Permanent magnet motor rotor permanent magnet temperature real-time monitoring method and model

Abstract

The invention relates to a permanent magnet motor rotor permanent magnet temperature real-time monitoring method and model. The method comprises steps of carrying out the discretization of a motor according to the structure of a permanent magnet motor, and obtaining a plurality of nodes; representing heat transfer between adjacent nodes by thermal resistance to obtain a plurality of thermal resistances; according to the heat transfer path of the permanent magnet motor, the multiple nodes being connected into a thermal network model through thermal resistance and simplified, a target motor equivalent thermal network model being obtained, in the target motor equivalent thermal network model, the heat absorption or heat dissipation capacity of each node being represented by thermal capacity,and the heat source of each node being represented by loss; and calculating a space state matrix of each node in the equivalent thermal network model of the target motor, calculating the working temperature of the permanent magnet and the working temperature of the stator winding by combining a loss temperature bidirectional coupling algorithm, and outputting the working temperature of the permanent magnet. The method can achieve real-time monitoring of the temperature of the permanent magnet of the permanent magnet motor, and guarantees calculation accuracy and reliability of the temperatureof the permanent magnet.

Description

technical field [0001] The invention belongs to the field of new energy electric vehicles, and in particular relates to a method and a model for real-time monitoring of the temperature of a permanent magnet of a rotor of a permanent magnet motor. Background technique [0002] Permanent magnet motors are gradually becoming the motor technology of choice for electric vehicle drive systems due to their high power / torque density, high efficiency, and compact size. When the motor is running, cogging and current harmonics can cause significant eddy current losses in the permanent magnets due to the relatively low resistivity of the rare earth magnets. The eddy current loss causes the temperature of the permanent magnet to rise, which will reduce the performance of the permanent magnet, and even cause irreversible demagnetization of some magnets in severe cases, shortening the service life. Therefore, in order to ensure that the permanent magnet motor operates within the specified...

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Problems solved by technology

However, this technique requires precise measurement equipment and accurate parameters of the motor and inverter. In addition, the nonlinearity of the motor caused by saturation must be considered in the modeling, which will greatly increase the difficulty of modeling and reduce the accuracy of the model.

[0006] In summary, the current technology for monitoring the operating temperature of permanent magnets has the problems of low reliability and accuracy of measurement equipment, difficulty in modeling, and low accuracy of modeling. How to effectively monitor the operating temperature of permanent magnets has become a technical problem that needs to be solved urgently

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