Many years ago, Dr. Ćuk invented the Integrated Magnetics concept, demonstrating that input inductor, isolation transformer and output inductor can be placed on a common magnetic core if they have identical AC voltage waveforms for any operating duty ratio. In the TESLAconverter, the AC voltages of the input inductor and isolation transformer are always identical but the AC voltage on the output inductor becomes lower when duty ratio is less than 1. Nevertheless, the New Integrated Magnetics structure, called DC Transformer (since DC flux and air-gap are eliminated) was created.
The DC-flux in the new Integrated Magnetics structure is nearly eliminated or significantly reduced for any operating condition! The sum of the DC-fluxes created by the currents in the windings of the input inductor L1 and transformer T is equal to the DC flux created by the current in the output inductor L2 winding. Hence, the new Integrated Magnetic is designed in such a way that the above identical DC-fluxes are opposing each other and thus result in a mutual cancellation of the DC-flux. This enables the elimination or significant reduction of the air gap, while the zero ripple feature on both the input and output inductors at the nominal operating point is still preserved.
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