Hybrid excitation motor torque ripple optimization method for injecting excitation harmonic current

Abstract

The invention discloses a hybrid excitation motor torque ripple optimization method for injecting excitation harmonic current. The method comprises the steps of respectively generating harmonic induced electromotive force and electromagnetic torque through the injection of the harmonic excitation current so as to offset the specific number of counter electromotive force harmonics and cogging torque and achieve the optimization of the motor torque ripple. The method comprises the steps of firstly, carrying out harmonic analysis on counter electromotive force and cogging torque of the motor; then analyzing a mechanism of weakening counter electromotive force and cogging torque harmonic components of the motor by injecting excitation harmonic current, and deducing expressions of induced electromotive force and electromagnetic torque generated by the harmonic excitation current; and finally, according to the counter electromotive force and the cogging torque which need to be eliminated, obtaining the amplitude and the phase of the harmonic excitation current which is introduced into the excitation winding so as to achieve the purpose of optimizing the motor torque. According to the invention, the complexity of the control system is greatly simplified, and the possible influence of the higher harmonic current on the switch component of the control circuit is avoided.

Description

technical field [0001] The invention relates to the technical field of hybrid excitation motors, in particular to a torque ripple optimization method for hybrid excitation motors based on injection of excitation harmonic currents. Background technique [0002] Hybrid excitation motor not only has the advantages of small size, light weight and high efficiency of permanent magnet motor, but also has the advantages of smooth and adjustable air gap magnetic field of electric excitation motor. It is especially suitable for electric vehicle motor drive system, but hybrid excitation motor has cogging Torque ripple caused by torque and back EMF harmonics affects the performance of the motor. Most of the existing technologies start from changing the structure of the motor, but the reduction of the harmonic distortion rate of the back electromotive force and the cogging torque is limited. [0003] Under the premise of not changing the structure of the motor, the torque ripple of the ...

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Problems solved by technology

[0004] The "Positioning Torque Compensation Method of Magnetic Flux Switching Permanent Magnet Motor Based on Current Harmonic Injection" by Jia Hongyun and other scholars from Southeast University discloses a control strategy that uses current injection method to compensate positioning torque. The method is to inject q-axis harmonic current The generated torque offsets the fundamental wave and various components in the positioning torque. The disadvantage of this method is that it will increase the harmonic component in the compensated armature current, and the harmonic current will cause harmonic eddy current and leakage in the armature winding. Magnetism, causing the motor to heat up, and the high-order harmonic components in it will also affect the motor drive system, increasing the complexity of the control system

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