Segmented Rotor Core with Magnetic Barriers for Torque Ripple Reduction
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Permanent magnet embedded type electrical rotating machines with skew structures face challenges in reducing cogging torque and torque ripple due to short-circuiting of magnetic flux, leading to a reduction in effective magnetic flux.
Innovation Solution
The implementation of a rotor core structure with alternating flux barrier and effective magnetic flux portions, where the flux barrier portions are magnetically saturated between adjacent magnetic poles, and non-magnetic substance layers prevent short-circuiting between rotor cores, ensuring that magnetic poles with different orientations do not overlap axially, thereby maintaining effective magnetic flux.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If a skew structure is adopted to reduce cogging torque and torque ripple, then the smoothness of rotation is improved, but magnetic flux short-circuiting occurs between rotor core blocks, reducing effective magnetic flux
Solution Approach 1:
The rotor core is divided into multiple rotor core blocks arranged in the axial direction. Each block contains permanent magnets arranged with skew structure. By segmenting the rotor core, the patent maintains the skew structure for reducing cogging torque while introducing magnetic barrier portions to prevent flux short-circuiting between blocks, thus resolving the contradiction between rotation smoothness and effective magnetic flux quantity.
Solution Approach 2:
Magnetic barrier portions are introduced as intermediary elements between adjacent rotor core blocks. These barrier portions act as magnetic flux barriers that prevent the short-circuiting of magnetic flux between blocks with different polarities. The magnetic barrier portions serve as mediators that maintain the beneficial skew structure while blocking the harmful flux leakage, thereby preserving effective magnetic flux.
2Device complexity
If N-pole and S-pole overlap in the axial direction between adjacent rotor core blocks, then the skew structure is simplified, but magnetic flux forms short-circuit loops inside the rotor, reducing torque
Solution Approach 1:
The rotor core is segmented into multiple blocks along the axial direction, with each block containing permanent magnets arranged with skew structure. This segmentation allows the maintenance of simplified skew structure within each block while preventing flux short-circuiting between blocks through magnetic barrier portions, thus resolving the contradiction between structure simplicity and torque generation.
Solution Approach 2:
Magnetic barrier portions are positioned between adjacent rotor core blocks to act as intermediaries that block magnetic flux from forming short-circuit loops. These barrier portions prevent direct magnetic coupling between N-pole and S-pole of adjacent blocks, thereby eliminating the torque reduction caused by flux short-circuiting while maintaining the simplified skew structure arrangement.
3Quantity of substance
If a non-magnetic substance layer is interposed between rotor core blocks to suppress magnetic flux short-circuiting, then effective magnetic flux is preserved, but the structure complexity increases
Solution Approach 1:
The magnetic barrier portions are merged with the rotor core blocks, forming an integrated structure where the barrier portions are part of the rotor core assembly. This merging approach preserves effective magnetic flux by preventing flux short-circuiting while avoiding the need for separate non-magnetic substance layers, thus reducing structure complexity compared to using distinct non-magnetic interposing layers.
Solution Approach 2:
The rotor core blocks and magnetic barrier portions are constructed using composite material arrangements where ferromagnetic materials form the rotor core blocks and magnetic barriers, eliminating the need for non-magnetic substance layers. This composite structure achieves flux preservation while maintaining structural simplicity through the use of magnetically functional materials integrated into the rotor core design.
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 effectively reduces cogging torque and torque ripple, minimizing the reduction in effective magnetic flux and enhancing the rotational efficiency of the electrical rotating machine.
Implementation Method 1
The plurality of flux barrier portions are magnetically saturated between the magnetic poles of the permanent magnet portions adjacent to each other in the circumferential direction
Implementation Method 2
a plurality of permanent magnet portions which are embedded in the first rotor core and the second rotor core
Implementation Method 3
The rotor includes a non-magnetic substance layer which is interposed between the first rotor core and the second rotor core
Data Source
AI summary
A rotor of an electrical rotating machine includes a first rotor core, a second rotor core which overlaps the first rotor core in an axial direction, a non-magnetic substance layer which is interposed between the rotor cores, and a plurality of permanent magnet portions which are embedded in each rotor core. Each of the rotor cores includes a plurality of flux barrier portions and a plurality of effectual magnetic flux portions which are alternately arranged on an outer circumferential surface thereof. The flux barrier portion of the first rotor core overlaps both of a portion of the flux barrier portion of the second rotor core and a portion of the effectual magnetic flux portion of the second rotor core in the axial direction such that, in the adjacent rotor cores, the effectual magnetic flux portions do not overlap each other in the axial direction.