# US 2012/0075051 A1 · Magnetic Devices and Transformer Circuits Made Therewith > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 2012/0075051 A1 - Document ID: US20120075051A1 - Status: Published application - Kind: A1 - Application number: 13/154,942 - Filed: 2011-06-07 - Published: 2012-03-29 - Earliest claimed: 2010-09-23 - Assignees: Northern Power Systems, Inc. - Inventors: Jeffrey K. Petter; Magdalena E. Dale - Web page: https://patentgrep.com/patent/US20120075051A1 ## CPC - H01F 37/00: Fixed inductances not covered by group H01F17/00 - H01F 27/385: {for reducing harmonics} - H02M 1/0064: {Magnetic structures combining different functions, e.g. storage, filtering or transformation} - H02M 3/1584: {with a plurality of power processing stages connected in parallel} - H01F: MAGNETS; INDUCTANCES; TRANSFORMERS; SELECTION OF MATERIALS FOR THEIR MAGNETIC PROPERTIES - 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 magnetic device producing a small amount of leakage flux and capable of substantially eliminating the amount of leakage flux that escapes the magnetic core of the device. The device includes at least a portion of an electronic circuit that includes an interphase transformer arranged on a magnetic core. The reactor windings on each leg of the magnetic core are disposed in close proximity to each other and can be wound concentrically or in a bifilar fashion. The resulting combination of the magnetic core and windings provides a high degree of magnetic coupling between reactor windings disposed on the same leg and between reactor windings disposed on differing legs. The high degree of magnetic coupling substantially reduces the amount of leakage flux that can affect other metal objects proximate the magnetic device. ## Claims ### Claim 1 A magnetic device for a multiphase power converter that includes a number N of switching cells having corresponding respective N switched outputs, the magnetic device comprising: a core including N legs; pairs of reactor windings each including a primary reactor winding and a secondary reactor winding, said pairs of reactor windings disposed on corresponding respective ones of said N legs, wherein said primary reactor winding and said secondary reactor winding of each respective pair of reactor windings are separated by a distance that substantially eliminates leakage inductance, and wherein each of said pairs of reactor windings have an output in electrical communication with a common output node; and N double-winding segments each including a primary reactor winding from one of said pairs of reactor windings in series with a secondary reactor winding from another one of said pairs of reactor windings, each of said N double-winding segments having a first end electronically connected to a corresponding respective one of said N switched outputs and a second end electronically connected to said common output node. ### Claim 2 (depends on 1) A magnetic device according to claim 1, wherein said primary reactor winding and said secondary reactor winding having a turn ratio of 1:1. ### Claim 3 (depends on 1) A magnetic device according to claim 1, wherein said distance is less than the diameter of one of said pairs of reactor windings. ### Claim 4 (depends on 3) A magnetic device according to claim 3, wherein said distance is less than about 5% of the diameter of one of said pairs of reactor windings. ### Claim 5 (depends on 1) A magnetic device according to claim 1, wherein said distance is less than about 0.12 inches. ### Claim 6 (depends on 1) A magnetic device according to claim 1, wherein said distance is less than about 0.06 inches. ### Claim 7 (depends on 1) A magnetic device according to claim 1, wherein an area between said primary reactor winding and said secondary reactor winding of each respective pair of reactor windings is minimized. ### Claim 8 (depends on 5) A magnetic device according to claim 5, wherein said area is less than an area of one of said pairs of reactor windings. ### Claim 9 (depends on 6) A magnetic device according to claim 6, wherein said area is less than about 1/10 the area of one of said pairs of reactor windings. ### Claim 10 (depends on 1) A magnetic device according to claim 1, wherein said pairs of reactor windings are arranged concentrically on corresponding respective ones of said N legs. ### Claim 11 (depends on 1) A magnetic device according to claim 1, wherein said pairs of reactor windings are arranged bifilarly on corresponding respective ones of said N legs. ### Claim 12 A magnetic device having magnetizing inductance and leakage inductance, the magnetic device comprising: a core including a plurality of legs; and pairs of reactor windings disposed on corresponding respective ones of said plurality of legs, each of said pairs of reactor windings including a primary reactor winding and a secondary reactor winding, wherein said pairs of reactor windings are configured so that respective ones of said pairs of reactor windings magnetically couple to each other to generate the magnetizing inductance, and the leakage inductance is about 100 times less than the magnetizing inductance. ### Claim 13 (depends on 12) A magnetic device according to claim 12, wherein said primary reactor winding and said secondary reactor winding having a turn ratio of 1:1. ### Claim 14 (depends on 12) A magnetic device according to claim 12, wherein the leakage inductance is about 1000 times less than the magnetizing inductance. ### Claim 15 (depends on 12) A magnetic device according to claim 12, wherein individual ones of each of said pairs of reactor windings are separated by distance, wherein said distance is less than about 5% of the diameter of one of said pairs of reactor windings. ### Claim 16 (depends on 15) A magnetic device according to claim 15, wherein said distance is less than about 0.12 inches. ### Claim 17 (depends on 12) A magnetic device according to claim 12, wherein an area between said pairs of reactor windings is minimized. ### Claim 18 (depends on 17) A magnetic device according to claim 17, wherein said area between said pairs of reactor windings is less than an area of one of said pairs of reactor windings. ### Claim 19 (depends on 18) A magnetic device according to claim 18, wherein said area between said primary reactor winding and said secondary reactor winding is less than about 1/10 the area of one of said pairs of reactor windings. ### Claim 20 (depends on 12) A magnetic device according to claim 12, wherein said pairs of reactor windings are arranged concentrically or bifilarly on corresponding respective ones of said plurality of legs.