Small Signal Audio Susceptibility Analysis of Flyback Converter With Peak Current Mode Control

Özet

Small signal audio susceptibility of flyback converter with peak current mode control method is presented by utilizing pwm-switch model in Continuous Conduction Mode (CCM). The analysis provides input voltage to output voltage transfer function together with its zeros and poles in symbolic form. Numerator and denominator of the resultant transfer function are both 3rd order. While symbolic equations of zeros are provided as exact solutions, the symbolic equations of poles are provided as approximate solutions with the assumption that the real pole is well separated from the resonant frequency of the complex pole pair. Symbolically derived transfer function of flyback converter is validated on a numerical example by time domain PSIM simulations on a switching flyback converter model. The mathematical analysis and PSIM simulations of input voltage to output voltage transfer function of the converter agree very well up to frequencies below half the switching frequency.