Method and apparatus for determining an actual junction temperature of an IGBT device

Patent metadata

Field	Value
Publication number	US-9683898-B2
Application number	US-201615078588-A
Country	US
Kind code	B2
Filing date	Mar 23, 2016
Priority date	Sep 24, 2013
Publication date	Jun 20, 2017
Grant date	Jun 20, 2017

Abstract

The present invention relates to a method for determining an actual junction temperature (T j ) and/or an actual collector current (I C ) of an IGBT device, wherein the IGBT device has a main emitter (E M ) and an auxiliary emitter (E A ), comprising the steps of;
measuring the characteristics of an emitter voltage drop (V EE′ ) as a difference between a main emitter voltage (V E ) at the main emitter (E M ) and an auxiliary emitter voltage (V E′ ) at the auxiliary emitter (E A ) during a switching operation of the IGBT device; and determining the junction temperature and/or the collector current (I C ) based on the characteristics of the emitter voltage drop (V EE′ ).

First claim

The invention claimed is:

1. A method for determining an actual junction temperature (T j ) of an IGBT device, wherein the IGBT device has a main emitter (E M ) and an auxiliary emitter (E A ), comprising the steps of:
measuring the characteristics of an emitter voltage drop (V EE′ ) as a difference between a main emitter voltage (V E ) at the main emitter (E M ) and an auxiliary emitter voltage (V E′ ) at the auxiliary emitter (E A ) during a switching operation of the IGBT device; and
determining the junction temperature based on the characteristics of the emitter voltage drop (V EE′ ),
wherein the junction temperature (T j ) is determined by the steps of:
assigning a reference peak voltage of the emitter voltage drop (V EE′ ) during the switching operation to a provided collector emitter voltage (V DC ) of the IGBT device and a determined collector current (I C ), wherein the reference peak voltage corresponds to a peak voltage of the emitter voltage drop (V EE′ ) during a switching operation at a reference temperature;
determining a peak voltage of the emitter voltage drop (V EE′ ) during the switching operation; and
determining the actual junction temperature (T j ) depending on the determined peak voltage and the reference peak voltage.

2. A method according to claim 1 , wherein the peak voltage of the emitter voltage drop (V EE′ ) is determined during the switching operation by loading a memory capacitance (MC) with a load current proportional to the emitter voltage drop (V EE′ ) and providing the memory capacitance voltage as an indication of the peak voltage.

3. A method according to claim 1 , wherein the actual junction temperature (T j ) is determined depending on a peak voltage difference between the determined peak voltage and the reference peak voltage and a sensitivity of the characteristics of the peak voltage over junction temperature of the IGBT device.

4. A method according to claim 1 , wherein assigning the reference peak voltage is performed by a provided lookup function determining a relation between peak voltages at reference temperatures and collector currents (I C ).

5. A method according to claim 4 , wherein the peak voltage of the emitter voltage drop (V EE′ ) is determined during the switching operation by loading a memory capacitance (MC) with a load current proportional to the emitter voltage drop (V EE′ ) and providing the memory capacitance voltage as an indication of the peak voltage.

6. A method according to claim 4 , wherein the actual junction temperature (T j ) is determined depending on a peak voltage difference between the determined peak voltage and the reference peak voltage and a sensitivity of the characteristics of the peak voltage over junction temperature of the IGBT device.

7. A method according to claim 1 , wherein the collector current (I C ) is determined based on an integration of the emitter voltage drop (V EE′ ) over time during the switching operation.

8. A method according to claim 7 , wherein assigning the reference peak voltage is performed by a provided lookup function determining a relation between peak voltages at reference temperatures and collector currents (I C ).

9. A method according to claim 7 , wherein the peak voltage of the emitter voltage drop (V EE′ ) is determined during the switching operation by loading a memory capacitance (MC) with a load current proportional to the emitter voltage drop (V EE′ ) and providing the memory capacitance voltage as an indication of the peak voltage.

10. A method according to claim 7 , wherein the actual junction temperature (T j ) is determined depending on a peak voltage difference between the determined peak voltage and the reference peak voltage and a sensitivity of the characteristics of the peak voltage over junction temperature of the IGBT device.

11. An apparatus for determining an actual junction temperature (T j ) of an IGBT device, wherein the IGBT device has a main emitter (E M ) and an auxiliary emitter (E A ), characterized by:
means for measuring the characteristics of an emitter voltage drop (V EE′ ) as a difference between a main emitter voltage (V E ) at the main emitter (E M ) and an auxiliary emitter voltage (V E′ ) at the auxiliary emitter (E A ) during a switching operation of the IGBT device; and
means for determining the junction temperature based on the characteristics of the emitter voltage drop (V EE′ ),
a first lookup function block for assigning a reference peak voltage of the emitter voltage drop (V EE′ ) during the switching operation to a provided collector emitter voltage (V DC ) of the IGBT device and a determined collector current (I C ), wherein the reference peak voltage corresponds to a peak voltage of the emitter voltage drop (V EE′ ) during a switching operation at a reference temperature and;
a second lookup function block for determining the actual junction temperature (T j ) depending on a determined peak voltage and the reference peak voltage.

12. An apparatus according to claims 11 , wherein a comparator is provided which is configured to provide a voltage peak difference which is supplied to the second lookup function block.

13. An apparatus according to claim 11 , wherein an integrator is provided which is configured to determine the collector current (I C ) based on an integration of the emitter voltage drop (V EE′ ) over time during the switching operation.

14. An apparatus according to claim 13 , wherein a comparator is provided which is configured to provide a voltage peak difference which is supplied to the second lookup function block.

15. An apparatus according to claim 13 , wherein the integrator comprises an active diode block and a memory capacitance block, wherein the active diode block, transmits the emitter voltage drop (V EE′ ) to the memory capacitance block through a diode with a theoretical zero-voltage drop.

16. An apparatus according to claim 11 , wherein a peak voltage detector is provided which is configured to determine the peak voltage of the emitter voltage drop (V EE′ ) during the switching operation.

17. An apparatus according to claim 16 , wherein the integrator comprises an active diode block and a memory capacitance block, wherein the active diode block transmits the emitter voltage drop (V EE′ ) to the memory capacitance block through a diode with a theoretical zero-voltage drop.

18. An apparatus according to claim 16 , wherein an integrator is provided which is configured to determine the collector current (I C ) based on an integration of the emitter voltage drop (V EE′ ) over time during the switching operation.

19. An apparatus according to claim 16 , wherein a comparator is provided which is configured to provide a voltage peak difference which is supplied to the second lockup function block.

Assignees

• Abb Technology Ag
• Abb Schweiz Ag

Inventors

• Sundaramoorthy Vinoth
• Bianda Enea
• Bloch Richard
• Nistor Iulian
• Knapp Gerold

Classifications

• G01K7/01 Primary

  using semiconducting elements having PN junctions (G01K7/02, G01K7/16, G01K7/30 take precedence) · CPC title