Analysis of IMC method applied to output current control on DC/DC buck converter - a power led switching on application

In the last years, the advances on power electronics technology have led to many switching converters design, whose switching on-off property is more efficient than traditional rheostat based converters, which power losses are higher. Therefore, the switching converters are present at many devices, like photovoltaic systems, no-break circuits and DC settable voltage sources. A typical DC/DC converter transforms voltage and current between constant levels. Hence, when the application needs an output voltage level lower than input voltage level, it is common to design a step down, or a buck, DC/DC converter; it is the case of power LED switching on. More specifically, light emitter diode (LED) has become increasingly common in power applications, like lighting sources, because its high efficiency characteristic is economically advantageous. However, the power LED, in general, needs an accurate current level supply, because the diode non-linear resistance may lead it to overheat by an overcurrent, damaging it. Thereby, this paper presents the study of the internal model control (IMC) design, applied on the buck converter´s output current control, used for supply a power LED, and it analyses the performance parameters comparing it with PI controller used at the same application.