Load-resistor-affected dynamic models in control design of switched-mode converters

Abstract

<p>The application of a resistor as a load of the pulse-width-modulated DC-DC converters has dominated the dynamic modelling since the development of the modelling methods in early 1970s. In 1990s, the research in the source and load interactions was very active providing valuable information to justify the necessity to develop unterminated dynamic models for characterising the dynamics of the converters. The small-signal modelling can be performed always by using the ideal load, which is determined by the output-terminal variable to be kept constant, regardless of whether the actual open-loop converter can operate or not with the ideal load. This paper will review the feasibility of using the load-resistor-affected models in control design of switched mode converters. The best strategy is always to use unterminated models, which can be used to obtain different load-impedance-affected models if needed. A buck converter is used as the source of information.</p>