AC-Domain Comparison of Switched Mode Power Supply

Designing control system of dc/ dc converters involves accurate measurement of every transfer function form the control input of the system to the measured state variable, that is controlled. The simple case of voltage mode control of dc/dc converters is easy to experimentally verify, as there is no ambiguity where the perturbation signal from the vector network analyzer may be inserted. This is not the case for current-mode control, where the two closed loops are present and the perturbation may be inserted in everyone of them. How to measure the closed loop transfer functions in this case is the spotlight of this paper.