Methods and systems for reducing conducted electromagnetic interference

• US 9,178,485 B2
• Filed: 03/06/2013
• Issued: 11/03/2015
• Est. Priority Date: 03/06/2013
• Status: Active Grant

• Current Assignee: Regal Beloit America, Inc. (Regal Rexnord Corp.)
• Original Assignee: Regal Beloit America, Inc. (Regal Rexnord Corp.)
• Inventors: Nardin, Steven A.
• Primary Examiner(s): Andrews, Michael
• Application Number:
  US13/787,649
• Publication Number:
  US 20140252896A1
• Time in Patent Office: 972 Days
• Field of Search: 310/71, 310/68.R, 310/68.C, 310/72
• US Class Current: 1/1
• CPC Class Codes: H02K 11/02 for suppression of electromagnetic interference
• CPC Class Codes: H02K 11/026 Suppressors associated with brushes, brush holders or their supports
• CPC Class Codes: H02K 11/028 Suppressors associated with the rotor
• CPC Class Codes: H02K 11/04 for rectification
• CPC Class Codes: H03H 7/0138 Electrical filters or coupling circuits
• CPC Class Codes: H03H 7/427 Common-mode filters H02J3/01 and H02M1/126 takes precedence

Abstract

An EMI filter is described. The filter includes an input, an output, first and second line-side X capacitors, and a line-side Y capacitor. The input includes first and second input terminals. The output includes first and second output terminals. A first conductive path is defined between the first input terminal and the first output terminal. A second conductive path is defined between the second input terminal and the second output terminal. The first line-side X capacitor is coupled between the first conductive path and the second conductive path, and the second line-side X capacitor is coupled between the first conductive path and the second conductive path in series with the first line-side X capacitor. The second line-side X capacitor is coupled to the first line-side X capacitor at a common point. A first end of the line-side Y capacitor is coupled to the common point.

Claims

1. An electromagnetic interference (EMI) filter comprising:

an input comprising a first input terminal and a second input terminal;

an output comprising a first output terminal and a second output terminal, wherein a first conductive path is defined between the first input terminal and the first output terminal, and a second conductive path is defined between the second input terminal and the second output terminal;

a first line-side X capacitor coupled between the first conductive path and the second conductive path;

a second line-side X capacitor coupled between the first conductive path and the second conductive path in series with the first line-side X capacitor, said second line-side X capacitor coupled to said first line-side X capacitor at a common point;

a line-side Y capacitor including a first end and a second end opposite the first end, the first end of said line-side Y capacitor coupled to the common point;

a first load-side Y capacitor including a first end and a second end opposite the first end, the first end of said first load-side Y capacitor coupled to the first conductive path between said first line-side X capacitor and said output; and

a second load-side Y capacitor including a first end and a second end opposite the first end, the first end of said second load-side Y capacitor coupled to the second conductive path between said second line-side X capacitor and said output.

2. An EMI filter in accordance with claim 1, wherein said input further comprises a ground terminal, and the second end of said line-side Y capacitor is operatively coupled to the ground terminal, wherein the second end of said first load-side Y capacitor is operatively coupled to said ground terminal and the second end of said second load-side Y capacitor is operatively coupled said ground terminal.

3. An EMI filter in accordance with claim 2, further comprising a first inductor coupled in the first conductive path between said first line-side X capacitor and said first load-side Y capacitor, and a second inductor coupled in the second conductive path between said second line-side X capacitor and said second load-side Y capacitor.

4. An EMI filter in accordance with claim 3, wherein said first inductor and said second inductor comprise a common mode choke.

5. An EMI filter in accordance with claim 4, further comprising a load-side X capacitor coupled from the first conductive path to the second conductive path between said common mode choke and said output.

6. An EMI filter in accordance with claim 1, wherein said common point is not connected to a conductive path.

7. A wiring harness for an electric motor, said wiring harness comprising:

an input configured to couple to a power source;

an output configured to couple to the electric motor;

a first conductive path between said input and said output;

a second conductive path between said input and said output;

a grounding path;

a first line-side X capacitor coupled between said first conductive path and said second conductive path;

a second line-side X capacitor coupled between said first conductive path and said second conductive path in series with said first line-side X capacitor, said second line-side X capacitor coupled to said first line-side X capacitor at a common point;

a line-side Y capacitor including a first end and a second end opposite the first end, the first end of said line-side Y capacitor coupled to the common point;

a first load-side Y capacitor coupled from said first conductive path to said grounding path between said first line-side X capacitor and said output; and

a second load-side Y capacitor coupled from said second conductive path to said grounding path between said second line-side X capacitor and said output.

8. A wiring harness in accordance with claim 7, wherein the second end of said line-side Y capacitor is coupled to said grounding path.

9. A wiring harness in accordance with claim 8, further comprising a first inductor coupled in said first conductive path between said first line-side X capacitor and said first load-side Y capacitor, and a second inductor coupled in said second conductive path between said second line-side X capacitor and said second load-side Y capacitor.

10. A wiring harness in accordance with claim 9, wherein said first inductor and said second inductor comprise a common mode choke.

11. A wiring harness in accordance with claim 10, further comprising a load-side X capacitor coupled from said first conductive path to said second conductive path between said common mode choke and said output.

12. A wiring harness in accordance with claim 7, wherein said common point is not connected to a conductive path.

13. An electric motor assembly comprising:

an electric motor including a power input configured to receive electrical power to operate said electric motor; and

an electromagnetic interference (EMI) filter comprising;

an input configured to couple to a power source;

an output coupled to said electric motor power input;

a first conductive path defined between said input and said output;

a second conductive path defined between said input and said output;

a grounding path;

a first line-side X capacitor coupled between said first conductive path and said second conductive path;

a second line-side X capacitor coupled between said first conductive path and said second conductive path in series with said first line-side X capacitor, said second line-side X capacitor coupled to said first line-side X capacitor at a common point;

a line-side Y capacitor including a first end and a second end opposite the first end, the first end of said line-side Y capacitor coupled to the common point;

a first load-side Y capacitor coupled from said first conductive path to said grounding path between said first line-side X capacitor and said output; and

a second load-side Y capacitor coupled from said second conductive path to said grounding path between said second line-side X capacitor and said output.

14. An electric motor assembly in accordance with claim 13, wherein the second end of said line-side Y capacitor is coupled to said grounding path.

15. An electric motor assembly in accordance with claim 14, wherein said EMI filter further comprises a first inductor coupled in said first conductive path between said first line-side X capacitor and said first load-side Y capacitor, and a second inductor coupled in said second conductive path between said second line-side X capacitor and said second load-side Y capacitor.

16. An electric motor assembly in accordance with claim 15, wherein said first inductor and said second inductor comprise a common mode choke.

17. An electric motor assembly in accordance with claim 16, wherein said EMI filter further comprises a load-side X capacitor coupled from said first conductive path to said second conductive path between said common mode choke and said output.

18. An electric motor assembly in accordance with claim 13, wherein said electric motor comprises a housing, and wherein said EMI filter is disposed within said housing.

19. An electric motor assembly in accordance with claim 13, wherein said electric motor is an electronically commutated motor configured for use in a heating, ventilation, and air conditioning (HVAC) system.

20. An electric motor assembly in accordance with claim 13, wherein said common point is not connected to a conductive path.