Interior PM Rotor Magnet Gradient for Lower Cogging Torque
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing interior permanent magnet synchronous motors experience significant torque ripple due to the change in magnetomotive force represented as a square wave, which affects motor efficiency and performance.
Innovation Solution
The rotor design includes a plurality of poles with magnets arranged such that the magnetomotive force weakens with increasing distance from the magnet center, reducing harmonic components of magnetic flux density and thereby minimizing cogging torque.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Power
If magnets are arranged in a conventional manner with uniform distribution, then the motor can generate sufficient torque, but significant torque ripple occurs due to square wave magnetomotive force
Solution Approach 1:
The patent applies local quality by varying the magnetomotive force strength at different radial positions. Magnets are arranged such that those closer to the magnet center produce stronger magnetomotive force while those farther away produce weaker force. This creates a non-uniform local distribution that transforms the overall magnetomotive force waveform from square wave to sinusoidal, thereby reducing torque ripple while maintaining sufficient torque output.
2Power
If the magnetomotive force is strengthened to improve motor efficiency, then power output increases, but harmonic components of magnetic flux density increase causing higher cogging torque
Solution Approach 1:
The patent changes the parameter distribution of magnetomotive force by position. Instead of uniform magnetomotive force from all magnets, the invention creates a gradient where magnetomotive force strength varies with radial distance from the magnet center. This parameter change transforms the magnetic flux density waveform characteristics, reducing harmonic components while maintaining fundamental wave strength, thus lowering cogging torque without sacrificing motor efficiency.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
This configuration results in a reduced cogging torque and improved motor efficiency, enhancing overall motor performance by minimizing torque ripple.
Implementation Method 1
a magnetomotive force resulting from each magnet becomes weaker with increasing distance from a magnet center
Data Source
AI summary
Provided is a rotor of an interior permanent magnet synchronous motor, including a plurality of poles, wherein each of the plurality of poles includes a plurality of magnets, and the plurality of magnets is provided in such a manner that a magnetomotive force resulting from each magnet becomes weaker with increasing distance from a magnet center.