A quasi-resonant zero-current-switching buck PWM converter using a nonlinear resonant inductor

This paper shows a lossless commutation cell that uses a nonlinear resonant inductor. The principle of the nonlinear resonant inductor is applied to a QRC-ZCS-PWM buck converter with the objective of reducing the peak current in the main switch, maintaining the ZCS characteristics of the QRC-ZCS-PWM buck converter. This is achieved by unsaturating the core of the nonlinear resonant inductor limiting its peak value. The proposed converter has the following advantages: lower current stress in the main switch; the current peak value stays almost fixed with the load increase; it operates with fixed frequency; and it has lossless commutation.