Floating double boost converter

The combination of two converters to a dual floating converter is an interesting concept. Here a positive output double floating boost converter is treated. The concept is explained step by step with the help of signal drawings and basic calculations. The fourth order model is derived for large and small signals, idealized components, and can be used to study the converter when it is not built symmetrically. A simpler model of second order is sufficient, when the two converter stages have nearly the same component values. The position of the zeroes and the poles are treated. The turn-on and the soft-start of the converter are also studied. With an additional stage the inrush into the converter can be avoided and the converter can be protected from short-circuit, no load, overheating, and overload. Simulations with the help of LTSpice are presented to validate the considerations. The influence of the parasitic capacitors to ground are studied. Interesting modifications of the converter are shown. Experimental results of a small laboratory converter are presented.