Comparative study of state space averaging and PWM with extra element theorem techniques for complex cascaded DC-DC Buck converter

Until now, most commonly used state space averaging and PWM techniques have been applied to different converter topologies and their advantages and disadvantages were stated. However, the superiority of an analytical technique was not justified based on a parametric comparison of these techniques for the same converter topology. Hence, in this paper, first time a comparative evaluation of two commonly used modelling techniques for fourth order converter is presented. The first approach makes use of a state-space averaging of the converter and is based on analytical manipulations using different state representations of the converter. The second approach is based on PWM switch modelling with an extra element theorem and consists of topological manipulations. The two modelling techniques are applied to the same complex cascaded DC-DC Buck converter and a transfer function is obtained. These techniques are compared for different features and the study concludes that state space modelling technique is systematic and less complicated than PWM switch modelling with an extra element theorem for a higher order converter.