Modeling of PWM boost converters for continuous and discontinuous inductor current modes

Abstract

Owing to the relatively more complicated nature of the boost converter with non-ideal elements and operating in continuous and discontinuous inductor current modes, a parsimonious large signal and small signal model for this converter, with and without feedback, has been lacking. In this work, a zero order hold equivalent discrete time model of the boost converter for computing its small signal frequency response and large signal and small signal closed loop behavior is developed and experimentally confirmed. The Newton-Raphson technique is used to accelerate the computation of the frequency response from the developed discrete time model. The use of the discrete time model in combination with the Newton-Raphson method in predicting the steady-state ripple behavior o f the converter is also studied. With the intention of future robust control studies on the boost converter in discontinuous inductor current mode, an initial evaluation of the frequency response predicted by the discrete time model at different operating points is presented.