Alternator Rotor with Non-Magnetic Spacer and Segmented Cores
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Solution Overview
Problem
Conventional alternators face challenges in increasing electric power generation per unit weight due to high magnetic reluctance and weight increase from thicker rotor cores and permanent magnets, which also complicates magnetic flux distribution and stability.
Innovation Solution
A rotor design featuring laminated core layer units with a cylindrical field coil and alternating claw-shaped magnetic poles, where the magnetic flux directly and indirectly extends through an outer magnetic body, reducing magnetic reluctance and weight by optimizing the ratio of outer circumferential to rotational diameters, and using a non-magnetic spacer to stabilize the structure.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Power
If the thickness of rotor cores is increased to reduce magnetic reluctance, then magnetic flux density is improved, but the weight of the alternator increases
Solution Approach 1:
The rotor core is divided into multiple thin laminated sheets stacked together, creating a segmented structure that reduces eddy current losses while maintaining magnetic flux density. This segmentation allows the core to achieve high magnetic performance without excessive weight gain from thickening.
Solution Approach 2:
The rotor core uses composite construction combining magnetic steel laminations with non-magnetic supporting structures and spacing elements. This composite approach optimizes the magnetic path while controlling overall weight, allowing high flux density in critical areas without uniformly thickening the entire rotor core.
2Power
If permanent magnets are added to increase electric power generation, then power output is improved, but the device complexity and weight increase
Solution Approach 1:
The patent extracts the permanent magnet component from the rotor structure, using only electromagnetic induction from field coils. This eliminates the complexity of magnet embedding, securing, and thermal management while maintaining power generation capability through optimized coil and core design.
Solution Approach 2:
The patent replaces the mechanical/physical permanent magnet system with an electromagnetic field coil system. This substitution simplifies the rotor structure by eliminating magnet mounting complexities while allowing flexible magnetic field control through electrical excitation.
3Power
If the ratio of outer circumferential diameter to rotational diameter is optimized, then electric power per unit weight is improved, but manufacturing precision requirements increase
Solution Approach 1:
The patent optimizes the diameter ratio parameter within a specific range (0.54-0.60) to achieve maximum power-to-weight ratio. This parameter optimization balances electromagnetic performance with manufacturing feasibility, avoiding extreme ratios that would require excessive precision while maintaining high efficiency.
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 enhances magnetic flux density, reduces the number of coil turns, and lightens the alternator weight, resulting in increased electric power generation per unit weight while maintaining stability and reducing noise and deformation risks.
Implementation Method 1
When a field current is supplied to the coil 105 of the rotor 100 through the slip rings 106, a magnetic flux is generated by the coil 105 and passes through the cores 110 and 111 and a core of the stator
Implementation Method 2
When the rotor 100 is rotated, electric power is electromagnetically generated in the alternator
Data Source
AI summary
A rotor of alternator has core layer units serially located along axial direction. Each unit has a field coil generating magnetic flux and two rotor cores receiving the flux on respective sides of the coil in axial direction. Each core has a first yoke portion located on inner side of the coil, a second yoke portion extending from the first yoke portion toward the outer side and magnetic poles extending from the second yoke portion in the axial direction. The poles of one core and the poles of the other core in each unit extend toward different axial sides and are alternately arranged in circumferential direction on the outer side of the coil. A ratio of the outer circumferential diameter of the first yoke portions to the rotational diameter of the poles is lower than 0.54.