Control device for an inverter, electric drive system and method for establishing a safe operating mode

Patent metadata

Field	Value
Publication number	US-12445068-B2
Application number	US-202117927396-A
Country	US
Kind code	B2
Filing date	Apr 30, 2021
Priority date	May 25, 2020
Publication date	Oct 14, 2025
Grant date	Oct 14, 2025

Abstract

The present invention relates to establishing a rotational speed-dependent safe operating mode. For this purpose, two redundant control paths are provided and are each designed to establish either an active short-circuit or a freewheeling mode as the safe operating mode. In this way, even if one control path fails, a rotational speed-dependent safe operating mode can still be fully established.

First claim

The invention claimed is:

1. A control device for an inverter ( 30 ) in an electric drive system, the control device comprising:
a first processor ( 25 ) and a second processor ( 25 ) which are each configured to establish a safe operating mode in a shared inverter ( 30 ) connected to both the first processor ( 25 ) and the second processor ( 25 ),
wherein the first processor ( 25 ) is configured to determine a rotational speed of an electric machine ( 3 ) of the electric drive system and, using the determined rotational speed of the electric machine ( 3 ), to establish, as the safe operating mode, either an active short-circuit or a freewheeling mode in the shared inverter ( 30 );
wherein the second processor ( 25 ) is configured to determine the rotational speed of the electric machine ( 3 ) of the electric drive system and, using the determined rotational speed of the electric machine ( 3 ), to establish, as the safe operating mode, either the active short-circuit or the freewheeling mode in the shared inverter ( 30 ), and
wherein the first processor ( 25 ) and/or the second processor ( 25 ) are configured to establish an active short-circuit in the inverter ( 30 ) in response to the determined rotational speed of the electric machine ( 3 ) exceeding a first threshold value (n 1 ), and to establish a freewheeling mode in response to the determined rotational speed of the electric machine ( 3 ) falling below a second threshold value (n 2 ).

2. The control device according to claim 1 , wherein the control device is configured to control a plurality of half-bridges of the shared inverter, and
wherein the first processor ( 25 ) and/or the second processor ( 25 ) are configured to control switching elements (L 1 , L 2 , L 3 , H 1 , H 2 , H 3 ) in the half-bridges, using phase currents in corresponding phases, for the establishment of a freewheeling mode.

3. The control device according to claim 1 , wherein the control device is configured to control an inverter ( 30 ) having a plurality of half-bridges, and
wherein the first processor ( 25 ) and/or the second processor ( 25 ) are configured to control switching elements (L 1 , L 2 , L 3 , H 1 , H 2 , H 3 ) in the half-bridges, using phase voltages in corresponding phases, for the establishment of an active short-circuit.

4. The control device according to claim 1 , wherein the first processor ( 25 ) is configured to verify the determined rotational speed of the electric machine ( 3 ) using the rotational speed determined by the second processor ( 25 ).

5. The control device according to claim 1 , wherein the first processor ( 25 ) is configured to be fed from a low-voltage side of the electric drive system, and the second processor ( 25 ) is configured to be fed from a high-voltage side of the electric drive system.

6. The control device according to claim 1 , wherein the second processor ( 25 ) is configured to establish the freewheeling mode as a safe operating mode in the event that an intermediate circuit voltage of the shared inverter ( 30 ) falls below a predetermined first threshold voltage.

7. The control device according to claim 6 , wherein the second processor ( 25 ) is configured to establish the active short-circuit as a safe operating mode in the event that an intermediate circuit voltage of the shared inverter exceeds a predetermined second threshold voltage and the determined rotational speed is greater than the first threshold voltage.

8. The control device according to claim 1 , wherein the second processor ( 25 ), which is configured to determine the rotational speed of the electric machine ( 3 ) during the active short-circuit using forward voltages through switching elements in the shared inverter ( 30 ).

