Asymmetric Stator Tooth Layout for Miniaturized Three-Phase Motors
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Solution Overview
Problem
Existing three-phase electric motors face limitations in miniaturization due to constraints on winding dimensions and copper volume, leading to degraded performance when trying to reduce their size while maintaining power levels.
Innovation Solution
A stator design with three consecutive wound teeth and one to three non-wound teeth, where the angular width, length, and shape of the non-wound teeth are adjusted to optimize current-free torque and magnetic forces, allowing for a more compact and efficient motor structure with reduced winding volume and increased copper allocation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Volume of moving object
If the motor dimensions are reduced homothetically to achieve miniaturization, then the motor size and mass are decreased, but the volume available for conductive wires is proportionally reduced leading to degraded performance
Solution Approach 1:
The stator teeth are segmented into two distinct groups: wound teeth carrying electrical windings and non-wound teeth without windings. This segmentation allows the motor to have fewer total teeth (reducing volume) while maintaining sufficient copper volume in the wound teeth for acceptable performance. The non-wound teeth serve structural and magnetic functions without requiring winding space.
Solution Approach 2:
Different regions of the stator have different properties: wound teeth are optimized for electromagnetic actuation with embedded windings, while non-wound teeth are optimized for structural support and magnetic circuit completion without windings. This local differentiation allows each region to be optimized for its specific function, enabling miniaturization without performance loss.
2Reliability
If the winding volume is increased to maintain performance at smaller sizes, then the motor performance is maintained, but the motor bulk cannot be reduced below a certain limit
Solution Approach 1:
Not all stator teeth need to be wound with copper to achieve acceptable performance. By winding only the necessary number of teeth (three consecutive wound teeth) and leaving others non-wound, the design uses partial action - sufficient electromagnetic actuation is achieved with reduced total copper volume, enabling smaller motor size while maintaining performance.
3Quantity of substance
If the number of stator teeth is reduced to allow more copper volume per tooth, then the copper allocation is improved, but the stator structure becomes less symmetric
Solution Approach 1:
The stator intentionally uses an asymmetric number of teeth (5 or 7 teeth instead of the conventional 6 or more) with an asymmetric distribution pattern (three consecutive wound teeth followed by two or three non-wound teeth). This asymmetric configuration allows increased copper volume in the wound teeth while maintaining functional performance through the specific arrangement of wound and non-wound teeth.
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 enhances the motor's performance by minimizing current-free torque ripple, balancing magnetic forces, and allowing for more compact integration with reduction gears, while maintaining robustness and ease of mass production.
Implementation Method 1
a three-phase electric motor, formed by a stator part excited by three electric windings and a magnetized rotor
Implementation Method 2
a magnetized rotor, the stator part having radially extending teeth
Data Source
AI summary
A three-phase electric motor, formed by a stator part excited by three electric windings and a rotor comprising a plurality of magnetized poles, the stator part having radially extending teeth, the stator part comprising: three consecutive wound teeth, each carrying a winding, in a first angular sector, and one to three non-wound complementary teeth, in a second angular sector complementary to the first angular sector.