Abstract: A device and a method for detecting a polarity reversal on a low voltage side of a DC voltage transformer in a dual-voltage vehicle electrical system, particularly in a motor vehicle. A current flow is enabled, in this instance, in a connecting line on the low voltage side of the DC voltage transformer by a controllable switching element, a current is detected in a connecting line on the low voltage side of the DC voltage transformer, with the aid of a current sensor system, the direction of the detected current is evaluated by an evaluation unit and a polarity reversal is detected if the direction of the detected current differs from an expected current direction.

Abstract: A method is provided for current-based detection of an electrical fault in an electrical network of a motor vehicle, the network having at least: one battery, one pulse-controlled inverter, one d.c. voltage converter, and an intermediate circuit associated with the pulse-controlled inverter. The method includes: detecting magnitudes of each a battery current, a d.c. voltage converter current, and an intermediate circuit current; comparing current magnitudes according to provided equations; and checking based on the comparison of whether a specifiable deviation has been exceeded. An alternative method for voltage-based detection of an electrical fault in an electrical network of a motor vehicle includes: detecting magnitudes of each a battery voltage, a d.c. voltage converter voltage, and an intermediate circuit voltage; comparing voltage magnitudes according to provided equations; and checking based on the comparison of whether a specifiable deviation has been exceeded.

Abstract: A method for operating an electrical network, in particular of a hybrid motor vehicle, the network having at least one electrical accumulator, in particular a high-voltage accumulator, at least one electric machine, and at least one inverter controlling the electric machine, the electrical accumulator being electrically disconnected from the network when a malfunction is detected and the inverter being switched to a short-circuit operating mode when a specifiable voltage limit of a network voltage of the network is subsequently exceeded. There is a provision for switching power semiconductors of the inverter in such a way that the driven electric machine induces a voltage and provides it via free-wheeling diodes on the electrical network and the induced voltage is used for operating the electric machine as a generator such that a specifiable network voltage is set by the electric machine.

Abstract: A method and a system for determining the rotor temperature of an electric motor of a hybrid vehicle. In a method for determining the rotor temperature of an electric motor of a hybrid vehicle in which it is possible to reliably determine the rotor temperature using simple means, the rotor temperature of the electric motor being ascertained by measuring an operating parameter of the electric motor during operation of the hybrid vehicle.

Abstract: A device and a method for detecting a polarity reversal on a low voltage side of a DC voltage transformer in a dual-voltage vehicle electrical system, particularly in a motor vehicle. A current flow is enabled, in this instance, in a connecting line on the low voltage side of the DC voltage transformer by a controllable switching element, a current is detected in a connecting line on the low voltage side of the DC voltage transformer, with the aid of a current sensor system, the direction of the detected current is evaluated by an evaluation unit and a polarity reversal is detected if the direction of the detected current differs from an expected current direction.

Abstract: A method for operating an electrical network, in particular of a hybrid motor vehicle, the network having at least one electrical accumulator, in particular a high-voltage accumulator, at least one electric machine, and at least one inverter controlling the electric machine, the electrical accumulator being electrically disconnected from the network when a malfunction is detected and the inverter being switched to a short-circuit operating mode when a specifiable voltage limit of a network voltage of the network is subsequently exceeded. There is a provision for switching power semiconductors of the inverter in such a way that the driven electric machine induces a voltage and provides it via free-wheeling diodes on the electrical network and the induced voltage is used for operating the electric machine as a generator such that a specifiable network voltage is set by the electric machine.

Abstract: A method and a system for determining the rotor temperature of an electric motor of a hybrid vehicle. In a method for determining the rotor temperature of an electric motor of a hybrid vehicle in which it is possible to reliably determine the rotor temperature using simple means, the rotor temperature of the electric motor being ascertained by measuring an operating parameter of the electric motor during operation of the hybrid vehicle.

Abstract: A method for detecting an electrical fault in an electrical network of a motor vehicle, the network having at least one battery, at least one pulse-controlled inverter and at least one d.c. voltage converter, and an intermediate circuit current associated with the pulse-controlled inverter being detected with the aid of an intermediate circuit current sensor. A battery current associated with the battery is detected with the aid of a battery current sensor and a d.c. voltage converter current associated with the d.c. voltage converter is detected with the aid of a d.c. voltage converter current sensor, and the magnitude of the detected intermediate circuit current is compared with an intermediate circuit current determined by calculation with the aid of the battery current sensor and the d.c. voltage converter current sensor to check whether a specifiable deviation has been exceeded.

Abstract: The invention relates to a method for ascertaining the pole wheel position in electrical machines (1), for example rotary current generators with pulse inverters. These electrical machines have a rotor excitation device (2) and a stator (4) provided with inductances (4.1, 4.2, 4.3 or 20, 21, 22). An alternating voltage source (7) is provided on the stator output side, between two stationary terminals (5). By means of first and second switch elements (15, 16), a split into two branches (13 and 14) can be produced, in which the respective branch voltage curves (17, 18) are measured, the superposition of which permits the rotor or pole wheel position (11) to be definitely ascertained.

Abstract: A method for optimizing the starting torque and for reducing the electrical power usage of a starter-generator of an internal combustion engine. The starter-generator is configured as an electrical machine, which is operated using an inverter or an indirect a.c. converter the electrical power Pel being made available by a vehicle battery. Before the imaginary turning point (31) on the torque curve (4) of the starter-generator is reached, the phase current of the electrical machine is limited. The electrical machine is controlled from the point at which a limiting point (32) is reached along the electrical limiting power curve (30) (P=const), such that the electrical power Pel corresponds to that at the stationary operating point (25) of the electrical machine.

Abstract: The invention relates to a method for determining the position of a rotating component of a claw pole machine (1), which is operated in the R-S-T-system and whose regulation requires the transformation of the stator values from the R-S-T-system into the d, q-system and vice versa. The claw pole machine (1) as an overall system (15) is divided into a non-detectable subsystem (18) and a detectable subsystem (19), which contains a filter element (20). The filter element (20) contained in the detectable subsystem (19, 29) supplies the output values (17).

Abstract: A method for optimizing the starting torque and for reducing the electrical power usage of a starter-generator of an internal combustion engine. The starter-generator is configured as an electrical machine, which is operated using an inverter or an indirect a.c. converter the electrical power Pel being made available by a vehicle battery. Before the imaginary turning point (31) on the torque curve (4) of the starter-generator is reached, the phase current of the electrical machine is limited. The electrical machine is controlled from the point at which a limiting point (32) is reached along the electrical limiting power curve (30) (P=const), such that the electrical power Pel corresponds to that at the stationary operating point (25) of the electrical machine.