Method and device for detecting a malfunction of an electric machine

Abstract

The invention relates to a method for detecting a malfunction of an electric machine, a first variable (isq) influencing the torque (M) of the electric machine (1) being modulated. In order to reliably detect the malfunction of an electric machine and to prevent an associated unwanted torque or power output of the electric machine, a second variable ([psi]p) influencing the torque of the electric machine is modulated, the two variables ([psi]p, isq) influencing the torque (M) cancelling each other out, when the electric machine functions properly, with respect to their effect onto a parameter of the electric machine (1), especially a torque (M), a speed, an electric parameter and / or a magnetic parameter, while it is concluded that there is a malfunction in the event of the lack of such a cancellation.

Description

technical field

[0001] The invention relates to a method for identifying fault characteristics of an electric machine, wherein a first variable influencing the torque of the electric machine is modulated, and to a device for carrying out the method. Background technique

[0002] The torque of a motor can be affected by several independent variables. No suitable measuring system for directly determining the torque output or the power output of the electric machine is usually present in the drive train of a motor vehicle. For example, the measurement of the drive shaft torque is omitted for cost reasons. The undesired torque output or power output of the electric machine cannot therefore be determined directly. Especially in electric vehicles or hybrid vehicles, there can be a force fit between the electric machine of the vehicle and the drive wheels even when the vehicle is at a standstill. An undesired torque output or power output of the electric machine, for example due...

Examples

Embodiment Construction

[0031] figure 1 The embodiment of the present invention is shown by taking a separately excited three-phase synchronous motor 1 as an example, which is used to drive an electric vehicle. The windings of the stator, not shown further, are called phase u, phase v and phase w and are shown in a very simplified manner. The coil axes of these windings are each rotated by 120 degrees relative to each other. The field winding 2 through which the current in the rotor 3 flows produces the rotor flux Ψ p . The driver of the motor vehicle or a safety system or driver assistance system of the motor vehicle specifies the desired torque M Soll . Desired torque M Soll During the switching process of the automated gear, it is influenced by the automated gear.

[0032] The field-oriented view of the three-phase electric machine 1 is based on the principle of space vectors. This relationship can be simplified when looking at a standard orthogonal d-q coordinate system operating in synchr...

technical field

[0001] The invention relates to a method for identifying fault characteristics of an electric machine, wherein a first variable influencing the torque of the electric machine is modulated, and to a device for carrying out the method. Background technique

[0002] The torque of a motor can be affected by several independent variables. No suitable measuring system for directly determining the torque output or the power output of the electric machine is usually present in the drive train of a motor vehicle. For example, the measurement of the drive shaft torque is omitted for cost reasons. The undesired torque output or power output of the electric machine cannot therefore be determined directly. Especially in electric vehicles or hybrid vehicles, there can be a force fit between the electric machine of the vehicle and the drive wheels even when the vehicle is at a standstill. An undesired torque output or power output of the electric machine, for example due...

Examples

Embodiment Construction

[0031] figure 1 The embodiment of the present invention is shown by taking a separately excited three-phase synchronous motor 1 as an example, which is used to drive an electric vehicle. The windings of the stator, not shown further, are called phase u, phase v and phase w and are shown in a very simplified manner. The coil axes of these windings are each rotated by 120 degrees relative to each other. The field winding 2 through which the current in the rotor 3 flows produces the rotor flux Ψ p . The driver of the motor vehicle or a safety system or driver assistance system of the motor vehicle specifies the desired torque M Soll . Desired torque M Soll During the switching process of the automated gear, it is influenced by the automated gear.

[0032] The field-oriented view of the three-phase electric machine 1 is based on the principle of space vectors. This relationship can be simplified when looking at a standard orthogonal d-q coordinate system operating in synchr...

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