A fast calculation method for permanent magnet eddy current loss of surface-mounted permanent magnet synchronous motor for vehicles

Abstract

The invention provides a fast calculation method for a permanent magnet eddy current loss of a vehicle surface-mount permanent magnet synchronous motor. The influence of phase current harmonics on thepermanent magnet eddy current loss is considered, the quick and accurate calculation of the permanent magnet eddy current loss in a whole working area can be achieved, thus a designer can select appropriate motor structural parameters and electromagnetic parameters during the design process, the permanent magnet eddy current loss is reduced, the irreversible demagnetization of a permanent magnetis avoided, and the normal working of the motor under complex and variable working conditions is ensured. At the same time, the design method of the permanent magnet synchronous motor is improved, andthe design cycle of the permanent magnet synchronous motor is shortened.

Description

technical field [0001] The invention relates to the field of detection and analysis of permanent magnet synchronous motors for vehicles, in particular to a fast calculation technology for permanent magnet eddy current losses of surface-mounted permanent magnet synchronous motors. Background technique [0002] Permanent magnet synchronous motors are widely used in electric vehicle drives because of their excellent characteristics of high power density, high efficiency and easy control. Since the structural parameters and control methods of permanent magnet synchronous motors will cause distortion of the magnetic field inside the permanent magnets, serious eddy current losses will occur inside the permanent magnets of the rotor, reducing the operating efficiency of the motor, and even causing high-temperature demagnetization of the permanent magnets in severe cases. The eddy current loss and its possible influence must be considered in the magneto design process. The current ...

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Problems solved by technology

Since the structural parameters and control methods of permanent magnet synchronous motors will cause distortion of the magnetic field inside the permanent magnets, serious eddy current losses will occur inside the permanent magnets of the rotor, reducing the operating efficiency of the motor, and even causing high-temperature demagnetization of the permanent magnets in severe cases. The eddy current loss and its possible influence must be considered in the design process of the magneto

The current prediction methods for the eddy current loss of permanent magnets in synchronous motors include finite element and analytical methods, but both of these methods have certain limitations: the analytical method only guarantees the rapidity of calculation, but it is based on various assumptions, and the model prediction value exists. Some errors cannot be used to calculate the eddy current loss of permanent magnets under all working conditions; the finite element method only guarantees the accuracy of the calculation. In general, the time required for ordinary computing equipment to solve a working point of a three-dimensional finite element transient model is close to Forty minutes, considering the time harmonics, the finite element calculation time will increase dramatically. Even if an expensive multi-core high-performance computer is used, a solution still takes more than ten minutes. This is because the designer is very proficient in the operation process and Under the premise that the three-dimensional finite element model of the motor is not too complicated

At present, there is still a method for calculating the eddy current loss of the permanent magnet in the full working condition of the surface-mounted permanent magnet synchronous motor based on the assumption that the winding current is sinusoidal. However, this method is relatively rough and ignores the phase current of the stator that will cause serious eddy current loss of the permanent magnet. higher time harmonics

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