Determination and Relativity of the Leakage Inductance of Push-pull Transformers

The electronic transformer model is a multi-parameter system. The parameters vary along with the changes of V, dV/dt, i, di/dt, thetas and dthetas/dt. However, conventional methods are in essence single-parameter direct measurement. Detailed analysis on magnetic flux of push-pull transformers is presented with turn-on and turn-off status of power switching devices considered. The specific methods associated with the direction of the power flow to determine leakage inductances are proposed in this paper: the mutual leakage inductance between primary windings and secondary windings should be calculated through step response under rated voltage and full-load condition; while the mutual leakage inductance of two primary windings should be calculated through spike voltage when switching the maximum current. Validity of these methods is proved by the satisfied outcomes of the snubber circuit and the lowpass filter designed by the above results respectively