Polygon Stator Core for High Power Density Electric Motors
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Solution Overview
Problem
Conventional brushless direct current (BLDC) motors with round stator cores face limitations in increasing output power due to the lack of space for expanding winding slots, making it difficult to achieve higher performance and smaller size.
Innovation Solution
The use of a polygon stator core with interconnecting yoke portions and varying winding slots of different shapes but similar areas, allowing for increased size and area utilization within the motor, thereby enhancing output power.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Power
If a conventional round stator core is used, then the stator is easy to fabricate, but the output power cannot be increased due to lack of space for winding slots
Solution Approach 1:
The patent applies asymmetry by transitioning from a conventional round stator core to a polygonal stator core with unequal side lengths. The first and second different lengths of sides create asymmetric winding slot areas, allowing optimization of space utilization. This asymmetric design enables increasing the stator core area within the same motor envelope, thereby increasing output power without proportionally increasing the motor's external dimensions.
2Power
If the stator core size is increased to increase output power, then the area utilization rate improves, but the motor size increases
Solution Approach 1:
The patent employs dimensionality change by altering the geometric configuration of the stator core from a circular to a polygonal shape with varying side lengths. This dimensional reconfiguration allows the stator core to occupy more area within the same radial space, effectively increasing the winding slot capacity and output power without increasing the motor's external radius or overall volume.
3Power
If winding slots are made larger to increase output power, then the area utilization rate improves, but the manufacturing complexity increases
Solution Approach 1:
The patent applies local quality by creating winding slots with different areas at different locations around the stator core. The first and second different lengths of sides produce winding slots with locally optimized areas, allowing each slot to be tailored for maximum space utilization. This local differentiation increases the overall area utilization rate and output power while maintaining manufacturability through straightforward polygonal geometry.
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 increases the size of the stator core in limited space, leading to improved area utilization and increased output power, as demonstrated by a 40% power increase in specific motor embodiments.
Implementation Method 1
An electric current flowing through the winding generates a magnetic field. An electromagnetic force is generated by the energized conductor cutting magnetic flux lines, which causes the rotor to rotate with respect to the stator, whereby the electrical energy is converted into kinetic energy.
Data Source
AI summary
An electric motor has a polygon stator core. The polygon stator core includes yoke portions and teeth extending inwardly from the yoke portions. A winding slot is formed between adjacent teeth. Adjacent yoke portions are interconnected by a connecting portion. The winding slots include first winding slots and second winding slots of different shapes. The ratio of the area of a first winding slot to the area of a second winding slot is greater than or equal to 0.9 but less than or equal to 1.1. By changing the shape of the stator core, the size of the winding slots may be increased without increasing the radial dimension of the motor.