Tapped inductor Boost with exploitation of the stray energy

Tapped inductor DC-to-DC converters are interesting circuits, the winding ratio of the two windings mounted on the same core change the voltage transformation ratio compared to the untapped inductor. The tapped inductor converters are especially useful, when high or low voltage transformation ratios have to be realized. The disadvantage of this concept is that the coupling between the two windings is not total and can be described by the stray or leakage inductance. This stray inductance leads to a high overvoltage at the active switch, and therefore also across other elements of the converter. After a short summery of the ideal tapped Boost converter, the design of an RCD snubber which limits the overvoltage is explained. To improve the efficiency of the converter two active snubber networks are treated, which feed the energy stored in the snubber capacitor into the input source or into the output circuit. Simulations are used to prove these considerations.