# US 6,782,513 B1 · High power factor integrated controlled ferroresonant constant current source

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- Number: US 6,782,513 B1
- Document ID: US6782513B1
- Status: Granted
- Kind: B1
- Application number: 10/076,983
- Filed: 2002-02-15
- Granted: 2004-08-24
- Earliest claimed: 2002-02-15
- Assignees: Shape Electronics, Inc.
- Inventors: Raymond G. Janik
- Web page: https://patentgrep.com/patent/US6782513B1

## CPC

- H01F 29/14: with variable magnetic bias
- G06F 30/00: Computer-aided design [CAD]
- G06F 2119/06: Power analysis or power optimisation
- H01F: MAGNETS; INDUCTANCES; TRANSFORMERS; SELECTION OF MATERIALS FOR THEIR MAGNETIC PROPERTIES
- G06F: ELECTRIC DIGITAL DATA PROCESSING (computer systems based on specific computational models G06N)

## Abstract

A method of designing a high power factor integrated ferroresonant constant current source includes the steps of providing an input coil disposed about a ferromagnetic core and to be coupled to an AC voltage source. An output coil is to be coupled to a load. A control coil is coupled to a switch for regulating current output of the constant current source. A first capacitor coil is inductively coupled to the output coil and coupled to a capacitor to provide a first resonant sub-circuit having maximum gain, and a second capacitor coil is inductively coupled to the control coil and coupled to a capacitor to provide a second resonant sub-circuit to control resonant gain. A flux density (BPRI) is selected for a portion of the core around the input coils that is substantially lower than the flux density BCAP of a portion of the core around the capacitor coils.

## Claims

### Claim 1

A method of designing a high power factor integrated ferroresonant constant current source comprising the steps of:
providing an input coil disposed about a ferromagnetic core and to be coupled to an AC voltage source;
providing an output coil disposed about the core and to be coupled to a load;
providing a control coil disposed about the core and coupled to a switch for regulating current output of the constant current source;
providing a first capacitor coil disposed about the core and inductively coupled to the output coil and coupled to a capacitor to provide a first resonant sub-circuit having maximum gain, and a second capacitor coil disposed about the core and inductively coupled to the control coil and coupled to a capacitor to provide a second resonant sub-circuit to control resonant gain; and
selecting a flux density (BPRI) of a portion of the core around the input coil that is substantially lower than flux density BCAP of a portion of the core around the capacitor coils.

### Claim 2 (depends on 1)

A method as defined in claim 1, wherein BCAP is about 14 kG to about 15 kG.

### Claim 3 (depends on 1)

A method as defined in claim 1, further including the step of selecting a leakage reactance XS satisfying the following mathematical expression: X S ≤ R 2 + X O 2 RA ,
where R is resistance of all of the windings, XO is reactance of an output inductor magnetically coupled to a resonant capacitor, and A is a capacitor voltage gain.

### Claim 4 (depends on 1)

A method as defined in claim 1, further including the step of selecting the value of XO and BCAP to limit an output current Io to a predetermined maximum value IO MAX where I OMAX = V CMAX X O 2 + R 2
and where BCAP SAT∝VC MAX wherein XO is reactance of an output inductor magnetically coupled to resonant capacitor, R is resistance of all windings, BCAP SAT is BCAP at saturation point and VC MAX is capacitor voltage BCAP SAT.

### Claim 5 (depends on 4)

A method as defined in claim 4, further including the step of selecting turns ratio (n) of the output coil to the capacitor coils to set an open circuit, output voltage VO OC to a predetermined value: where V OOC = n ⁢ ⁢ B CAPSAT B CAP ⁢ V C
wherein VC is capacitor voltage.

### Claim 6

A method of designing a high power factor integrated ferroresonant constant current source comprising the steps of:
providing an input coil disposed about a ferromagnetic core and to be coupled to an AC voltage source;
providing an output coil disposed about the core and to be coupled to a load;
providing a control coil disposed about the core and coupled to a switch for regulating current output of the constant current source;
providing a first capacitor coil disposed about the core and inductively coupled to the output coil and coupled to a capacitor to provide a first resonant sub-circuit having maximum gain, and a second capacitor coil disposed about the core and inductively coupled to the control coil and coupled to a capacitor to provide a second resonant sub-circuit to control resonant gain; and
selecting a flux density (BPRI) of a portion of the core around the input coil that is about one half flux density BCAP of a portion of the core around the capacitor coils.

### Claim 7 (depends on 6)

A method as defined in claim 6, wherein BCAP is about 14 kG to about 15 kG.

### Claim 8 (depends on 6)

A method as defined in claim 6, further including the step of selecting the value of XO and BCAP to limit an output current Io to a predetermined maximum value IO MAX where I OMAX = V CMAX X O 2 + R 2
and where BCAP SAT∝VC MAX wherein XO is reactance of an output inductor magnetically coupled to resonant capacitor, R is resistance of all windings, BCAP SAT is BCAP at saturation point and VC MAX is capacitor voltage BCAP SAT.

### Claim 9 (depends on 8)

A method as defined in claim 8, further including the step of selecting turns ratio (n) of the output coil to the capacitor coils to set an open circuit, output voltage VO OC to a predetermined value: where V OOC = n ⁢ ⁢ B CAPSAT B CAP ⁢ ⁢ V C
wherein VC is capacitor voltage.

### Claim 10

A method of designing a high power factor integrated ferroresonant constant current source comprising the steps of:
providing an input coil disposed about a ferromagnetic core and to be coupled to an AC voltage source;
providing an output coil disposed about the core and to be coupled to a load;
providing a control coil disposed about the core and coupled to a switch for regulating current output of the constant current source;
providing a first capacitor coil disposed about the core and inductively coupled to the output coil and coupled to a capacitor to provide a first resonant sub-circuit having maximum gain, and a second capacitor coil disposed about the core and inductively coupled to the control coil and coupled to a capacitor to provide a second resonant sub-circuit to control resonant gain;
selecting a flux density (BPRI) of a portion of the core around the input coil that is about one half flux density BCAP of a portion of the core around the capacitor coils; and
selecting a leakage reactance XS satisfying the following mathematical expression: X S ≤ R 2 + X O 2 RA ,
where R is resistance of all of the windings, XO is reactance of an output inductor magnetically coupled to a resonant capacitor, and A is a capacitor voltage gain.

### Claim 11 (depends on 10)

A method as defined in claim 10, wherein BCAP is about 14 kG to about 15 kG.

### Claim 12 (depends on 10)

A method as defined in claim 10, further including the step of selecting the value of XO and BCAP to limit an output current Io to a predetermined maximum value IO MAX where I OMAX = V CMAX X O 2 + R 2
and where BCAP SAT∝VC MAX wherein BCAP SAT is BCAP at saturation point and VC MAX is a capacitor voltage at BCAP SAT.

### Claim 13 (depends on 12)

A method as defined in claim 12, further including the step of selecting turns ratio (n) of the output coil to the capacitor coils to set an open circuit, output voltage VO OC to a predetermined value: where V OOC = n ⁢ ⁢ B CAPSAT B CAP ⁢ ⁢ V C
wherein VC is capacitor voltage.