Abstract: In an active converter that is connected to an electric machine, in which arresting circuits for activating a voltage arrest beginning at a first point in time are provided, and which is also configured for activating a load shedding reaction only when activation conditions are fulfilled beginning at a second point in time, the activation conditions include determining that the voltage arrest is still activated at the second point in time, that a voltage potential has not yet fallen below the first threshold value, and/or that a value that indicates a current flowing through at least one phase connection is above a third threshold value.

Abstract: An active converter connected to an electric machine, including arresting circuits to activate a voltage arresting function from a first point-in-time, and which is configured to only activate a load dump reaction upon activation conditions from a second point-in-time, the activation conditions include that it is determined that at the second point-in-time, a supply-side voltage potential applied to an exciter winding of the electric machine is between the voltage potential applied at the first DC voltage terminal and a ground potential, if the exciter winding is disconnected from the voltage potential of the vehicle electrical system voltage and/or a current flowing through the exciter winding is below a current threshold value and/or after an initial activation of a load dump reaction, after which further load dump reactions were activated, more than a predefined period of time has elapsed and/or more than a predefined number of load dump reactions were activated.

Abstract: A method for identifying electrical faults in a generator assemblage, in particular of a motor vehicle, which assemblage includes a generator having a generator regulator and a rectifier having rectifier elements, the method encompassing ascertaining, in the context of at least one excitation current value of an excitation current through an excitation winding of the generator, at least one respective parameter that corresponds to a current conduction time proportion of at least one of the rectifier elements, and determining that an electrical fault exists if the at least one parameter deviates by more than a predetermined amount from an associated expected value. Also described is an apparatus for implementing the method.

Abstract: A method for controlling a multi-phase electric machine, operable at least in generator mode, whose phase terminals in an active bridge rectifier are respectively connected, via addressable first current valves capable of being switched on and shut off, to a first DC voltage terminal and via second current valves to a second DC voltage terminal. The method includes: in a generator mode of the electric machine after occurrence of a load dump, repeatedly initiating and discontinuing phase short circuits of the phase terminals via the first current valves. A magnitude characterizing a natural frequency of the electric machine is ascertained, and the first current valves are addressed with a switching frequency in order to initiate and discontinue the phase short circuits on the basis of the magnitude characterizing the natural frequency of the electric machine.

Abstract: A vehicle electrical system includes: an active bridge rectifier which is connected to a generator via multiple phase terminals, and having terminals on the direct voltage side; a unit for recognizing load shedding at the active bridge rectifier and short-circuiting the phase terminals in a clocked manner, as the result of which a pulsed current is fed to the vehicle electrical system; a vehicle electrical system capacitor configured for smoothing the pulsed current; and a voltage limiting unit configured for clipping a voltage between the terminals of the bridge rectifier on the direct voltage side to a predefined maximum voltage.

Abstract: A method is described for activating a multiphase machine that has a link circuit equipped with a link circuit capacitor, phase windings, and one high-side switch and one low-side switch per phase. The switches associated with the individual phases have control signals applied to them by a control unit. The control unit provides, in successive activation cycles, pulse-shaped control signals for the switches, the pulse widths and pulse onsets of which are respectively varied within an activation cycle in such a way that the link circuit current is reduced.

Abstract: A method for activating a rectifier having active switching elements in the event of a load dump, the active switching elements being activated during the voltage clamping in such a way that the clamp voltage in at least one switching branch complies with a signal form predefined as a function of time within at least one half-period of the current to be rectified.

Abstract: A method for operating an active rectifier including a multitude of controllable semiconductor switching elements, in which a switch is carried out between a first control mode and a second control mode for controlling the semiconductor switching elements, and vice versa, the semiconductor switching elements being controlled with a first switching time in the first control mode and with a second switching time in the second control mode, the second switching time being greater than the first switching time.

Abstract: A method for operating a motor vehicle electrical system which includes an electric machine, and an active bridge rectifier connected to the electric machine via phase connections. After the bridge rectifier has been operated at least once in a short circuit operating mode, a determination is made, based on at least one feature of a signal which characterizes a voltage that drops between the direct voltage terminals of the bridge rectifier, whether the signal has exceeded the upper threshold value due to a cable break at at least one of the direct voltage terminals. If so, the bridge rectifier is subsequently operated in the short circuit operating mode for an extended period of time, and/or a control signal having a second switching time greater than that in the first method phase is used for controlling the active switching elements.

Abstract: A half bridge for an active rectifier having an alternating-voltage connection, a positive direct-voltage connection, as well as a ground connection, a first switch element connecting the alternating-voltage connection to the ground connection; a second switch element connecting the alternating-voltage connection to the positive direct-voltage connection, a first control element being connected to the first switch element for switching the first switch element; a connection of a first capacitor being connected to a voltage supply connection of the first control element; the positive direct-voltage connection being connected via a first diode in the forward direction to the one connection of the first capacitor; the first capacitor being connected in parallel to a series connection of the first switch element and the second switch element.

