Average simulation of PWM converters by direct implementation of behavioural relationships

Average modelling of PWM converters is reexamined in the light of the behavioural-dependent sources now included in modern versions of electronic circuit simulators. A topology-independent behavioural model is developed to emulate the operation of PWM converters in voltage and current modes, for continuous and discontinuous inductor current cases. It is shown that the operation of the switching part involves, in general, three behavioural blocks: the generic switched inductor model, the duty cycle generator and the inductor current generator. Explicit expressions and equivalent circuits are developed for all possible modes of operation and a PSpice (MicroSim Inc., Irvine, CA)netlist template is appended.