Abstract: Method for detecting a state of an electric system (150) in a motor vehicle, said electric system (150) comprising a generator unit that includes an electric machine (100) with a rotor winding (110) and a stator winding (120) as well as a rectifier (130) which is connected to the electric machine (100) and via which the electric system (150) is connected to the electric machine (100); in said method, a decision about the current state of the electric system (150), especially about the availability of a battery (200) of the electric system, is made in accordance with an excitation current (IE) flowing through the rotor winding (110) of the electric machine (100).

Abstract: A method for detecting an error in a generator unit which has an electric machine (100) with a rotor winding (110) and a stator winding (120) and a rectifier (130) connected thereto, via which rectifier the electric machine (100) is connected to an electrical system (150) of a motor vehicle, the excitation current (IE) flowing through the rotor winding (110) of the electric machine (100) being plotted and it being concluded that there is an error in the generator unit depending on whether a frequency component (A) of a frequency spectrum of the plot of the excitation current (IE) in a frequency range above a lower speed limit (SW) is larger than a threshold value (S).

Abstract: The invention relates to a method for detecting an error in a generator unit which has an electric machine (100) with a rotor winding (110), a stator winding (120) transformer-coupled to the rotor winding (110), and a rectifier (130) connected to said stator winding, via which the electric machine (100) is connected to an onboard power supply (150) of a motor vehicle, wherein a decision is made, depending on a magnitude of a correlation (K1, K2) between a curve of an excitation current (IE) flowing through the rotor winding (110) of the electric machine (100) and a curve of a voltage drop (UY, UDF) on one side of the transformer, as to whether the error is present or not.

Abstract: A method for determining a speed (nG) of a generator unit which has an electric machine (100) with a rotor winding (110) and a stator winding (120) and a rectifier (130) connected thereto, via which rectifier the electric machine (100) is connected to an electrical system (150) of a motor vehicle, the speed (nG) being determined depending on the plot of an excitation current (IE) flowing through the rotor winding (110) of the electric machine (100). In particular, the speed is determined from a known relationship between the speed, the frequency of the excitation current, the number of pole pairs and optionally the number of phases when there is an error that leads to a constant phase voltage being output.

Abstract: The invention relates to a method for detecting an error in a generator unit which has an electric machine (100) with a rotor winding (110), a stator winding (120) transformer-coupled to the rotor winding (110), and a rectifier (130) connected to said stator winding, via which the electric machine (100) is connected to an onboard power supply (150) of a motor vehicle, wherein a decision is made, depending on a magnitude of a correlation (K1, K2) between a curve of an excitation current (IE) flowing through the rotor winding (110) of the electric machine (100) and a curve of a voltage drop (UY, UDF) on one side of the transformer, as to whether the error is present or not.

Abstract: A method for detecting an error in a generator unit which has an electric machine (100) with a rotor winding (110) and a stator winding (120) and a rectifier (130) connected thereto, via which rectifier the electric machine (100) is connected to an electrical system (150) of a motor vehicle, the excitation current (IE) flowing through the rotor winding (110) of the electric machine (100) being plotted and it being concluded that there is an error in the generator unit depending on whether a frequency component (A) of a frequency spectrum of the plot of the excitation current (IE) in a frequency range above a lower speed limit (SW) is larger than a threshold value (S).

Abstract: A method for determining a speed (nG) of a generator unit which has an electric machine (100) with a rotor winding (110) and a stator winding (120) and a rectifier (130) connected thereto, via which rectifier the electric machine (100) is connected to an electrical system (150) of a motor vehicle, the speed (nG) being determined depending on the plot of an excitation current (IE) flowing through the rotor winding (110) of the electric machine (100). In particular, the speed is determined from a known relationship between the speed, the frequency of the excitation current, the number of pole pairs and optionally the number of phases when there is an error that leads to a constant phase voltage being output.

Abstract: Method for detecting a state of an electric system (150) in a motor vehicle, said electric system (150) comprising a generator unit that includes an electric machine (100) with a rotor winding (110) and a stator winding (120) as well as a rectifier (130) which is connected to the electric machine (100) and via which the electric system (150) is connected to the electric machine (100); in said method, a decision about the current state of the electric system (150), especially about the availability of a battery (200) of the electric system, is made in accordance with an excitation current (IE) flowing through the rotor winding (110) of the electric machine (100).

Abstract: A method for protecting an automotive generator from overheating, in which a predefined limiting characteristic curve, related to a base temperature and describing a maximally allowed excitation current value, is shifted as a function of a calculated temperature, a static offset is ascertained in a first step and a dynamic offset is ascertained in a second step during ascertainment of the calculated temperature, the static offset is ascertained as a function of the excitation current and the dynamic offset is ascertained as a derivation of the excitation current over time.