Uncertainty models for switch-mode DC-DC converters

Uncertainty models for the three basic switch-mode converters, buck, boost, and buck-boost, are given in this paper. The resulting models are represented by linear fractional transformations (LFT's) with structured dynamic uncertainties. Uncertainties are assumed for the load resistance R = R-o(1 + delta(R)), inductance L = L-o(1 + delta(L).), and capacitance C = C-o(1 + delta(C)). The interest in these models is clearly motivated by the need to have models for switch mode de-de converters that are compatible with robust control design, which require a model structure consisting of a nominal model, and a norm-bounded modeling uncertainty. Therefore, a robust controller design under parameter uncertainties can be obtained instead of the deterministic approach widely used.