A Non-Ideal SEPIC DCM Modeling for LED Lighting Applications

The life cycle of the Light Emitting Diodes (LEDs) requires a robust and reliable driver since the components may have influence in the lifetime of the lighting system, which is an undesirable situation. In addition, LED strings can be sold for different loads possibilities. This requires the converter components to be designed in a generalized and oversized way. As a consequence, sizable components lead to increased losses mainly in the semiconductors. In the last ones, the forward voltage drops and resistances typically increase relatively to their voltage blocking capacity. This work presents a steady state and dynamic modeling of a SEPIC converter operating in Discontinuous Conduction Mode (DCM) for LED lighting applications, considering non-idealities. Simulations and Hardware-in-the-Loop results are presented to validate the derived dynamic and steady-state models as well as to present a DCM PFC SEPIC rectifier application driving a 72 V-100 W LED lamp from a 220 V-60 Hz grid.