Circuit and method for achieving zero ripple current in the output of a converter

Claim 2

A power converter, comprising: a transformer for receiving bipolar electrical input power from a power source, said power substantially free of dead time; and a hybridge rectifier coupled to said transformer and including first and second output inductors of independently selectable, differing inductance, said hybridge rectifier receiving said input power from said transformer and rectifying said input power to produce an output power substantially free of ripple current at a predetermined duty cycle operating point of said converter, said first and second output inductors being of independently selectable, differing inductance thereby to allow said predetermined duty cycle operating point to be adjustable.

Claim 3

The converter as recited in claim 1 wherein said power source is selected from the group consisting of: an active clamp circuit, and a ZVS half bridge circuit.

Claim 4

The converter as recited in claim 1 wherein a secondary winding of said transformer is free of a center tap.

Claim 5

The converter as recited in claim 1 wherein said rectifier further comprises first and second switches, said first and second switches selected from the group consisting of: diodes, and metal oxide semiconductor field effect transistors (MOSFETs).

Claim 6

The converter as recited in claim 1 wherein an inductance of said first output inductor is related to an inductance of said second output inductor by the equation: L.sub.out1 =(L.sub.out2 *(1-D))/D where: L out1 is said inductance of said first output inductor, L out2 is said inductance of said second output inductor, and D is said predetermined duty cycle operating point of said converter.

Claim 7

The converter as recited in claim 1 wherein said predetermined duty cycle operating point of said converter is other than 50%.

Claim 8

The converter as recited in claim 1 wherein said rectifier further comprises an output capacitor coupled to said first and second output inductors to reduce said ripple current when said converter is operating at other than said predetermined duty cycle operating point.

Claim 11

The method as recited in claim 8 further comprising the step of generating said input power in said power source, said power source selected from the group consisting of: an active clamp circuit, and a ZVS half bridge circuit.

Claim 12

The method as recited in claim 8 wherein a secondary winding of said transformer is free of a center tap.

Claim 13

The method as recited in claim 8 wherein said rectifier further comprises first and second switches, said step of receiving further comprising the step of rectifying said input power in said first and second switches, said first and second switches selected from the group consisting of: diodes, and metal oxide semiconductor field effect transistors (MOSFETs).

Claim 14

The method as recited in claim 8 further comprising the step of selecting an inductance of said first output inductor and an inductance of said second output inductor, said inductance of said first output inductor related to said inductance of said second output inductor by the equation: L.sub.out1 =(L.sub.out2 *(1-D))/D where L out1 is said inductance of said first output inductor, L out2 is said inductance of said second output inductor, and D is said predetermined duty cycle operating point of said converter.

Claim 15

The method as recited in claim 8 wherein said predetermined duty cycle operating point of said converter is other than 50%.

Claim 16

The method as recited in claim 8 wherein said rectifier further comprises an output capacitor coupled to said first and second output inductors, said method further comprising the step of reducing said ripple current with said output capacitor when said converter is operating at other than said predetermined duty cycle operating point.

Claim 17

An electrical system, comprising: a power conversion stage including power switching devices for receiving electrical power and producing therefrom bipolar electrical input power substantially free of dead time; a transformer having a primary winding coupled to said power conversion stage and having two taps on a secondary winding thereof, said primary winding receiving said bipolar electrical input power from said power conversion stage; a hybridge rectifier coupled between said two taps and including first and second output inductors of independently selectable, differing inductance, said hybridge rectifier receiving said input power from said transformer via said two taps and rectifying said input power to produce an output power substantially free of ripple current at a predetermined duty cycle operating point of said converter, said first and second output inductors being of independently selectable, differing inductance thereby to allow said predetermined duty cycle operating point to be adjustable; and an electrical load, coupled to said rectifier, for receiving and dissipating said output power.

Claim 18

An electrical system, comprising: a power conversion stage including power switching devices for receiving electrical power and producing therefrom bipolar electrical input power substantially free of dead time; a transformer having a primary winding coupled to said power conversion stage and having two taps on a secondary winding thereof, said primary winding receiving said bipolar electrical input power from said power conversion stage; a hybridge rectifier coupled between said two taps and including first and second output inductors of independently selectable, differing inductance, said hybridge rectifier receiving said input power from said transformer via said two taps and rectifying said input power to produce an output power substantially free of ripple current at a predetermined duty cycle operating point of said converter, said first and second output inductors being of independently selectable, differing inductance thereby to allow said predetermined duty cycle operating point to be adjustable; and an electrical load, coupled to said rectifier, for receiving and dissipating said output power.

Claim 19

The system as recited in claim 15 wherein said power conversion stage is selected from the group consisting of: an active clamp circuit, and a ZVS half bridge circuit.

Claim 20

The system as recited in claim 15 wherein said rectifier further comprises first and second switches, said first and second switches selected from the group consisting of: diodes, and metal oxide semiconductor field effect transistors (MOSFETs).

Claim 21

The system as recited in claim 15 wherein an inductance of said first output inductor is related to an inductance of said second output inductor by the equation: L.sub.out1 =(L.sub.out2 *(1-D))D where: L out1 is said inductance of said first output inductor, L out2 is said inductance of said second output inductor, and D is said predetermined duty cycle operating point of said converter.

Claim 22

The system as recited in claim 15 wherein said predetermined duty cycle operating point of said converter is other than 50%.

Claim 23

The system as recited in claim 15 wherein said rectifier further comprises an output capacitor coupled between said first and second output inductors and said electrical load to reduce said ripple current when said converter is operating at other than said predetermined duty cycle operating point.