Abstract

Modelling of switching pulse width modulated phase-shifted full-bridge zero voltage converter is highly challenging due to several transitional stages involved in a complete switching cycle. The circuit averaging technique has been favored in the past three decades considering phase-shifted full-bridge converter as a buck-derived converter. This modelling approach requires several assumptions that include zero equivalent series resistance of output capacitor, zero leakage inductance and unity transformer turn ratio which results in a less accurate system dynamics. In this paper, a system identification approach is proposed for obtaining a more accurate model of phase-shifted full-bridge PWM switching converter using the input-output test data. The model parameter estimation is implemented in Simulink environment incorporating all circuit parasitic parameters and the resulting system’s frequency response shows a good agreement when compared with reported measured response.

Key words: System identification; Full-bridge converter; Zero voltage switching; Transfer function; Recursive least square.