H∞ loop-shaping control of a buck-boost converter

In this paper, robust control techniques are used to design a buck-boost dc-dc power converter. The robust control techniques used in this paper are based on frequency-domain controller design ideas, and the stability margins of the two controllers designed in this paper allow us to guarantee that both controllers provide robust stability. That is to say, the transfer function of the power converter belongs to a set, which can be either structured or unstructured, and the internal stability of the feedback-controlled system holds for every plant in the above-mentioned set. In this paper we design both a proportional integral derivative (PID) controller and an H_∞ controller, and the experimental results are satisfactory and show that the H_∞ controller rejects disturbances at both the input and output of the plant better than the PID controller.