Reconsideration of loop gain measurement of DC/DC converters

There are mainly two existing loop gain measurement methods, which are the modulating signal perturbation method (MSPM) and the pulse-width signal perturbation method (PSPM). This paper points out that there are differences between these methods, and the loop gain measured by the PSPM can be more easily used in the guidance of the controller design. Since the circuit implementation of the PSPM is not easy, the additional PWM modulation method (APMM) and the sample-and-hold method (SHM) with uncomplicated circuits are proposed. The experiment results verify the correctness of the theoretical analysis and the proposed loop gain measurement methods.