Sliding regimes in pulse-width-modulation systems design

A design method is proposed for the specification of a variety of pulse-width-modulation (PWM) feedback controllers acting on plants described by nonlinear dynamical systems. It is first shown that an average model of the PWM-controlled system, derived by making an infinite sampling frequency assumption, is simply obtained by replacing the discontinuous control by a memoryless nonlinearity completely specified by the feedback duty ratio function. The average model captures the essential qualitative stability properties of the controlled system and, thus can be used to simplify the PWM controller design task considerably. The case of PWM regulators for linear plants can thus be systematically treated by traditional input-output design methods. Some examples are provided.<
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