Abstract: The invention relates to an overvoltage arrester for an electrical drive, especially a drive for a motor vehicle. The overvoltage arrester is designed to be connected to an on-board power supply system of a motor vehicle. The overvoltage arrester is designed to reduce any overvoltage produced in the on-board power supply system when a load is switched off. According to the invention, the overvoltage arrester is connected to a control unit for an electronically commutated electrical machine. The overvoltage arrester has an input for an on-board power supply system and is designed to detect when a pre-determined voltage value is exceeded and to produce an overvoltage signal depending on whether the voltage value is exceeded. The control unit is designed to transfer the electrical machine from an operating mode in which the machine generates power to an at least partial power-loss mode or to a mode in which it operates as a motor.

Abstract: A method for operating an electric machine having a power inverter, which is electrically connected to a relative ground potential, and a ground differential voltage between the relative ground potential and a reference ground potential is monitored, and if the ground differential voltage reaches an upper limit value, the electric machine is operated in a current-delivering operating state, and if the ground differential voltage reaches a lower limit value, the electric machine is operated in a non-current-delivering operating state.

Abstract: A multi-voltage electrical system of a motor vehicle includes first and second subsystems operable at operating voltages, where a current is selectively and alternatively feedable from the first subsystem into the second subsystem and from the second subsystem into the first subsystem, and an electrical consumer is coupleable to and decoupleable from the first subsystem. A method for operating the system includes, responsive to a failure or lack of an attenuator, implementing a special operating mode in which negative and positive sudden load variations caused by coupling or decoupling of the electrical consumer is counteracted by, respectively, feeding current from the second subsystem into the first subsystem or vice versa, in each case over a respective feed time period.

Abstract: In a method for operating a starter of a vehicle, a position of a starter pinion is detected, and an advance of the starter pinion is regulated as a function of the detected position. For example, the advance during the meshing of the starter pinion with a starter ring gear of a drive motor of the vehicle is regulated.

Abstract: A method for operating an electric machine having a power inverter, which is electrically connected to a relative ground potential, and a ground differential voltage between the relative ground potential and a reference ground potential is monitored, and if the ground differential voltage reaches an upper limit value, the electric machine is operated in a current-delivering operating state, and if the ground differential voltage reaches a lower limit value, the electric machine is operated in a non-current-delivering operating state.

Abstract: A method for operating a power supply unit for an electrical system of a motor vehicle, the power supply unit having an electric generator having a stator having a stator winding and a rotor having a rotor winding, as well as a field current controller assigned to the rotor winding for selecting the setpoint of the current flowing through the rotor winding; the electric generator being set into rotation without a current being specified by the rotor winding, thereby generating a starting voltage; at least one component of the power supply unit or of the vehicle electrical system being energized by the starting voltage.

Abstract: A diagnostic device is provided for a multi-voltage electrical system of a motor vehicle which has a first subnetwork acted on by a first voltage and a second subnetwork acted on by a second voltage, the first voltage being higher than the second voltage, and the first and the second subnetwork having a shared ground connection. The diagnostic device includes a second ground connection, a measuring unit configured to measure a current flow via the second ground connection, and a diagnostic unit configured to diagnose a disturbance in the shared ground connection and/or in the second ground connection on the basis of the measured current flow via the second ground connection as a function of at least one operating state of the vehicle electrical system.

Abstract: A method and a circuit system for operating an electric machine are presented. The method is carried out in particular in a starting phase, a current being limited using a controllable resistor, the controllable resistor being implemented by at least one semiconductor switch, which is controlled using a clocked signal, and the signal being set in such a way that in shutdown phases, the at least one semiconductor switch is not completely shut down.

Abstract: A method for operating a power supply unit for an electrical system of a motor vehicle, the power supply unit having an electric generator having a stator having a stator winding and a rotor having a rotor winding, as well as a field current controller assigned to the rotor winding for selecting the setpoint of the current flowing through the rotor winding; the electric generator being set into rotation without a current being specified by the rotor winding, thereby generating a starting voltage; at least one component of the power supply unit or of the vehicle electrical system being energized by the starting voltage.

Abstract: The invention relates to an overvoltage arrester for an electrical drive, especially a drive for a motor vehicle. The overvoltage arrester is designed to be connected to an on-board power supply system of a motor vehicle. The overvoltage arrester is designed to reduce any overvoltage produced in the on-board power supply system when a load is switched off. According to the invention, the overvoltage arrester is connected to a control unit for an electronically commutated electrical machine. The overvoltage arrester has an input for an on-board power supply system and is designed to detect when a pre-determined voltage value is exceeded and to produce an overvoltage signal depending on whether the voltage value is exceeded. The control unit is designed to transfer the electrical machine from an operating mode in which the machine generates power to an at least partial power-loss mode or to a mode in which it operates as a motor.

Abstract: A diagnostic device is provided for a multi-voltage electrical system of a motor vehicle which has a first subnetwork acted on by a first voltage and a second subnetwork acted on by a second voltage, the first voltage being higher than the second voltage, and the first and the second subnetwork having a shared ground connection. The diagnostic device includes a second ground connection, a measuring unit configured to measure a current flow via the second ground connection, and a diagnostic unit configured to diagnose a disturbance in the shared ground connection and/or in the second ground connection on the basis of the measured current flow via the second ground connection as a function of at least one operating state of the vehicle electrical system.

Abstract: A multi-voltage electrical system of a motor vehicle includes first and second subsystems operable at operating voltages, where a current is selectively and alternatively feedable from the first subsystem into the second subsystem and from the second subsystem into the first subsystem, and an electrical consumer is coupleable to and decoupleable from the first subsystem. A method for operating the system includes, responsive to a failure or lack of an attenuator, implementing a special operating mode in which negative and positive sudden load variations caused by coupling or decoupling of the electrical consumer is counteracted by, respectively, feeding current from the second subsystem into the first subsystem or vice versa, in each case over a respective feed time period.

Abstract: A motor vehicle electrical system includes at least one first subsystem and one second subsystem having different voltage levels. The first subsystem has a generator system, which is designed to supply the first subsystem with a first subsystem voltage, the generator system having an electrically excited generator including an exciter winding and a generator governor for controlling the exciter winding. The exciter winding is connected to the second subsystem and supplied with a second subsystem voltage from the second subsystem.

Abstract: A method and a circuit system for operating an electric machine are presented. The method is carried out in particular in a starting phase, a current being limited using a controllable resistor, the controllable resistor being implemented by at least one semiconductor switch, which is controlled using a clocked signal, and the signal being set in such a way that in shutdown phases, the at least one semiconductor switch is not completely shut down.

Abstract: In a method for operating a starter of a vehicle, a position of a starter pinion is detected, and an advance of the starter pinion is regulated as a function of the detected position.