This work aims to achieve load current-dependent variable leakage inductance profile in a high frequency (HF) transformer using integrated magnetics design, which is simple, scalable, avoids airgap introduced in the main magnetic path, offers nearly decoupled control of the magnetizing and leakage inductance, and eliminates any additional bias/control windings and moving/changeover mechanisms, thereby ameliorating the limitations of existing methods reported in literature. First, the synthesis of proposed methodology is discussed; this is followed by derivation of a magnetic equivalent circuit encompassing the load-current dependent variable leakage inductance characteristics. Finally, the operating principle is verified using FEM simulation results based on a 7.2 kW, 360/360 V, 500 kHz, ferrite core transformer modeled in FEMM. Compared to conventional design, for the same interwinding isolation thickness, using the proposed scheme the integrated leakage inductance increases from 9.95 to 13.7 µH, corresponding to a 37.7% change, while the load/coil current decreases from full load to 10% of its rated value.
