Critical Current Control (C3) and Modelling of a Buck Based LED Driver with Power Factor Correction

Buck converter has a good aptitude for LED driver application. Here a new technique introduced to control and model a buck converter in the closed loop condition using Lagrange equation. To improve the final model accuracy, parasitic elements of the converter are taken into account. The main advantage of this method is its novelty and simple implementation. Also, the converter power factor has improved under critical current control (C3) technique. Frequency response and step response of the small signal model are derived and analysed. The theoretical predictions are tested and validated by means of PSIM software. Finally, precise agreement between the proposed model and the simulation results has obtained.

---

W artykule analizowano zastosowanie przekształtnika typu buck do zasilania diod LED. Zaproponowano nowy układ z uwzględnieniem elementów zakłócających pracę. Zastosowano sterowanie prądem krytycznym dla poprawy jakości pracy przekształtnika. Analizowano właściwości dynamiczne układu.