Analysis of switching network in PWM DC-DC converters in terms of averaged resistance and conductance

Equivalent circuit modelling of pulse-width modulated (PWM) converters requires averaging the on-state and forward resistances of transistor (M) and diode (D) over one switching period. Their values vary between a finite number (M-ON) and infinity (M-OFF) during the switching instants. Analytically, it becomes impossible to calculate the equivalent average resistance over one switching period. By determining their averaged conductances, a more intuitive model is derived for continuous conduction mode. Using reflective rules, these conductances are transferred to the inductor branch and an equivalent averaged conductance is derived and analysed.