CAPACITOR-SWITCHED LOSSLESS SNUBBER

• US 20080094866A1
• Filed: 07/06/2007
• Published: 04/24/2008
• Est. Priority Date: 07/06/2006
• Status: Abandoned Application

• Current Assignee: Jennifer Bauman, Mehrdad Kazerani
• Original Assignee: Jennifer Bauman, Mehrdad Kazerani
• Inventors: Bauman, Jennifer, Kazerani, Mehrdad
• Application Number:
  US11/774,208
• Publication Number:
  US 20080094866A1
• Time in Patent Office: Days
• US Class Current: 363/50
• CPC Class Codes: H02M 1/34 Snubber circuits
• CPC Class Codes: H02M 1/342 Active non-dissipative snubbers
• CPC Class Codes: Y02B 70/10 Technologies improving the efficiency by using switched-mode power supplies [SMPS], i.e. efficient power electronics conversion e.g. power factor correction or reduction of losses in power supplies or efficient standby modes

Abstract

A regenerative snubber circuit for a boost converter is provided which greatly reduces the switching losses of the IGBT in the converter. The circuit uses no additional magnetic components, has a simple control strategy, is relatively low-cost, and provides an increase in efficiency and decrease in size and mass of the converter.

Claims

1. In a power converter having a power switch, a snubber circuit comprising:

a snubber capacitor;

first and second snubber diodes;

a first auxiliary switch that, upon a first turn off of the power switch, conducts current through the first snubber diode and the snubber capacitor to charge the snubber capacitor; and

a second auxiliary switch that upon a subsequent turn off of the power switch, conducts current through the second snubber diode and the snubber capacitor to discharge the snubber capacitor.

2. The snubber circuit of claim 1, wherein the power converter is a boost converter.

3. The snubber circuit of claim 2, wherein the boost converter includes a silicon-carbide boost diode.

4. The snubber circuit of claim 1, wherein the first and second auxiliary switch are IGBTs.

5. A method for minimizing switch off losses in a power converter having an input current, a power switch set in an on position and a snubber circuit, the snubber circuit having a first auxiliary switch, a second auxiliary switch, a snubber capacitor, and first and second snubber diodes, the method comprising the steps of:

i) setting the first auxiliary switch to an on position and the second auxiliary switch to an off position;

ii) charging the snubber capacitor from zero V to V_out by setting the power switch to an off position to divert the current through the first snubber diode, the snubber capacitor and the first auxiliary switch;

iii) setting the first auxiliary switch to an off position;

iv) setting the power switch to the on position;

v) setting the second auxiliary switch to an on position;

vi) discharging the snubber capacitor from V_out to zero V by setting the power switch to the off position to divert the current through the second snubber diode, the snubber capacitor and the second auxiliary switch; and

vii) repeating steps i) through vii).

6. The method of claim 5, wherein the power converter is a boost converter.

7. The method of claim 6, wherein the boost converter includes a silicon-carbide boost diode.

8. The method of claim 5, wherein the first and second auxiliary switches are IGBTs.

9. The method of claim 5, wherein the first and second auxiliary switches are switched under zero voltage conditions.

10. A power converter having a snubber circuit, the snubber circuit comprising:

a snubber capacitor;

first and second snubber diodes;

a first auxiliary switch that, upon a first turn off of the power switch, conducts current through the first snubber diode and the snubber capacitor to charge the snubber capacitor; and

a second auxiliary switch that upon a subsequent turn off of the power switch, conducts current through the second snubber diode and the snubber capacitor to discharge the snubber capacitor.

11. The power converter of claim 10, wherein the power converter is a boost converter.

12. The power converter of claim 11, wherein the boost converter includes a silicon-carbide boost diode.

13. The power converter of claim 10, wherein the first and second auxiliary switches are IGBTs.