The invention relates to a method for protecting safety switches (Q7, Q8, Q9) of a control unit (11) of an electric motor, wherein the control unit (11) has a microcontroller (12) and a gate driver (13), which control a driver circuit (14) having 2n FETs (Q1, Q2, Q3, Q4, Q5, Q6), n being the number of phase windings of the electric motor, and the FETs being arranged in half bridges, and the safety switch being arranged in the middle tap of any half bridge, between the driver circuit (14) and the phase winding of the electric motor, wherein the safety switches are FETs, which are designed to break the electrical connection between the driver circuit (14) and any phase winding in the event of fault, and wherein the method, in the event of an electrical malfunction in the driver circuit (14), comprises the following steps: (a) activating one of the 2n FETs (Q1, Q2, Q3, Q4, Q5, Q6) of the driver circuit (14), (b) measuring the current flow in a supply line (19-) of the driver circuit (14) and detecting a current value, (c) deactivating the activated FET (Q1, Q2, Q3, Q4, Q5, Q6) of the driver circuit (14), (d) successively carrying out a test switching pattern in accordance with steps (a) to (c) for the remaining 2n-1 FETs (Q1, Q2, Q3, Q4, Q5, Q6), (e) evaluating the detected current values for failure to reach a specified threshold value, the highest detected current value being ignored, (f) in the event that the threshold value is not reached, breaking the electrical connection between the driver circuit (14) and at least one of the phase windings (u, v, w) by switching the safety switches (Q7, Q8, Q9). The invention further relates to a electromechanical motor vehicle steering system having a control unit, which is designed to carry out a method of this kind.


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    Title :

    VERFAHREN ZUM SCHUTZ EINES SICHERHEITSSCHALTERS EINER STEUEREINHEIT EINES ELEKTROMOTORS


    Additional title:

    METHOD FOR PROTECTING A SAFETY SWITCH OF A CONTROL UNIT OF AN ELECTRIC MOTOR
    PROCÉDÉ DE PROTECTION D'UN COMMUTATEUR DE SÉCURITÉ D'UNE UNITÉ DE COMMANDE D'UN MOTEUR ÉLÉCTRIQUE


    Contributors:

    Publication date :

    2023-02-08


    Type of media :

    Patent


    Type of material :

    Electronic Resource


    Language :

    German


    Classification :

    IPC:    H02P CONTROL OR REGULATION OF ELECTRIC MOTORS, ELECTRIC GENERATORS OR DYNAMO-ELECTRIC CONVERTERS , Steuern oder Regeln von elektrischen Motoren, elektrischen Generatoren, dynamoelektrischen Umformern / B62D MOTOR VEHICLES , Motorfahrzeuge / H02H EMERGENCY PROTECTIVE CIRCUIT ARRANGEMENTS , Schutzschaltungsanordnungen / H03K PULSE TECHNIQUE , Impulstechnik