and its derivative creates a large hump in the system response, in essence an exaggerated percent overshoot. As an example, consider a second order overdamped system with poles at. 5 and 3, and an additional zero at a = 50:
