Snubber circuit located between an output line and low impedance potential

• US 5,258,902 A
• Filed: 05/11/1992
• Issued: 11/02/1993
• Est. Priority Date: 05/11/1992
• Status: Expired due to Term

• Current Assignee: Simmonds Precision Engine Systems Incorporated (Rtx Corporation)
• Original Assignee: Simmonds Precision Products, Inc. (Rtx Corporation)
• Inventors: Lindbery, John R., Flanagan, David F.
• Primary Examiner(s): STERRETT, JEFFREY L
• Application Number:
  US07/882,191
• Time in Patent Office: 540 Days
• Field of Search: 363/17, 363/55, 363/56, 363/58, 363/95, 363/96, 363/98, 363/132
• US Class Current: 363/56.12
• CPC Class Codes: H02M 1/34 Snubber circuits
• CPC Class Codes: H02M 1/348 Passive dissipative snubbers
• CPC Class Codes: H02M 7/538 in a push-pull configuration H02M7/5375 takes precedence ; with oscillating arrangements H02M7/53832, H02M7/53846
• CPC Class Codes: H03K 17/08142 in field-effect transistor switches
• CPC Class Codes: H03K 17/08148 in composite switches

Abstract

A dual snubber circuit for a switching circuit including first snubber means for performing a first snubbering function in a switching operation of the switching circuit, and second snubber means for performing a second snubbering function in the switching operation of the switching circuit, the first and second snubber means performing the first and second snubbering functions substantially independently.

Claims

1. A dual snubber circuit for a switching circuit in an inverter circuit for inverting DC power provided on a first supply potential and a second supply potential into AC power on an output line, said switching circuit being coupled between at least one of said supply potentials and said output line, said dual snubber circuit comprising:

first snubber means coupled across said switching circuit for performing a first snubbering function in a switching operation of said switching circuit; and

second snubber means coupled between said output line and a low impedance potential other than said first and second supply potentials, for performing a second snubbering function in the switching operation of said switching circuit, said second snubbering function comprising suppressing and controlling oscillations resulting from said switching operation.

2. The dual snubber circuit of claim 1, wherein said first snubbering function comprises limiting the peak voltage developed across a switch of said switching circuit in performing said switching operation.

3. The dual snubber circuit of claim 1, said inverter circuit being a three-phase, full-bridge inverter.

4. The dual snubber circuit of claim 1, said inverter circuit being a pulse width modulated inverter circuit.

5. The dual snubber circuit of claim 1, wherein said first snubbering function comprises limiting the peak voltage developed across said switching circuit.

6. The dual snubber circuit of claim 5, wherein each of said first and second snubber means comprises at least one of a resistor-capacitor circuit and a resistor-capacitor-diode circuit.

7. The dual snubber circuit of claim 5, wherein said second snubber means comprises a resistor and a capacitor connected in series.

8. The dual snubber circuit of claim 1, said inverter circuit having a resonant pole topology as a function of said second snubber means and an output inductor included at an output of said inverter circuit.

9. A dual snubber circuit for a switching circuit in an inverter circuit for inverting DC power provided on a first supply potential and a second supply potential into AC power on an output line, said switching circuit being coupled between at least one of said supply potentials and said output line, said dual snubber circuit comprising:

first snubber means coupled across said switching circuit for performing a first snubbering function in a switching operation of said switching circuit;

second snubber means coupled between said output line and a low impedance potential other than said first and second supply potentials, for performing a second snubbering function in the switching operation of said switching circuit; and

said first snubber means further comprising means for performing a third snubbering function, said third snubbering function comprising limiting the current in said switching circuit.

10. The dual snubber circuit of claim 9, said means for performing said third snubbering function comprising an inductor connected in series with a switch of said switching circuit.

11. A snubber circuit for a switching circuit in an inverter circuit for inverting DC power provided on a first supply potential and a second supply potential into AC power on an output line, said switching circuit being coupled between at least one of said supply potentials and an output line, said snubber circuit comprising:

a circuit comprising at least one snubber element coupled between said output line and a low impedance potential other than said first and second supply potentials, for performing a snubbering function in a switching operation of said switching circuit, said snubbering function comprising suppressing and controlling oscillations resulting from said switching operation.

12. The snubber circuit of claim 11, wherein said snubber circuit forms a resonant pole including said inverter circuit to effect soft switching during a switching operation of said switching circuit.

13. The snubber circuit of claim 11, further comprising an output inductor in said output line, said output inductor and said snubber element combining to form a resonant pole topology.

14. The snubber circuit of claim 11, wherein the voltage on said low impedance potential is at a level between said first and second supply potentials.

15. A dual snubber circuit for a switching circuit in an inverter circuit for inverting DC power provided on a first supply potential and a second supply potential into AC power on an output line, said dual snubber circuit comprising:

first snubber means for performing a first snubbering function, said first snubber means being coupled across a switch of said switching circuit which is coupled between said output line and at least one of said first and second supply potentials;

second snubber means for performing a second snubbering function, said second snubber means being coupled between said output line and a low impedance potential other than said first and second supply potentials;

wherein said second snubber means forms a resonant pole including said inverter circuit to effect soft switching during a switching operation of said switch; and

said first snubber means further comprising means for limiting the current in said dual snubber circuit.

16. A dual snubber circuit for a switching circuit in an inverter circuit for inverting DC power provided on a first supply potential and a second supply potential into AC power on an output line, said dual snubber circuit comprising:

first snubber means for performing a first snubbering function, said first snubber means being coupled across a switch of said switching circuit which is coupled between said output line and at least one of said first and second supply potentials;

second snubber means for performing a second snubbering function comprising suppressing and controlling oscillations resulting from a switching operation of said switch, said second snubber means being coupled between said output line and a low impedance potential other than said first and second supply potentials; and

wherein said second snubber means forms a resonant pole including said inverter circuit to effect soft switching during a switching operation of said switch.

17. The dual snubber circuit of claim 16, wherein said first snubbering function comprises limiting the peal voltage developed across said switch.

18. The dual snubber circuit of claim 17, wherein said limiting of the peak voltage occurs upon the interruption of current flow through said switch.

19. The dual snubber circuit of claim 16, wherein the voltage on said low impedance potential is at a level between said first and second supply potentials.

20. The dual snubber circuit of claim 19, wherein said first and second snubber means perform said first and second snubbering functions substantially independently.

21. The dual snubber circuit of claim 16, wherein said inverter circuit has at least two inverter switches connected in parallel, wherein each of said at least two inverter switches includes said first and second snubbering means with substantially similar circuit topologies.

22. The dual snubber circuit of claim 16, wherein each of said first and second snubber means comprises at least one of a resistor-capacitor circuit and a resistor-capacitor-diode circuit.

23. The dual snubber circuit of claim 22, wherein said second snubber means comprises a resistor and a capacitor connected in series.

24. The dual snubber circuit of claim 16, wherein the voltage on said low impedance potential is between said first and second supply potentials.

25. The dual snubber circuit of claim 24, further comprising an output inductor in said output line, said output inductor and said second snubber means combining to form a resonant pole topology.

26. A dual snubber circuit for a switching circuit in an inverter circuit for inverting DC power provided on a first supply potential and a second supply potential into AC power on an output line, said dual snubber circuit comprising:

first snubber means for performing a first snubbering function, said first snubber means being coupled across a switch of said switching circuit which is coupled between said output line and at least one of said first and second supply potentials;

second snubber means for performing a second snubbering function, said second snubber means being coupled between said output line and a low impedance potential other than said first and second supply potentials;

said inverter circuit having at least two inverter switches connected in parallel, each of said at least two inverter switches including said first and second snubbering means with substantially similar circuit topologies;

wherein said second snubber means forms a resonant pole including said inverter circuit to effect soft switching during a switching operation of said switch; and

further comprising means for balancing the switch currents through said at least two inverter switches.