Synchronous Reluctance Motor Stator Wedges for Lower Torque Ripple
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Synchronous reluctance motors face inefficiencies in generating propulsive force due to high coil current and variation in magnetic permeance, which can lead to increased temperature, torque ripple, and harmonic loss, especially when trying to improve efficiency by narrowing stator-coil intervals or reducing the space between the stator and rotor.
Innovation Solution
Incorporating magnetic wedges that close at least some of the stator slots to maintain current levels and reduce magnetic permeance variation, allowing for improved efficiency without increasing coil current or magnetic flux amplitude.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Use of energy by moving object
If the current flowing in the stator coils is increased to improve efficiency, then the efficiency is improved, but the temperature inside the motor increases
Solution Approach 1:
Magnetic wedges are introduced as intermediary components inserted into the slots of the stator core. These wedges mediate between the stator coils and the rotor by modifying the magnetic field distribution, reducing harmonic magnetic flux, and suppressing torque ripple without requiring increased coil current, thereby improving efficiency while controlling temperature rise
2Use of energy by moving object
If the circumferential intervals of the stator coils are narrowed by increasing the number of slots to improve efficiency, then the efficiency is improved, but the variation of magnetic permeance increases
Solution Approach 1:
Magnetic wedges serve as intermediary elements that stabilize the magnetic permeance in the air gap. By inserting these wedges into the stator slots, the magnetic field distribution is smoothed, reducing the variation of magnetic permeance caused by narrow circumferential intervals between coils, thereby enabling efficient operation with reduced torque ripple
3Use of energy by moving object
If the space between the stator and rotor is narrowed to improve efficiency, then the efficiency is improved, but the variation of magnetic permeance increases
Solution Approach 1:
Magnetic wedges act as intermediary components in the narrowed air gap between stator and rotor. They compensate for the increased magnetic permeance variation caused by the narrow spacing by providing a stabilizing magnetic path, thereby maintaining efficient operation while suppressing harmonic magnetic flux and torque ripple
4Object-generated harmful factors
If the amplitude of harmonic magnetic flux is reduced to suppress torque ripple and electromagnetic excitation force, then the torque ripple is suppressed, but the efficiency may decrease
Solution Approach 1:
The magnetic wedges modify the magnetic circuit parameters by providing additional magnetic paths and altering the reluctance distribution in the air gap. This changes the harmonic content of the magnetic flux without significantly affecting the fundamental flux, thereby suppressing torque ripple while maintaining 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
The magnetic wedges suppress increases in coil current and magnetic permeance variation, enhancing the motor's efficiency while reducing torque ripple and harmonic loss, allowing for a more compact design without overheating.
Implementation Method 1
narrowed circumferential intervals of the stator coils or a narrowed space between the stator and the rotor increases the variation of magnetic permeance of the stator, leading to an expansion of the amplitude of harmonic magnetic flux generated in the stator
Implementation Method 2
the amplitude of harmonic magnetic flux generated in the stator
Implementation Method 3
The salient poles of the rotor are attracted to stator coils disposed in slots provided in the stator in response to energization of the stator coils, resulting in rotation of the rotor
Data Source
AI summary
A synchronous reluctance motor includes a shaft, a rotor, a stator, and multiple magnetic wedges. The stator radially opposes the rotor with a space therebetween. The stator includes a stator core having multiple slots arranged in the circumferential direction and open toward the rotor, and multiple stator coils disposed in the multiple slots. Multiple magnetic wedges close at least some of the multiple slots with the multiple stator coils disposed therein.