US 12,451,832 B2
Method for operating an inverter device of an electric drive device, control unit, electric drive device and motor vehicle
Tobias Grassl, Denkendorf (DE); Marko Kertes, Munich (DE); and Mathias Korn, Regensburg (DE)
Assigned to AUDI AG, Ingolstadt (DE); and VOLKSWAGEN AKTIENGESELLSCHAFT, Wolfsburg (DE)
Filed by AUDI AG, Ingolstadt (DE); and VOLKSWAGEN AG, Wolfsburg (DE)
Filed on Feb. 10, 2023, as Appl. No. 18/167,388.
Claims priority of application No. 10 2022 103 848.3 (DE), filed on Feb. 18, 2022.
Prior Publication US 2023/0268867 A1, Aug. 24, 2023
Int. Cl. H02P 29/032 (2016.01); B60L 50/60 (2019.01); H02P 27/06 (2006.01)
CPC H02P 29/032 (2016.02) [H02P 27/06 (2013.01); B60L 50/60 (2019.02)] 14 Claims
OG exemplary drawing
 
1. A method of operating an inverter device of an electric drive device, wherein the inverter device includes at least two half bridges with each half bridge of the at least two half bridges including a low-side switch and a high-side switch, respectively, to provide a plurality of low-side switches and a plurality of high-side switches, and is configured to be connected to a respective phase winding of a plurality of phase windings of an electric motor of the electric drive device to convert a direct voltage of an intermediate circuit, which is configured to connect a battery to the inverter device, into a multi-phase alternating current of the plurality of phase windings of the electric motor to operate the electric motor, the method comprising:
by a control unit of the electric drive device,
receiving a safety signal, which instructs the control unit to operate the electric motor in a safe operating mode including an active short circuit mode, or a freewheel mode, and to discharge the intermediate circuit via the inverter device in an active discharge mode at same time,
if the active short circuit mode is set for the safe operating mode, controlling the inverter device to operate the electric motor in the active short circuit mode and to discharge via the inverter device the intermediate circuit in the active discharge mode,
if the freewheel mode is set for the safe operating mode,
controlling the inverter device to operate the electric motor in the freewheel mode,
examining a current strength captured by a sensor unit in the electric motor to determine a satisfaction of a current criterion below a threshold indicative of admissible discharge of the intermediate circuit that reduces erratic torque change by the electric motor, and
upon satisfaction of the current criterion, controlling the inverter device to terminate operation of the electric motor in the freewheel mode and to switch to the active discharge mode to discharge via the inverter device the intermediate circuit in the active discharge mode.