# US 11,114,932 B1 · Method and apparatus for reduction of ripple current > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 11,114,932 B1 - Document ID: US11114932B1 - Status: Granted - Kind: B1 - Application number: 16/904,684 - Filed: 2020-06-18 - Granted: 2021-09-07 - Earliest claimed: 2020-06-18 - Assignees: GE Aviation Systems LLC - Applicants: Ge Aviation Systems LLC - Inventors: Slobodan Gataric; Predrag Hadzibabic - Web page: https://patentgrep.com/patent/US11114932B1 ## CPC - H02M 1/143: {using compensating arrangements (for reducing noise from the supply in transmission systems H04B15/005)} - H02M 1/0064: {Magnetic structures combining different functions, e.g. storage, filtering or transformation} - H02M 1/126: {using passive filters} - H02M: APPARATUS FOR CONVERSION BETWEEN AC AND AC, BETWEEN AC AND DC, OR BETWEEN DC AND DC, AND FOR USE WITH MAINS OR SIMILAR POWER SUPPLY SYSTEMS; CONVERSION OF DC OR AC INPUT POWER INTO SURGE OUTPUT POWER; CONTROL OR REGULATION THEREOF (transformers H01F; dynamo-electric converters H02K47/00; controlling transformers, reactors or choke coils, control or regulation of electric motors, generators or dynamo-electric converters H02P) ## Abstract A ripple current reduction circuit is disclosed. The circuit includes a set of first coupled inductors, each comprising a primary winding configured to receive at a first end a respective phase voltage, and a secondary winding. The circuit also includes a set of second coupled inductors and a set of first capacitors, each first capacitor having an upstream end and a downstream end, wherein the set of first capacitors are coupled together at the downstream end to define a first node. The circuit further includes a set of auxiliary circuits each corresponding to a respective phase voltage, and coupled between the second end of the primary winding of a respective first inductor and the first node, wherein each auxiliary circuit comprises a respective second coupled inductor, a respective first capacitor, and the secondary winding of a respective first coupled inductor coupled in series. ## Claims ### Claim 1 A ripple current reduction circuit couplable to a polyphase AC voltage source having a neutral line, the circuit comprising: a set of first coupled inductors being inductively coupled on a first common core, each first coupled inductor comprising a respective primary winding having a first end and a second end, and configured to receive at the first end a respective phase voltage from the polyphase AC voltage source, and a secondary winding; a set of second coupled inductors being inductively coupled on a second common core; a set of first capacitors; and a set of auxiliary circuits, each auxiliary circuit corresponding to a respective phase voltage and coupled between the second end of each primary winding of a respective first inductor and the neutral line, wherein each auxiliary circuit comprises a respective second coupled inductor of the set of second coupled inductors, a respective first capacitor of the set of first capacitors, and the secondary winding of a respective first coupled inductor electrically coupled in series. ### Claim 2 (depends on 1) The ripple reduction circuit of claim 1, further comprising a set of second capacitors at an output of the ripple reduction circuit, each second capacitor coupled between the second end of the primary winding of a respective first inductor and the neutral line. ### Claim 3 (depends on 1) The ripple reduction circuit of claim 1, wherein each second capacitor is coupled to receive a respective phase voltage. ### Claim 4 (depends on 3) The ripple reduction circuit of claim 3, wherein each second capacitor is coupled electrically in parallel with a respective auxiliary circuit of the set of auxiliary circuits. ### Claim 5 (depends on 1) The ripple reduction circuit of claim 1, wherein each auxiliary circuit of the set of auxiliary circuits corresponds to a respective phase voltage. ### Claim 6 (depends on 1) The ripple reduction circuit of claim 1, further comprising a set of third coupled inductors, being magnetically coupled on a third common core, each third coupled inductor of the third set of coupled inductors being electrically coupled in series with the primary winding of a respective first coupled inductor of the set of first coupled inductors at an input of the ripple reduction circuit. ### Claim 7 (depends on 1) The ripple reduction circuit of claim 1, wherein the polyphase AC voltage source comprises a low frequency modulated high frequency AC voltage source. ### Claim 8 (depends on 1) The ripple reduction circuit of claim 1, wherein the polyphase AC voltage source is a 3-phase AC voltage source. ### Claim 9 A ripple current reduction circuit couplable to a polyphase AC voltage source, the ripple current reduction circuit comprising: a set of first coupled inductors being inductively coupled on a first common core, each first coupled inductor comprising a respective