Patent ID: 7817452
Filing Date: 2010-10-19
Classification: H02M,Y02B

Abstract:
1. A phase shifted H-bridge resonant converter with symmetrical currents comprising: first and second pairs of series connected controllable switching devices, the first and second pairs of said switching devices parallel connected across a first capacitor and coupled to a DC power source, each of said switching devices comprising; an IGBT with internal anti-parallel diode, turn off network with turn off diode in parallel with a turn off resistor, in series with a turn off capacitor connected across each of said switching devices; a low mutually coupled inductor with first and second windings, each winding with a first terminal and a second terminal, wherein said second terminal of said first winding is connected to said first terminal of said second winding to form a center tap terminal; an AC load comprising a second capacitor in series with a resistor, wherein said second capacitor is connected to said first terminal of said first winding of said low mutually coupled inductor, and said resistor is connected to said second terminal of said second winding of said low mutually coupled inductor; first and second DC blocking capacitors, said first DC blocking capacitor connected between said first terminal of said first winding of said low mutually coupled inductor and a common terminal of said first pair of switching devices; and said second DC blocking capacitor connected between said second terminal of said second winding of said low mutually coupled inductor and a common terminal of said second pair switching devices; a transformer with first and second windings, each winding with a first terminal and a second terminal, said first terminal of said first winding connected to said center tap terminal of said low mutually coupled inductor, said second terminal of said first winding connected to first and second resonant capacitors connected in parallel, and coupled to the DC power source ground; and an output circuit comprising said second winding of said transformer connected to a full wave bridge rectifier, filter inductor, filter capacitor and a load resistor, wherein said low mutually coupled inductor, said AC load, and said first and second resonant capacitors form a resonant tank circuit for producing said symmetrical currents within said first and second pairs of switching devices and said transformer.