Control-loop modeling of the controllable ZVS PWM forward converters using saturable magnetic cores

Employing a saturable core in the development of zero-voltage-switching (ZVS) technique has attracted widespread attention. However, these analyses are focused on the discussions of the uncontrollable ZVS pulsewidth modulation (PWM) converters. In this paper, the characteristics after the addition of the control circuits to the ZVS saturable-core PWM converters are considered. The small-signal models of the controllable ZVS saturable-core PWM converters are also proposed. Furthermore, a proper compensation strategy is offered to achieve a stable and satisfactory dynamic response. Self-excited ZVS PWM resonant regulators with the control scheme are eventually implemented to verify theoretical derivations.