Rotor permanent magnet temperature rise estimation method and system of six-phase motor

Abstract

The invention discloses a rotor permanent magnet temperature rise estimation method and system for a six-phase motor, and the method comprises the steps: injecting currents with equal amplitudes and opposite polarities into a harmonic plane in a mathematical model of the six-phase motor, and obtaining a motor equation for eliminating the resistance R of the motor through the conversion of a fundamental plane and the harmonic plane; the flux linkage of the permanent magnet at the initial temperature T0 and the temperature T (t) at any t moment is obtained through calculation; and determining the relation between the permanent magnet flux linkage and the temperature rise, and substituting the relation into the obtained permanent magnet flux linkage under different working conditions to obtain the temperature rise of the rotor permanent magnet. According to the method, the rotor permanent magnet temperature can be accurately estimated for the six-phase motor, the method is more direct, the estimated result is more accurate, the extreme condition of high-temperature demagnetization can be avoided, and the method is easy to implement, low in implementation cost and suitable for popularization and application. Misjudgment caused by indirect observation or inaccurate measured data of the temperature sensor is avoided, and the whole monitoring process is easy to implement.

Description

technical field [0001] The invention relates to a monitoring technology for temperature rise of a permanent magnet of a motor rotor, in particular to a method and system for estimating the temperature rise of a rotor permanent magnet of a six-phase motor. Background technique [0002] In recent years, with people's emphasis on the reliability of key power components, six-phase motors have become more and more widely used. Six-phase permanent magnet motor has high power density, high performance, high efficiency, and good fault tolerance performance, which can meet the reliability and fault tolerance requirements of the motor system under special working conditions, and has attracted more and more attention. [0003] Since the six-phase permanent magnet motor works in a harsh environment, its stator winding will generate heat during operation, and its rotor permanent magnet may undergo irreversible demagnetization under the action of thermal stress, which seriously affects th...

AI Technical Summary

Problems solved by technology

The method of observing the resistance value of the stator winding is an indirect method, which cannot directly observe the permanent magnet of the rotor, and there may be certain errors that cannot reflect the actual temperature of the permanent magnet of the rotor.

By injecting the fundamental wave current into the winding of the motor, specific current and voltage signals are extracted from it. Since it is the harmonic injected into its fundamental wave circuit, it will cause torque fluctuations during the operation of the motor. Affect the normal operation of the motor

[0005] In summary, the existing methods for estimating the temperature of permanent magnets in motors are used in six-phase motors, and there are technical problems such as inaccurate temperature estimation, interference, and poor applicability.

Images