Asymmetric PM-Assisted Synchronous Reluctance Motor for Low Torque Ripple
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Solution Overview
Problem
Existing electric motors in electric cars face issues of low efficiency, noise, and demagnetization due to the use of ferrite permanent magnets, and high production costs due to reliance on rare earth materials.
Innovation Solution
A permanent magnet assisted synchronous reluctance motor design with specific slot arrangements and permanent magnet configurations that reduce torque ripple, improve efficiency, and suppress electromagnetic noise, utilizing a stator and rotor structure with oppositely arranged ends of permanent magnet slots and stator teeth.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If ferrite permanent magnets are used in synchronous reluctance motor, then production cost is reduced, but motor efficiency decreases and demagnetization occurs easily
Solution Approach 1:
The motor design segments the magnetic circuit into specific regions by creating asymmetric flux barriers in the rotor. The rotor includes multiple flux barriers with different positions and dimensions relative to the stator teeth, segmenting the magnetic flux paths to optimize performance while using ferrite magnets
Solution Approach 2:
The patent applies asymmetry by designing flux barriers that are positioned asymmetrically relative to the stator teeth. The first flux barrier is positioned at a different angular location and has different dimensions compared to the second flux barrier, creating asymmetric magnetic reluctance paths that improve motor efficiency and reduce torque ripple while using cost-effective ferrite permanent magnets
2Reliability
If rare earth permanent magnets are used to achieve high efficiency and high power density, then motor performance is improved, but production cost increases significantly
Solution Approach 1:
The patent replaces expensive rare earth permanent magnets with cheaper ferrite permanent magnets. By redesigning the magnetic circuit with asymmetric flux barriers and optimized pole structures, the patent achieves acceptable motor performance using the cheaper ferrite material, thereby reducing production cost while maintaining reasonable efficiency
3Ease of manufacture
If symmetric flux barrier arrangement is used in synchronous reluctance motor, then manufacturing is simplified, but torque ripple increases
Solution Approach 1:
The patent directly applies asymmetry by positioning flux barriers asymmetrically relative to stator teeth. The first flux barrier is located at a different angular position and has different dimensions than the second flux barrier, creating asymmetric magnetic reluctance that reduces torque ripple and improves motor performance
4Manufacturing precision
If permanent magnet slots are aligned with stator teeth, then manufacturing precision is reduced, but electromagnetic noise increases
Solution Approach 1:
The asymmetric positioning of flux barriers relative to stator teeth creates varying magnetic reluctance paths that disrupt the alignment between rotor permanent magnet slots and stator teeth. This asymmetric design reduces electromagnetic noise by preventing direct alignment while maintaining manufacturing feasibility
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
The motor design effectively reduces torque ripple, enhances efficiency, and suppresses electromagnetic noise, improving the user experience and reducing production costs by minimizing reliance on rare earth materials.
Implementation Method 1
a permanent magnet assisted synchronous reluctance motor design with specific slot arrangements and permanent magnet configurations that reduce torque ripple, improve efficiency, and suppress electromagnetic noise
Implementation Method 2
a first end of at least one of the plurality of permanent magnet slots and an end of one of the plurality of stator teeth are arranged oppositely
Implementation Method 3
a permanent magnet assisted synchronous reluctance motor design with specific slot arrangements and permanent magnet configurations that reduce torque ripple, improve efficiency, and suppress electromagnetic noise
Data Source
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AI summary
The present disclosure provides a permanent magnet assisted synchronous reluctance motor and an electric car having the same. The permanent magnet assisted synchronous reluctance motor includes: a stator body, wherein a plurality of stator teeth are provided on an inner circumferential surface of the stator body, and a stator slot is formed between two adjacent stator teeth; a rotor body disposed within the stator body and opened with a group of permanent magnet slots, which include a plurality of permanent magnet slots, wherein a first end of at least one of the plurality of permanent magnet slots and an end of one of the plurality of stator teeth are arranged oppositely, and a second end of the permanent magnet slot and the stator slot formed by two adjacent stator teeth among remaining stator teeth are arranged oppositely. The permanent magnet assisted synchronous reluctance motor using this structure can effectively reduce the torque ripple of the electric motor, effectively improve the efficiency of the motor of the permanent magnet assisted synchronous reluctance motor, suppress the electromagnetic noise of the motor and improve the operation experience of the user.