A method for modelling switching-converter power stages is developed, whose starting point is the unified state-space representation of the switched networks and whose end result is either a complete state-space description or its equivalent small-signal low<-f requency linear circuit model.A new canonical circuit model is proposed, whose fixed topology contains all the essential inputr-output and control properties of any dc-todc switching converter, regardless of its detailed configuration, and by which different converters can be characterized in the form of a table con veniently stored in a computer data bank to pro vide a useful tool for computer aided design and optimization. The new canonical circuit model predicts that, in general;switching action intro duces both zeros and poles into the duty ratio to output transfer function in addition to those from the effective filter network.

A method for modelling switching-converter power stages is developed, whose starting point is the unified state-space representation of the switched networks and whose end result is either a complete state-space description or its equivalent small-signal low<-f requency linear circuit model. A new canonical circuit model is proposed, whose fixed topology contains all the essential inputr-output and control properties of any dc-todc switching converter, regardless of its detailed configuration, and by which different converters can be characterized in the form of a table con veniently stored in a computer data bank to pro vide a useful tool for computer aided design and optimization. The new canonical circuit model predicts that, in general;switching action intro duces both zeros and poles into the duty ratio to output transfer function in addition to those from the effective filter network.

Abstract-In dc-to-dc conversion applications that require a large range of input andlor output voltages, conventional PWM converter topologies must operate at extremely low duty ratios, which limits the operation to lower switching frequencies because of the minimum ONtime of the transistor switch. This is eliminated in a new class of singletransistor PWM converters featuring voltage conversion ratios with quadratic dependence on duty ratio. Practical circuit examples operating at 0.5 MHz are described.

A new large-signal nonlinear control technique is proposed to control the duty-ratio d of a switch such that in each cycle the average value of a switched variable of the switching converter is exactly equal to or proportional to the control reference in the steady-state or in a transient. One-Cycle Control rejects power source perturbations in one switching cycle; the average value of the switched variable follows the dynamic reference in one switching cycle; and the controller corrects switching errors in one switching cycle. There is no steady-state error nor dynamic error between the control reference and the average value of the switched variable. Experiments with a constant frequency buck converter have demonstrated the robustness of the control method and verified the theoretical predictions. This new control method is very general and applicable to all types of pulse-width-modulated, resonant-based, or soft-switched switching converters for either voltage or current control in continuous or discontinuous conduction mode. Furthermore, it can be used to control any physical variable or abstract signal that is in the form of a switched variable or can be converted to the form of a switched variable.

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