Transverse Flux Machine Stator Segmentation and Pole Shoe Geometry
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Solution Overview
Problem
Electric machines face challenges in minimizing saturation losses while maintaining high torque and compact design, particularly in transverse flux machines where leakage flux and pole shoe saturation are concerns.
Innovation Solution
The electric machine design features a stacked stator configuration with offset stator strand segments and a bulbous pole shoe shape that deflects field lines, minimizing leakage flux and avoiding saturation, allowing for high torque generation with a compact and efficient structure.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Power
If a compact transverse flux machine design is used, then high torque density is achieved, but pole shoe saturation occurs leading to increased losses
Solution Approach 1:
The stator is divided into multiple sub-stacks, each containing multiple stator strand segments. This segmentation allows the magnetic flux to be distributed across multiple paths, reducing the flux density in individual pole shoes and preventing saturation while maintaining high overall torque output.
Solution Approach 2:
The patent introduces an axial dimension to the flux path by stacking multiple sub-stacks and strand segments. This transforms the traditional planar flux distribution into a three-dimensional flux pattern, creating additional magnetic circuit paths that reduce saturation in any single pole shoe while maintaining compact radial dimensions.
2Loss of energy
If leakage flux is minimized through conventional design, then efficiency improves, but torque generation is reduced
Solution Approach 1:
The patent applies different current orientations to different stator strand segments within the same sub-stack. Adjacent strand segments have opposite current directions, creating localized magnetic fields that reinforce each other while canceling out leakage flux. This local optimization maintains high torque generation while minimizing energy losses.
Solution Approach 2:
The stator combines multiple materials and structures: laminated steel sheets for the core, copper windings for the coils, and insulating materials between layers. This composite structure optimizes magnetic flux guidance while minimizing leakage, achieving both high efficiency and high torque simultaneously.
3Power
If high torque is generated through increased flux density, then power output increases, but saturation losses increase
Solution Approach 1:
By dividing the stator into multiple sub-stacks with multiple strand segments each, the total flux required for high power output is distributed across many smaller flux paths. This maintains lower flux density in individual pole shoes (avoiding saturation) while achieving high overall power output through the cumulative effect of all segments.
Solution Approach 2:
The patent changes the geometric parameters of the magnetic circuit by introducing multiple stacked layers with specific axial offsets. This alters the flux distribution parameters, allowing high power output through increased total active area while maintaining favorable flux density ratios that prevent saturation losses.
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 achieves optimal torque production with minimal leakage flux and reduced saturation, enhancing mechanical stability and noise reduction, while maintaining high efficiency and compactness.
Implementation Method 1
Several alternating magnetic fields are superimposed to form a rotating field, so that a rotational motion is generated in interaction with an excitation field of the rotor
Implementation Method 2
a bulbous pole shoe shape that deflects field lines, minimizing leakage flux and avoiding saturation
Data Source
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AI summary
Disclosed is an electric machine, in particular a transverse flux machine, wherein the stator is composed of a stack of phase segments, each of which includes at least one stator segment and a stator winding, especially a single winding. Each stator segment has an annular stator web, onto which pole shoes are molded. In particular, said pole shoes extend radially inward and/or in the direction of the rotor and/or are arranged between the rotor and the annular stator web. In particular, the pole shoes have similar shapes, the axial width of the pole shoe decreasing as the radial distance increases. The associated shape lies between a first and a second shape, the first shape being a linear function of the radial distance, in particular the pole shoe rear that is part of the first shape being a flat surface, and the second shape being a circular function, in particular a circular sector function, in particular the pole shoe rear that is part of the second shape being a surface of a cylinder sector.