A refined nonlinear averaged model for constant frequency current mode controlled PWM converters

A refined, duo-mode model for current programmed buck power converters is presented. The refined model uses a form of the current mode control law which is truly invariant with respect to operating conditions. That is, it is valid for both transient and steady-state operating conditions regardless of the converter operating mode, which could be either continuous conduction mode (CCM) or discontinuous conduction mode (DCM). The large-signal transient response predicted using the refined average model is shown to be virtually indistinguishable, in an average sense, from that predicted using a pulse-by-pulse simulation. The refined model is shown to exhibit improved high-frequency accuracy in both time and frequency domains. The model has been implemented in SPICE 2G6 and runs with default analysis options