Modeling conduction lossSEPIC example

MOSFET Ron, diode VD

Averaged terminal voltages of switch network, including conduction losses:

Averaging the terminal currents

Elimination of intermediate variables

From previous slides:

Eliminate inductor currents and capacitor voltages, which are external to switch network:

Construct equivalent circuit:

Spice library model CCM2

Insert model into SEPICSimulation of conversion ratio and efficiency

Simulation modelBuck-boost with conduction loss

Buck-boost converter Averaged switch model

Transient analysis example