primary winding having a first end and a second end, and configured to receive at the respective first end a respective phase voltage from the polyphase AC voltage source, and a secondary winding; a set of second coupled inductors being inductively coupled on a second common core; a set of first capacitors, each first capacitor having a first upstream end and a first downstream end, wherein the set of first capacitors are coupled together at the first downstream end to define a first node; and a set of auxiliary circuits, each auxiliary circuit corresponding to a respective phase voltage and coupled between the second end of the primary winding of a respective first coupled inductor and the first node, wherein each auxiliary circuit comprises a respective second coupled inductor of the set of second coupled inductors, a respective first capacitor of the set of first capacitors, and the secondary winding of a respective first coupled inductor electrically coupled in series. ### Claim 10 (depends on 9) The ripple reduction circuit of claim 9, further comprising a set of second capacitors at an output of the ripple reduction circuit, each second capacitor having a second upstream end and a second downstream end, wherein the set of second capacitors are coupled together at the second downstream end to define a second node, wherein each second capacitor of the set of second capacitors is coupled between the second end of the primary winding of a respective first coupled inductor and the second node. ### Claim 11 (depends on 10) The ripple reduction circuit of claim 10, wherein each capacitor of the set of second capacitors is coupled to receive a respective phase voltage. ### Claim 12 (depends on 10) The ripple reduction circuit of claim 10, wherein each capacitor of the set of second capacitors is coupled electrically in parallel with a respective auxiliary circuit of the set of auxiliary circuits. ### Claim 13 (depends on 9) The ripple reduction circuit of claim 9, wherein each auxiliary circuit of the set of auxiliary circuits corresponds to a respective phase voltage. ### Claim 14 (depends on 9) The ripple reduction circuit of claim 9, further comprising a set of third coupled inductors, being magnetically coupled on a third common core, each third coupled inductor of the set of third coupled inductors being electrically coupled in series with the primary winding of a respective first coupled inductor of the set of first coupled inductors at an input of the ripple reduction circuit. ### Claim 15 (depends on 9) The ripple reduction circuit of claim 9, wherein the polyphase AC voltage source comprises a low frequency modulated high frequency AC voltage source. ### Claim 16 (depends on 9) The ripple reduction circuit of claim 9 wherein the polyphase AC source is a 3-phase AC source. ### Claim 17 A method of reducing a ripple current in a polyphase AC circuit, comprising: providing a set of first coupled inductors wound on a first common core, each first coupled inductor having a respective primary winding having a first end and a second end, and a secondary winding; arranging the first end of each primary winding of the set of first coupled inductors to receive a respective AC phase voltage; providing a set of first capacitors, each first capacitor each defining a respective first upstream end and a first downstream end; providing a set of second coupled inductors wound on a common core; coupling the first downstream end of each first capacitor of the set of first capacitors together to define a first node; and arranging a set of auxiliary circuits, each auxiliary circuit corresponding to a respective phase voltage and coupled between the second end of the primary winding of a respective first coupled inductor and the first node, wherein each auxiliary circuit comprises a respective second coupled inductor of the set of second coupled inductors, a respective first capacitor of the set of first capacitors, and the secondary winding of a respective first coupled inductor electrically coupled in series. ### Claim 18 (depends on 17) The method of claim 17, further comprising: providing a set of second capacitors, each second capacitor defining a respective second upstream end and a second downstream end; coupling the second downstream end of each second capacitor of the set of second capacitors together to define a second node; and coupling each second capacitor of the set of second capacitors between the second end of the primary winding of a respective first coupled inductor and the second node. ### Claim 19 (depends on 18) The method of claim 18, wherein the first and second nodes comprise a neutral line of the AC source. ### Claim 20 (depends on 17) The method of claim 17, further comprising: providing a set of third coupled inductors wound on a common core; and coupling a respective third coupled inductor in series with the primary winding of a respective coupled first inductor of the set of first coupled inductors.