Abstract: A motor vehicle electrical system which includes an electric machine, an active bridge rectifier, and at least one control device, the at least one control device being configured for converting an alternating voltage which is output by the electric machine at a number of phase connections into a direct voltage by controlling active switching elements of the bridge rectifier. An arrangement is provided configured for initiating a short circuit of at least two of the phase connections as soon as a signal characterizing the direct voltage exceeds an upper threshold value, and for deactivating the short circuit as soon as the signal characterizing the direct voltage subsequently falls below a lower threshold value. An evaluation device is provided configured for detecting a value of the direct voltage, for filtering the detected value, and for providing the filtered value as the signal characterizing the direct voltage.

Abstract: A rectifier module for an active bridge rectifier having two switching elements, connected in series between two end terminals, and between which a center tap is formed, and a control circuit including a monitoring unit, a synchronization unit, and a control unit, the monitoring unit detecting a measuring voltage and outputting a request signal when the measuring voltage exceeds an upper threshold value. The synchronization unit outputs a synchronization signal to a synchronization terminal as long as the monitoring unit outputs the request signal, and otherwise to monitor the synchronization terminal for a synchronization signal. The control unit switches one of the two switching elements into a conductive state at least in sections during an activation period of time, when the monitoring unit outputs the request signal and/or when the synchronization signal is detected and is optionally recognized as valid by the monitoring.

Abstract: A control unit for an electric machine. The control unit has a processing unit and a power output stage connected to the processing unit. The power output stage is connected to outputs of the control unit for stator coils of a stator of the electric machine. The processing unit is designed to supply current to the power output stage for generating a stator field, in particular a rotating magnetic field. The control unit comprises an electrical energy store, in particular an intermediate circuit capacitor or accumulator, connected to the power output stage. The control unit includes an input for a control signal, for example a temperature signal. The processing unit is preferably designed to actuate the power output stage as a function of the temperature signal such that the energy store can be heated by a current application pattern generated by the power output stage.

Abstract: A bridge rectifier having AC voltage terminals, two DC voltage terminals, and a number of half-bridges corresponding to the number of AC voltage terminals. Each half-bridge has two activatable switching elements, connected in series between the DC voltage terminals and between which one of the AC voltage terminals is connected in each case. Each half-bridge includes a control circuit configured to detect an output voltage applied between the DC voltage terminals and switch a first switching element of the two switching elements of the particular half-bridge to be conductive by activation using a first control signal until the output voltage falls below a lower threshold value, after it has previously exceeded an upper threshold value, and to activate it in a clocked manner by activation using a second control signal, until the output voltage exceeds the upper threshold value, after it has previously fallen below the lower threshold value.

Abstract: A rectifier bridge circuit is described for rectifying the phase voltage generated by a generator, including a positive half-bridge having multiple rectifier elements and a negative half-bridge having multiple rectifier elements. The rectifier elements each have a controllable switch having a diode connected in parallel. A control circuit is provided for switching the switches on and off. The switch-on time tswitch on setpoint and/or the switch-off time tswitch off setpoint of the switch is/are computed based on a characteristic map or a mathematical function.

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 is described for controlling a multiphase machine which is connected to a battery, the multiphase machine having a DC link which is provided with a DC link capacitor, phase windings, and a high side switch and a low side switch for each phase. The switches associated with the individual phases are controlled by a control unit in such a way that sinusoidal phase currents are predefined, at least one phase current is connected at any point in time in each control cycle, and a fixed, pulsed control pattern is present for each control cycle. The control widths of the actuating signals associated with the phases are constant in the pulsed control pattern. The control pulses associated with the individual phases are predefined in such a way that the DC link current which arises is minimized.

Abstract: In a method for determining current in a polyphase machine connected to a DC voltage source, a DC link is provided with a DC-link capacitor and, per phase, a high-side switch and a low-side switch. A measurement of the voltage curve across the DC-link capacitor is undertaken. The current of the DC voltage source and/or one or a plurality of phase currents are/is determined from the measured voltage curve.

Abstract: A method for operating a power converter having at least one power converter half-bridge, in which a controllable switching element and a freewheeling diode connected parallel thereto and in the blocking direction are provided respectively between a first direct voltage terminal and an alternating voltage terminal as well as between the alternating voltage terminal and a second direct voltage terminal. The switching elements of the at least one half-bridge are controlled in alternating fashion and in each case interrupted by controlling pauses. The duration of the controlling pauses is set on the basis of a determined voltage drop at at least one of the freewheeling diodes.

Abstract: A method for controlling a multiphase machine which is connected to a direct current voltage source. The machine has a DC link which is provided with a DC link capacitor, phase windings, and a high side switch and a low side switch for each phase. The switches associated with the individual phases are acted on by control signals from a control unit. For reducing the DC link current, the control unit provides block-shaped control signals for the switches associated with the individual phases in such a way that trapezoidal or pulsed phase currents are predefined, at least one phase current is connected at any point in time in each control cycle, and the value of the amplitude ratio of the predefined phase currents is selected in such a way that the connected phase currents correspond to the instantaneous current of the direct current voltage source.