Resonant LLC converter with a multi-leg transformer with gapped center leg

A power conversion device using a magnetic component assembly,

• wherein the magnetic component assembly comprises:
• a winding coupled body formed of n number of windings magnetically coupled with each other, n being an integer greater than 1, one end of each winding being connected in series to a DC voltage source via a DC reactor, other ends of the windings being connected to nonlinear elements which become conductive at timings different from each other;
• and
• a multi-leg core formed of n number of side legs and a center leg having a gap portion, wherein
• the n number of windings of the winding coupled body are wound around the respective side legs of the multi-leg core, a winding of the DC reactor is wound around the center leg of the multi-leg core, and winding directions of the windings of the winding coupled body and the winding of the DC reactor are set so that magnetic fluxes generated by DC currents flowing through the windings of the winding coupled body and the winding of the DC reactor merge in the same direction at the center leg of the multi-leg core, whereby the DC reactor and the winding coupled body are integrated using the multi-leg core,
• wherein the power conversion device converts AC voltage of AC terminals to DC voltage and outputting the DC voltage to DC terminals of the DC voltage source, and the power conversion device comprises:
• a transformer having a primary-side winding connected to the AC terminals and a secondary-side winding which is the winding coupled body and which is connected to the DC terminals, via rectification elements as the nonlinear elements, and the DC reactor, wherein
• the secondary-side winding of the transformer is composed of a first winding and a second winding having respective ends connected in series to each other at an intermediate point, and other ends connected to the intermediate point via the rectification elements, the DC reactor, and the DC terminals,
• the DC reactor is composed of a third winding,
• the primary-side winding of the transformer is composed of a fourth winding and a fifth winding having respective ends connected in series to each other and other ends connected to the AC terminals,
• the power conversion device comprises a three-leg core in which the number n for the multi-leg core is 2 so that the three-leg core is formed of two side legs and a center leg having a gap portion, the first winding and the second winding being wound around the respective side legs, the third winding being wound around the center leg, the fourth winding and the fifth winding being wound around the respective side legs, wherein
• winding directions of the first winding, the second winding, and the third winding are set so that magnetic fluxes generated by DC currents flowing through the first winding, the second winding, and the third winding merge in the same direction at the center leg, and winding directions of the fourth winding and the fifth winding are set so that magnetic fluxes generated by AC currents flowing through the fourth winding and the fifth winding cancel each other at the center leg, whereby the transformer and the DC reactor are integrated using the three-leg core,
• wherein the power conversion device further comprises a filter capacitor in parallel with the DC terminals, wherein
• a leakage inductance of the transformer and the DC reactor form a filter reactor resonating with the filter capacitor.