Problems in analysis and design of switching regulators : I. Pole placement technique for DC-to-DC switching regulators. II. Transformer modelling. III. Cross-regulation of the two-output Cuk converter

Citation

Hsu, Shi-Ping (1980) Problems in analysis and design of switching regulators : I. Pole placement technique for DC-to-DC switching regulators. II. Transformer modelling. III. Cross-regulation of the two-output Cuk converter. Dissertation (Ph.D.), California Institute of Technology. doi:10.7907/GV8S-2J15. https://resolver.caltech.edu/CaltechETD:etd-10302006-100214

Abstract

Power Electronics is an interdisciplinary field which combines three of the major disciplines of electrical engineering--control, power and electronics. The three topics in this thesis arise from problems encountered in these fields. Part I is an application of modern control theory to the design of any dc-to-dc switching regulator. By feeding back all the state variables in a regulator, the system closed-loop poles can be placed anywhere desired on the s-plane. This is in contrast to the conventional single-loop design where the closed-loop poles are constrained on the root loci between the open loop poles and zeros. With this total-state feedback technique, the stability margins and transient responses of a switching regulator can be shaped as desired. Part II is a study of transformer modelling, which is important in the design of power processing circuits. The simple [pi]-model is used to model two-winding, three-winding and under some special cases, four-winding transformers. In the past, the parameters in the model were expressed in terms of the coupled-inductor coefficients L11, M12, L22 etc., while in this thesis, they are expressed in terms of the permeances which link the model directly to the physical layout of the windings. With this representation, the physical insight of the transformer is explicitly exposed in the model. Part III analyzes the cross-regulation problem of a two-output Cuk converter. The unique effect of the unequal discharge of the coupling capacitances on the cross-regulation of a Cuk converter is first discussed. It is pointed out that this effect can be made arbitrarily small by increasing the values of the capacitances. The parasitic effects such as leakage inductances, winding resistances and diode offset voltages are then included in the more general analysis. Quantitative results, which are useful in control and improvement of the cross-regulation, are given at the end.

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