9. The control device according to claim 1 , wherein the second processor ( 25 is configured to determine the rotational speed of the electric machine ( 3 ) during the freewheeling mode under at least two phase voltages of the electric machine ( 3 ).

10. An electric drive system comprising:
an electric machine ( 3 );
an shared inverter ( 30 ) which is configured to control the electric machine ( 3 ); and
a control device including
a first processor ( 25 ) and a second processor ( 25 ) which are each connected to the shared inverter and configured to establish a safe operating mode in the shared inverter ( 30 ) of the electric drive system,
wherein the first processor ( 25 ) is configured to determine a rotational speed of an electric machine ( 3 ) of the electric drive system and, using the determined rotational speed of the electric machine ( 3 ), to establish, as the safe operating mode, either an active short-circuit or a freewheeling mode in the shared inverter ( 30 );
wherein the second processor ( 25 ) is configured to determine the rotational speed of the electric machine ( 3 ) of the electric drive system and, using the determined rotational speed of the electric machine ( 3 ), to establish, as the safe operating mode, either the active short-circuit or the freewheeling mode in the shared inverter ( 30 ), and
wherein the first processor ( 25 ) and/or the second processor ( 25 ) are configured to establish an active short-circuit in the inverter ( 30 ) in response to the determined rotational speed of the electric machine ( 3 ) exceeding a first threshold value (n 1 ), and to establish a freewheeling mode in response to the determined rotational speed of the electric machine ( 3 ) falling below a second threshold value (n 2 ).

11. A method for establishing a safe operating mode in an electric drive system, the method comprising the steps of:
determining (S 11 ) a rotational speed of an electric machine ( 3 ) of the electric drive system and establishing (S 12 ) a safe operating mode in the electric machine ( 3 ) by means of redundant processors ( 25 ), each configured to establish (S 21 ) a safe operating mode using the determined rotational speed by establishing either an active short-circuit or a freewheeling mode in a shared inverter ( 30 ) of the electric drive system, and
wherein the redundant processors ( 25 ) are each configured to establish an active short-circuit in the inverter ( 30 ) in response to the determined rotational speed of the electric machine ( 3 ) exceeding a first threshold value (n 1 ), and to establish a freewheeling mode in response to the determined rotational speed of the electric machine ( 3 ) falling below a second threshold value (n 2 ).

12. The method as claimed in claim 11 , wherein at least one of the redundant processors ( 25 ) is fed power by a high-voltage side of the electric drive system.

13. A method for establishing a safe operating mode in an electric drive system, the method comprising the steps of:
determining (S 11 ) a rotational speed of an electric machine ( 3 ) of the electric drive system and establishing (S 12 ) a safe operating mode in the electric machine ( 3 ) by means of a first processor ( 25 ) wherein the establishment (S 12 ) of the safe operating mode, via the first processor ( 25 ) using the determined rotational speed, establishes either an active short-circuit or a freewheeling mode in a shared inverter ( 30 ) of the electric drive system;
determining (S 21 ) a rotational speed of the electric machine ( 3 ) of the electric drive system and establishing (S 22 ) the safe operating mode in the electric machine ( 3 ) by means of a second processor ( 25 ), wherein the establishment (S 22 ) of the safe operating mode, via the second processor ( 25 ) using the determined rotational speed establishes, either the active short-circuit or the freewheeling mode in the shared inverter ( 30 ) of the electric drive system,
wher

Assignees

• Bosch Gmbh Robert

Inventors

• Eberlein Edwin
• Raichle Daniel
• Kirschner Manfred
• Merkel Thomas
• Knorpp Thomas
• Gilgenbach Volker

Classifications

• H02P6/16

  Circuit arrangements for detecting position · CPC title

• H02H7/08

  for dynamo-electric motors · CPC title

• Y02T10/64

  Electric machine technologies in electromobility · CPC title

• H02P3/22 Primary

  by short-circuit or resistive braking · CPC title

• H02P3/18 Primary

  for stopping or slowing an AC motor · CPC title