Abstract: A method for operating a fuel pump in a motor vehicle and a fuel pump. A brushless direct current motor arranged in a housing of the fuel pump has a stator and a rotor on a shaft. When the rotor rotates at least one pump stage arranged in the housing is driven via the shaft. The variables of the direct current motor necessary for determining the commutation are fed to a processor in the engine controller of the motor vehicle. The processor generates the electrical signals for the commutation based on these variables according to the field-oriented closed-loop control. These electrical signals are fed to the brushless direct current motor for the commutation.

Abstract: Presented in an apparatus for controlling a brushless DC motor with a permanent magnet arranged on a rotor and a stator with windings. The apparatus includes an observer that is adapted to determine an estimated temperature of the permanent magnet as a function of the temperature of the windings, and determine at least one actuating signal for controlling the DC motor as a function of the estimated temperature of the permanent magnet.

Abstract: Presented in an apparatus for controlling a brushless DC motor with a permanent magnet arranged on a rotor and a stator with windings. The apparatus includes an observer that is adapted to determine an estimated temperature of the permanent magnet as a function of the temperature of the windings, and determine at least one actuating signal for controlling the DC motor as a function of the estimated temperature of the permanent magnet.

Abstract: Below a predetermined threshold value of the rotation speed, a sinusoidal or trapezoidal current is applied to the winding sections of a brushless DC motor. Above the predetermined threshold value of the rotation speed, the brushless DC motor is operated with block commutation. The brushless DC motor thus produces a very uniform torque over a very wide operating range, and can at the same time be designed to be very compact.