Abstract: A method for operating switching elements of an inverter of a vehicle that is driven by way of a three-phase synchronous machine. The inverter has a series circuit of switching elements for the phases. When the vehicle brakes, the synchronous machine is used to set a cycle rate for the operation of the switching elements depending on a frequency of AC phase currents of the synchronous machine. The electrical energy provided by the synchronous machine is fed to a DC voltage intermediate circuit. The cycle rate is set according to the frequency of the AC phase currents, such that it corresponds to the frequency of the respective AC phase currents of the synchronous machine. Zero points of the AC phase currents are determined, and the switching elements are operated to set a predefined phase difference between the respective AC phase current and a respectively associated AC phase voltage.

Abstract: A vehicle includes a drive motor with electrically upstream electric converter, a drive controller generating converter control signals actuating the converter for driving and normal braking operation, and an immobilizer electrically connected between the converter and the drive controller preventing converter control signals which would produce a driving operation of the drive motor from being forwarded to the converter when the vehicle is stopped, in particular at a stop. An alternate regulating device and a monitoring device allow activation of a special braking mode in the presence of an emergency braking command and in the event of which the drive controller is deactivated or at least signal flows of converter control signals of the drive controller to the immobilizer are interrupted, the immobilizer is activated, and converter control signals producing braking operation of the drive motor are transmitted to the converter through the immobilizer by the alternate regulating device.

Abstract: A method for operating switching elements of an inverter of a vehicle that is driven by way of a three-phase synchronous machine. The inverter has a series circuit of switching elements for the phases. When the vehicle brakes, the synchronous machine is used to set a cycle rate for the operation of the switching elements depending on a frequency of AC phase currents of the synchronous machine. The electrical energy provided by the synchronous machine is fed to a DC voltage intermediate circuit. The cycle rate is set according to the frequency of the AC phase currents, such that it corresponds to the frequency of the respective AC phase currents of the synchronous machine. Zero points of the AC phase currents are determined, and the switching elements are operated to set a predefined phase difference between the respective AC phase current and a respectively associated AC phase voltage.

Abstract: A method for controlling a braking torque of a drive system and for braking a vehicle includes in a first state connecting phase connections of a synchronous machine to one another by a changeover apparatus and short circuiting the phase connections such that a first braking torque develops at the synchronous machine. In a second state the phase connections are connected to one another by the changeover apparatus and to a resistance, such that a second braking torque develops at the synchronous machine. The changeover apparatus periodically switches between the first and second states at a switching frequency of 10 Hz or higher to produce a pre-settable braking torque at the synchronous machine, with the changeover between the first state and the second state being controlled by a timing element in an unregulated manner.

Abstract: A method for controlling a braking torque of a drive system and for braking a vehicle includes in a first state connecting phase connections of a synchronous machine to one another by a changeover apparatus and short circuiting the phase connections such that a first braking torque develops at the synchronous machine. In a second state the phase connections are connected to one another by the changeover apparatus and to a resistance, such that a second braking torque develops at the synchronous machine. The changeover apparatus periodically switches between the first and second states at a switching frequency of 10 Hz or higher to produce a pre-settable braking torque at the synchronous machine, with the changeover between the first state and the second state being controlled by a timing element in an unregulated manner.

Abstract: The invention relates to a holding brake for track-bound motor vehicles (1) with the holding brake being realized by means of at least one electric machine (2) which has a rotor and a stator. A control system for the electric machine is hereby provided to so control the operation of the electric machine (2) that the position of the rotor in the stator remains constant when exposed to an external torque. In other words, the electric motor (2) is used as holding brake instead of a pneumatic holding brake. In this way, the holding brake is advantageously not subject to any wear since the holding forces are produced magnetically and not by mechanical forces. In addition, no noise is generated by the use of the holding brake according to the invention. Furthermore, a starting jolt is prevented, when the electric motor (2) used as a holding brake is also used as a drive motor.