Zero-voltage switching power converter with ripple current cancellation

In a converter circuit, including:

• first and second power switches operated at unequal conduction intervals;
• a power transformer having a primary winding connected to the first and second power switches and a secondary winding;
• a rectifier circuit;
• a ripple cancellation circuit interconnecting the secondary winding to the rectifier circuit and including;
• first and second inductors having inductance values having a ratio equal to a ratio of the unequal conduction intervals, a third inductor connected to the first and second inductors in delta connection, and the third inductor shunting the secondary winding.

In a converter circuit, including:

• first and second power switches operated at unequal conduction intervals;
• a power transformer having a primary winding connected to the first and second power switches and a secondary winding;
• a rectifier circuit;
• a ripple cancellation circuit interconnecting the secondary winding to the rectifier circuit and including;
• first and second inductors having inductance values having a ratio equal to a ratio of the unequal conduction intervals and a third inductor connected to the first and second inductors in a delta connection, and the third inductor shunting the secondary winding;
• and
• the first, second and third inductors being wound on a ferrite core having three parallel branches.

A bridge type power converter in which conduction/non-conduction transitions of its power switching transistors occur at zero voltage,

• comprising:
• an input circuit for accepting a source of energy;
• first and second power switching transistors connected in series circuit and the series circuit connected in shunt with the input circuit;
• a first conducting interval of the first power switching transistor being substantially less in duration than a second conducting interval of the second power switching transistor,
• a power transformer having a primary winding connected to a common node joining the first and second power switching transistors, and a secondary winding;
• a rectifier circuit connected to the secondary winding for rectifying the voltage output of the secondary winding;
• an output circuit for coupling the rectified voltage of the rectifier circuit to a load to be energized;
• magnetic current ripple cancellation circuitry, including:
• first, second and third inductance devices being connected in a loop of three inductance devices with the third inductance device shunting the secondary winding;
• the first and second inductance devices having inductance values in a ratio equal to a ratio of the first and second conducting intervals;
• the first and second inductance devices being connected between the secondary winding and the rectifier circuit;
• and
• the first, second and third inductance devices being wound of a ferrite core having three parallel branches.