Impulse Response Analysis

An alternative and faster method to determine the open loop transfer function of a system is the Impulse Response Analysis. Instead of perturbing a system with sinusoidal stimuli of different frequencies, one at a time, a single impulse is applied when the system is in steady state. The system transfer function can then be calculated very efficiently over a wide frequency range (from zero to half the system frequency) by computing the Laplace transform of the transient impulse response.

Algorithm

The impulse response analysis is performed in three steps:

1. Find the steady-state operating point of the system under study.

2. Apply a perturbation in form of a discrete impulse for the duration of one period.

3. Calculate the Laplace transform of the transient impulse response.

Reference

• D. Maksimović, “Automated small-signal analysis of switching power converters using a general-purpose time-domain simulator”, Proc. Applied Power Electronics Conference, February 1998.