Large-signal modeling of power conversion systems with independent inputs

Abstract

This paper presents an analytical modeling approach for switching power conversion systems with large-signal independent inputs, namely the control signal and supply voltage. These independent inputs consist of perturbations with large amplitudes and phase shifts. The key of the approach is to extend the classical Volterra functional analysis (VFS) to nonlinear systems with multiple independent inputs. Thus, the large-signal output response can be expressed as a summation of n-th order Volterra transfer functions. The approach not only models the higher harmonic frequency components, but also the subharmonic frequency components. An application example is used for exemplification, where the effects of phase differences in tones, enlarged control signal and reduced switching frequency have been investigated. The theoretical results obtained from the extended-VFS approach are verified using computer simulation. The approach is so general that it can be applied to various power conversion systems.