A new concept of a DC-DC converter with galvanic isolation is proposed in this paper. The converter belongs to the class E resonant converters controlled by pulse width modulation via frequency regulation (PWM FM). Due to the possibility of operation in the boost and buck modes, the converter is characterized by a high range of voltage gain regulation. The principle of converter operation described by mathematical equations is presented. The theoretical investigations are confirmed by p-spice model simulations and the measurement of an experimental model of 1kW laboratory prototype.
 P. Antosiewicz and M.P. Kaźmierkowski, “Virtual - flux- based predictive direct power control of AC/DC converters with online inductance estimation”, IEEE Trans. Ind. Electron. 55, 4381-4389 (2008).
 M. Malinowski, S. Styński, W. Kołomyjski, and M.P. Kaźmierkowski, “Control of three level PWM converter applied to variable - speed - turbines”, IEEE Trans. Ind. Electron. 56, 69-77 (2009).
 J. Mordewicz and M.P. Kaźmierkowski, “Contactless energy system with FPGA - controlled resonant converter”, IEEE Trans. Ind. Electron. 57, 3181-3190 (2010).
 M.P. Kaźmierkowski, M. Jasiński, and G. Wrona, “DSP-basedcontrol of grid - connected power converters operating under grid distortions”, IEEE. Ind. Informatics IEEE Trans. 7, 204-2011 (2011).
 E.H. Kim and B.H. Kwon, “High step-up resonant push-pull converter with high efficiency” Power Electronics IET 2, 79-89 (2009).
 M. Nymand and M.A.E. Andersen, “A new approach to high efficiency in isolated boost converters for high power low-voltage fuel cell applications”, Power Electronic and Motion Control Conf. 13thEPE-PEMC 2008 1, 127-131 (2008).
 R.J. Wai and R.Y. Duan, “High efficiency DC/DC converter with voltage gain electric power applications”, IEEE Proc. 152, 793-802 (2005).
 Q. Zhao and F.C. Lee, “High- efficiency, high step-up DC-DC converters”, IEEE Trans. on Power Electron. 18, 65-73 (2003).
 P. Klimczak and S. Munk-Nilsen, “Comparative study on paralleled vs. scaled DC-DC converters in high voltage gain applications”, Power electronic and Motion Control Conf. EPEPEMC 2008 13th 1, 108-113 (2008).
 G.V. Torico-Bascope, R.P. Torico-Bascope, D.S. Oliviera, F.L.M. Antunes, S.V. Araujo, and C.G.C. Branco “A generalized high voltage gain boost converter based on three-state switching cell”, 32nd Annual Conf. IEEE Industrial Electronics Society IECoN’06 1, 1927-1932 (2006).
 A. Tomaszuk and A. Krupa, “High efficiency high step-up DCDC converters review“, Bull. Pol. Ac.: Tech. 59 (4), 475-483 (2011).
 S. Jalbrzykowski and T. Citko “Current-fed resonant full-bridge boost DC/AC/DC converter”, IEEE. Trans. on Ind. Electron. 55 (3), 1198-1205 (2008).
 S. Jalbrzykowski and T. Citko, “A bidirectional DC-DC converter for renewable energy systems”, Bull. Pol. Ac.: Tech. 61 (2), 363-368. (2009).
 M. Mikołajewski, ”A self-oscillating H.F power generator with a Class E resonant amplifier”, Bull. Pol. Ac.: Tech. 61 (2), 527-534 (2013).Bull.