Consequent-Pole Rotor Assembly With Air Slots for Torque Stability
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Solution Overview
Problem
Consequent-pole permanent magnet synchronous motors experience significant torque fluctuation due to the asymmetry of adjacent magnetic pole structures, limiting their further popularization and application.
Innovation Solution
A rotor assembly with a specific design featuring iron core mounting grooves and air slots that distribute permanent magnets along the circumferential direction, adjusting magnetic flux leakage and orientation to stabilize torque output, including first and second air slots that gradually increase in width and are strategically positioned to optimize magnetic line distribution.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If consequent-pole permanent magnet synchronous motor is used to reduce the number of permanent magnets, then cost is reduced, but torque fluctuation increases
Solution Approach 1:
The rotor is segmented into multiple magnetic pole pairs, with each pair consisting of a permanent magnet pole and a consequent pole. This segmentation allows the magnetic flux to be distributed more evenly around the rotor circumference, reducing torque ripple while maintaining the cost advantage of using fewer permanent magnets.
Solution Approach 2:
The patent introduces local quality variations through different air slot configurations (first air slots in permanent magnet pole regions and second air slots in consequent-pole regions) and varying circumferential widths of magnetic pole regions. These local modifications optimize magnetic flux distribution at critical locations, thereby reducing overall torque fluctuation.
2Ease of manufacture
If conventional consequent-pole structure is used, then manufacturing is simpler, but magnetic flux distribution is asymmetric causing torque fluctuation
Solution Approach 1:
The patent intentionally introduces controlled asymmetry through the first and second air slots with different configurations, and varying circumferential widths of magnetic pole regions. This controlled asymmetry compensates for the inherent asymmetry in consequent-pole structures, achieving more symmetric magnetic flux distribution and reduced torque fluctuation while maintaining manufacturing simplicity.
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 design significantly reduces torque fluctuation and increases the utilization ratio of permanent magnets, leading to a more stable and efficient output torque, as demonstrated by the comparison with prior art motors.
Implementation Method 1
a plurality of permanent magnets accommodated respectively in the plurality of mounting grooves, wherein magnetic poles of the plurality of permanent magnets facing the outer edge of the iron core are the same
Implementation Method 2
adjusting magnetic flux leakage and orientation to stabilize torque output
Data Source
AI summary
The present disclosure relates to a rotor assembly and a consequent-pole motor, and the rotor assembly includes an iron core and a plurality of permanent magnets. The iron core is provided with a plurality of mounting grooves for accommodating permanent magnets distributed along a circumferential direction of the iron core. One side of each of the mounting grooves adjacent to an end of an outer edge of the iron core is provided with a second air slot which is located in a consequent-pole region. The second air slot is communicated with the mounting groove. The second air slot can, on one hand, prevent magnetic lines emitted from the permanent magnet from short-circuiting through an end of the permanent magnet, so as to decrease the magnetic flux leakage, and on the other hand, adjust an orientation of the magnetic lines in the consequent-pole region, so as to weaken torque fluctuation.