Electric Machine Pole Grouping for Flux Control
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Solution Overview
Problem
Conventional electric machines with permanent magnets and electromagnetic poles suffer from significant power losses and heat generation due to long-range magnetic flux, which complicates cooling and manufacturing processes.
Innovation Solution
The electric machine design features electromagnetic pole groups with adjacent poles spaced closer within groups and farther between groups, creating short-range magnetic flux loops, reducing losses and allowing for efficient cooling and simplified manufacturing by utilizing the space between groups for air flow or cooling devices.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of energy
If electromagnetic poles are uniformly distributed on the stator, then the machine structure is simple and manufacturing is easy, but long-range magnetic flux occurs causing high power losses and heat generation
Solution Approach 1:
The stator electromagnetic poles are segmented into multiple pole groups, where each group contains poles with the same polarity. This segmentation creates distinct magnetic circuit regions that confine magnetic flux to shorter paths within each pole group, preventing long-range flux traversal across the entire rotor circumference and thereby reducing power losses in the permanent magnets.
Solution Approach 2:
Different regions of the stator are assigned different magnetic pole configurations - specifically, poles are arranged in groups with alternating polarity patterns. This local differentiation creates short-range magnetic circuits in specific zones while maintaining overall machine functionality, addressing the power loss problem locally without requiring complete redesign of the entire machine structure.
2Temperature
If electromagnetic poles are uniformly distributed on the stator, then manufacturing is simple, but comprehensive cooling requirements are needed due to heat generation
Solution Approach 1:
The pole group arrangement that creates non-uniform magnetic flux distribution also creates localized heat generation patterns. By strategically positioning cooling channels to align with high-density pole groups, the design converts the harmful heat concentration into a benefit - enabling more efficient heat removal in critical zones without requiring comprehensive cooling of the entire machine, thus simplifying the overall cooling system.
3Loss of energy
If electromagnetic poles are grouped with even number of poles per group, then long-range magnetic flux is reduced, but the pole spacing arrangement becomes more complex
Solution Approach 1:
The pole groups are arranged with asymmetric spacing patterns - poles within a group have specific spacing optimized for short-range flux, while spacing between groups follows a different pattern. This asymmetric arrangement accepts slightly more complex manufacturing precision requirements in exchange for dramatically reduced long-range magnetic flux losses, as the asymmetric configuration effectively breaks the symmetry that would otherwise allow flux to traverse the entire rotor.
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 design significantly reduces power losses and heat generation, enhances cooling efficiency, and simplifies the assembly and manufacturing of electric machine components while maintaining performance comparable to uniformly distributed stator electromagnetic poles.
Implementation Method 1
adjacent electromagnetic poles of an electromagnetic pole group are linked to each other so as to generate magnetic fields of opposite direction in operation
Implementation Method 2
Electric machine (10) comprises a rotor (200) equipped with permanent magnets (204, 206, 208, 210) and a stator (100) equipped with electromagnetic poles
Data Source
Figure 1
Figure 2
AI summary
An electric machine comprises a rotor (200) equipped with permanent magnets (204, 206, 208, 210), and a stator (100) equipped with electromagnetic poles. The electric machine is characterized in that several adjacent electromagnetic poles respectively constitute an electromagnetic pole group in which the adjacent electromagnetic poles are spaced apart at a first electromagnetic pole spacing, that adjacent electromagnetic poles belonging to different electromagnetic pole groups are spaced apart at an electromagnetic pole spacing greater than said first electromagnetic pole spacing, that each electromagnetic pole group has an even number of electromagnetic poles, and that adjacent electromagnetic poles of an electromagnetic pole group are linked to each other so as to generate magnetic fields of opposite direction in operation.