Electric motor structure to minimize electro-magnetic interference

Patent metadata

Field	Value
Publication number	US-9343939-B2
Application number	US-97780010-A
Country	US
Kind code	B2
Filing date	Dec 23, 2010
Priority date	Dec 23, 2010
Publication date	May 17, 2016
Grant date	May 17, 2016

Abstract

An electric motor is configured with a stator core assembly that includes a stator core having a plurality of winding slots. A plurality of stator windings pass through the plurality of winding slots that include slot liners configured to provide electrostatic shields surrounding the plurality of stator windings. The electrostatic shields are referenced to an electrical location to reduce common mode currents associated with the electric motor.

First claim

We claim:

1. An electric motor comprising:
one or more motor winding power lead wires;
a stator core comprising a plurality of winding slots;
a plurality of slot liners, each slot liner disposed at least partially within a corresponding winding slot, wherein each slot liner comprises an electrically conductive layer devoid of any insulation on the inner surface and only one layer of insulation, the electrically conductive layer electrically insulated from the stator core by the only one layer of insulation, and further wherein the plurality of conductive layers are electrically connected together in parallel via an interconnecting wire or conductive ring, to provide a common connection point, wherein one end of each of the plurality of conductive layers overlaps the other end and further wherein the interconnecting wire or conductive ring is connected directly to a return node of an electrical inverter that is different from ground via a common mode current return path; and
a common mode inductor around both the one or more motor winding power lead wires and the common mode current return path connected to the interconnecting wire or conductive ring.

2. The electric motor according to claim 1 , wherein the electrically conductive layer comprises a thickness between about 0.0001 inch and about 0.005 inch.

3. The electric motor according to claim 1 , wherein the only one layer of insulation comprises a thickness between about 0.001 inch and about 0.05 inch.

4. The electric motor according to claim 1 , further comprising a plurality of stator windings passing through the plurality of winding slots, wherein the plurality of slot liner conductive layers are electrically connected together in parallel to provide electrostatic shields surrounding the plurality of stator windings.

5. The electric motor according to claim 4 , further comprising a plurality of stator winding end caps configured to reduce predetermined capacitive current flow associated with the plurality of stator windings.

6. The electric motor according to claim 5 , wherein each end cap is electrically insulated from any metallic portions of a corresponding electric motor.

7. The electric motor according to claim 5 , wherein each end cap comprises an opening to accommodate a rotor shaft to pass there through.

8. The electric motor according to claim 4 , further comprising a plurality of stator winding end caps configured to capture capacitive current flow associated with end portions of the stator windings.

9. The electric motor according to claim 1 , wherein the electrically conductive layer comprises an electrically conductive foil.

10. The electric motor according to claim 1 , further comprising a resonance reduction resistor in series with the interconnecting wire or conductive ring, wherein the resonance reduction resistor reduces resonance between a corresponding slot liner capacitance and a corresponding slot liner wire assembly inductance.

11. An electric motor comprising:
one or more motor winding power lead wires;
a stator core comprising a plurality of winding slots;
a plurality of stator windings passing through the plurality of winding slots;
a plurality of slot liners, each slot liner comprising an electrically conductive layer disposed between a corresponding stator winding and the stator core, each conductive layer devoid of any insulation on the inner surface and comprising only one layer of insulation, the electrically conductive layer electrically insulated from its corresponding stator winding and the stator core by the only one layer of insulation, wherein the plurality of conductive layers are electrically connected together in parallel via an interconnecting wire or conductive ring, to provide a common connection point, wherein one end of each of the plurality of conductive layers overlaps the other end and further wherein the interconnecting wire or conductive ring is connected directly to a return node of an electrical inverter that is different from ground via a common mode current return path; and
a common mode inductor around both the one or more motor winding power lead wires and the common mode current return path connected to the interconnecting wire or conductive ring.

12. The electric motor according to claim 11 , wherein the conductive layer comprises a thickness between about 0.0001 inch and about 0.005 inch.

13. The electric motor according to claim 11 , further comprising a plurality of stator winding end caps configured to reduce predetermined capacitive current flow associated with the plurality of stator windings.

14. The electric motor according to claim 13 , wherein each end cap is electrically insulated from any metallic portions of a corresponding electric motor.

15. The electric motor according to claim 13 , wherein each end cap comprises an opening to accommodate a rotor shaft to pass there through.

16. The electric motor according to claim 11 , wherein the one layer of insulation comprises a thickness between about 0.001 inch and about 0.05 inch.

17. The electric motor according to claim 11 , wherein the electrically conductive layer comprises an electrically conductive foil.

18. The electric motor according to claim 11 , further comprising a plurality of stator winding end caps configured to capture capacitive current flow associated with end portions of the stator windings.

19. The electric motor according to claim 11 , further comprising a resonance reduction resistor in series with the interconnecting wire or conductive ring, wherein the resonance reduction resistor reduces resonance between a corresponding slot liner capacitance and a corresponding slot liner wire assembly inductance.

20. An electric motor comprising:
one or more motor winding power lead wires;
a stator core comprising a plurality of winding slots;
a plurality of stator windings passing through the plurality of winding slots; and
a plurality of stator slot liners, each slot liner configured to provide an electrostatic shield at least partially surrounding a corresponding stator slot winding, wherein each of the plurality of electrostatic shields is devoid of any insulation on the inner surface and comprises only one layer of insulation and is electrically insulated from the stator core by the only one layer of insulation and further wherein the plurality of electrostatic shields are connected together in parallel via an interconnecting wire or conductive ring, to provide a common connection point, and further wherein the interconnecting wire or conductive ring is connected directly to a return node of an electrical inverter that is different from ground via a common mode current return path wherein one end of each of the plurality of electrostatic shields overlaps the other end; and
a common mode inductor around both the one or more motor winding power lead wires and the common mode current return path connected to the interconnecting wire or conductive ring.

21. The electric motor according to claim 20 , further comprising a plurality of stator winding end caps configured to reduce predetermined capacitive current flow associated with the plurality of stator windings.

22. The electric motor according to claim 21 , wherein each end cap is electrically insulated from any metallic portions of a corresponding electric motor.

23. The electric motor according to claim 20 , wherein the electrically conductive layer comprises an electrically conductive foil.

24. T

Assignees

• Schutten Michael Joseph
• Shah Manoj Ramprasad
• Prabhakaran Satish
• Thomas Robert James
• Gen Electric

Inventors

• Schutten Michael Joseph
• Shah Manoj Ramprasad
• Prabhakaran Satish
• Thomas Robert James

Classifications

• H02M2001/123

  Electricity · mapped topic

• H02K11/0005

  Electricity · mapped topic

• H02K3/345 Primary

  between conductor and core, e.g. slot insulation · CPC title

• H02K3/487

  Slot-closing devices · CPC title

• H02M1/44

  Circuits or arrangements for compensating for electromagnetic interference in converters or inverters · CPC title