IGBT gate drive circuit and method

Patent metadata

Field	Value
Publication number	US-9748947-B1
Application number	US-201615207585-A
Country	US
Kind code	B1
Filing date	Jul 12, 2016
Priority date	Jul 12, 2016
Publication date	Aug 29, 2017
Grant date	Aug 29, 2017

Abstract

There are provided methods and systems for operating insulated gate bipolar transistors (IGBTs). For example, there is provided a method that can include detecting a desaturation condition in an IGBT and initiating a turn off procedure when desaturation is detected. The turn off procedure can include holding a gate of the IGBT at at least one voltage level intermediate between a positive rail voltage and a negative rail voltage of an operational range of the IGBT.

First claim

What is claimed is:

1. A method for operating an insulated gate bipolar transistor (IGBT), comprising:
detecting a desaturation condition in the IGBT; and
initiating a turn off procedure when desaturation is detected, the turn off procedure including:
holding a gate of the IGBT at at least one voltage level intermediate between a positive rail voltage and a negative rail voltage of an operational range of the IGBT; and
controlling a gate resistance of the IGBT during the turn off procedure; and
wherein when the at least one voltage level includes a first voltage and a second voltage less than the first voltage, the gate resistance at the first voltage is lower than the gate resistance at the second voltage.

2. The method of claim 1 , further comprising controlling a time at which the gate is held at the at least one voltage level during the turn off procedure.

3. The method of claim 1 , further comprising controlling a time at which the gate is held at the at least one voltage level during the turn off procedure.

4. The method of claim 2 , wherein for one of the at least one voltage level the time is longer than a switching time of the IGBT.

5. The method of claim 1 , wherein the at least one voltage level is smaller than a turn on threshold voltage of the IGBT.

6. The method of claim 1 , further comprising setting the gate voltage at the negative rail voltage after holding the gate of the IGBT at the at least one voltage level.

7. The method of claim 1 , wherein the desaturation condition is a short circuit current.

8. The method of claim 1 , wherein the desaturation condition is a collector-to-emitter voltage overshoot.

9. The method of claim 1 , wherein detecting the desaturation condition includes comparing a collector-to-emitter voltage to a desaturation threshold voltage.

10. A method for operating an insulated gate bipolar transistor (IGBT), comprising:
detecting a desaturation condition in the IGBT; and
initiating a turn off procedure when desaturation is detected, the turn off procedure including:
holding a gate of the IGBT at a first voltage for a duration of at least a first hold time;
setting a gate resistance of the IGBT to a first resistance while the gate is held at the first voltage;
detecting whether the desaturation condition has ended, and in response to the desaturation having ended:
holding the gate at a second voltage for a duration of at least a second hold time;
setting the gate resistance to a second resistance while the gate is held at the second voltage; and
holding the gate at a third voltage to reach a steady-state off condition.

11. The method of claim 10 , wherein the first voltage is lower than a turn on threshold voltage of the IGBT.

12. The method of claim 11 , wherein the first voltage is greater than the second voltage, and the second voltage is greater than the third voltage.

13. The method of claim 10 , wherein the second resistance is greater than the first resistance.

14. The method of claim 10 , wherein the second hold time is longer than a switching time of the IGBT.

15. The method of claim 10 , wherein the third voltage is a negative rail voltage of an operational range of the IGBT.

16. The method of claim 10 , wherein the first voltage and the second voltage are between a positive rail voltage and a negative rail voltage of an operational range of the IGBT.

17. A non-transitory computer-readable storage medium for use with an insulated gate bipolar transistor (IGBT), the computer-readable storage medium including instructions that when executed by a processor, cause the processor to perform operations comprising:
detecting a desaturation condition in the IGBT; and
initiating a turn off procedure when desaturation is detected, the turn off procedure including:
holding a gate of the IGBT at a first voltage for a duration of at least a first hold time;
setting a gate resistance of the IGBT to a first resistance while the gate is held at the first voltage;
detecting whether the desaturation condition has ended, and in response to the desaturation having ended:
holding the gate at a second voltage for a duration of at least a second hold time;
setting the gate resistance to a second resistance while the gate is held at the second voltage; and
holding the gate at a third voltage to reach a steady-state off condition.

18. A system for operating an insulated gate bipolar transistor (IGBT), the system comprising:
a processor; and
a memory storing instructions that, when executed by the processor, configure the processor to perform operations comprising:
detecting a desaturation condition in the IGBT; and
initiating a turn off procedure when desaturation is detected, the turn off procedure including:
holding a gate of the IGBT at a first voltage for a duration of at least a first hold time;
setting a gate resistance of the IGBT to a first resistance while the gate is held at the first voltage;
detecting whether the desaturation condition has ended, and in response to the desaturation having ended:
holding the gate at a second voltage for a duration of at least a second hold time;
setting the gate resistance to a second resistance while the gate is held at the second voltage; and
holding the gate at a third voltage to reach a steady-state off condition.

Assignees

• Ge Energy Power Conversion Technology Ltd
• Ge Energy Power Conversion Technology Ltd

Inventors

• Wagoner Robert Gregory
• Schuetz Tobias
• Greenleaf Todd David
• Tackman Terry Michael

Classifications

• H03K17/567 Primary

  Circuits characterised by the use of more than one type of semiconductor device, e.g. BIMOS, composite devices such as IGBT · CPC title

• H03K17/0828 Primary

  in composite switches · CPC title

• H03K17/168

  in composite switches · CPC title