Stator End Winding PCB for Compact Electric Machines

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Solution Overview

Problem

The existing stators for electrical rotating machines, particularly in high-power applications like ship propulsion, face inefficiencies due to significant axial space requirements for end windings, leading to increased ohmic losses, complex cooling needs, and mechanical challenges such as vibrations and deformations, which complicate the design and operation of large machines.

Innovation Solution

The stator design incorporates end winding plates integrated with an insulating base body containing high thermal conductivity materials, where conductor tracks are connected to coil bars, reducing axial length and enhancing electrical and mechanical properties by minimizing connection points and optimizing cooling through integrated conductor tracks and cooling channels.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of manufacture

If traditional preformed coils with end windings are used, then the electrical rotating machine can be assembled, but the axial space requirement increases significantly

Engineering Contradiction:
Improvecoil assemblyVSAvoidaxial length
Core Design Contradiction:
Ease of manufactureVSLength of moving object

Solution Approach 1:

The end winding section is transformed from a three-dimensional bent conductor structure into a two-dimensional printed circuit board layout. The conductor tracks are arranged planarly on the PCB, eliminating the need for axial space that would otherwise be required for bent end windings. This dimensional transformation allows the same electrical connectivity to be achieved with significantly reduced axial length.

Inventive Principle:
Principle #17Another dimension (Dimensionality change)

Solution Approach 2:

The mechanical bending and cranking of conductors to form end windings is replaced by electronic circuit trace routing on a PCB. Instead of physically bending copper conductors in three-dimensional space, the electrical connections are established through printed conductor tracks on the circuit board, substituting a mechanical forming process with an electronic manufacturing process.

Inventive Principle:
Principle #28Mechanics substitution (Replace mechanical system)

2Reliability

If traditional end windings with long conductor lengths are used, then electrical connections can be made, but ohmic losses increase

Engineering Contradiction:
Improveelectrical connectionVSAvoidohmic losses
Core Design Contradiction:
ReliabilityVSLoss of energy

Solution Approach 1:

The conductor path is redistributed from a long three-dimensional bent structure into a compact two-dimensional planar layout on the PCB. This dimensional change allows the electrical current to travel through optimized conductor tracks that minimize resistance while maintaining all necessary electrical connections, thereby reducing ohmic losses.

Inventive Principle:
Principle #17Another dimension (Dimensionality change)

3Reliability

If traditional end windings are used, then coils can be connected, but cooling requirements and insulation space increase

Engineering Contradiction:
Improvecoil connectionVSAvoidcooling and insulation structure
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The end winding section is merged with the stator core assembly by integrating the PCB directly onto the stator core. This consolidation eliminates the need for separate cooling structures and insulation components that would be required for traditional end windings, as the PCB itself serves as both the electrical connection medium and the structural element that requires cooling and insulation.

Inventive Principle:
Principle #5Merging (Combining)

Solution Approach 2:

The PCB serves multiple functions simultaneously: it provides electrical connections between coils, acts as a structural support element, requires cooling for thermal management, and needs insulation from the stator core. By designing the PCB to fulfill all these roles, the number of separate components and the overall system complexity are reduced.

Inventive Principle:
Principle #6Universality (Multi-functionality)

4Reliability

If high-speed low-pole machines are designed with traditional end windings, then electrical connections are achieved, but rotor dynamics are adversely affected

Engineering Contradiction:
Improveelectrical connectionVSAvoidrotor speed
Core Design Contradiction:
ReliabilityVSSpeed

Solution Approach 1:

The electrical connection structure is moved from a three-dimensional end winding configuration that extends axially into a two-dimensional PCB layout. This dimensional transformation reduces the axial length and bearing spacing, allowing high-speed rotation without the adverse rotor dynamic effects caused by long overhanging conductors.

Inventive Principle:
Principle #17Another dimension (Dimensionality change)

5Stability of the object's composition

If stiffening measures are added to traditional end windings, then vibrations are prevented, but device complexity and weight increase

Engineering Contradiction:
Improvevibration resistanceVSAvoidstiffening structure
Core Design Contradiction:
Stability of the object's compositionVSDevice complexity

Solution Approach 1:

The mechanical stiffening measures required for traditional end windings are replaced by the inherent structural rigidity of the PCB. The rigid circuit board provides sufficient mechanical support and vibration resistance without requiring additional stiffening components, thereby reducing device complexity and weight while maintaining stability.

Inventive Principle:
Principle #28Mechanics substitution (Replace mechanical system)

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 reduces axial length, minimizes electrical losses, and improves mechanical stability by integrating thermally conductive materials and efficient cooling, resulting in improved efficiency and reduced weight for high-power electrical rotating machines.

Implementation Method 1

end winding plates (32) integrated with an insulating base body (38) containing high thermal conductivity materials

Methodology Applied
Scientific EffectThermal conduction: Conduction (thermal)

Data Source

PatentEP3652839B1Rotor for an electric rotating machine
Publication Date: 2023.03.08 SIEMENS AG
  • EP3652839B1 patent drawingFigure 1
  • EP3652839B1 patent drawingFigure 2
  • EP3652839B1 patent drawingFigure 3

AI summary

The invention relates to a stator (8) for an electrical rotating machine (2), in particular for use in a pod drive (56), which stator has a laminated stator core (20) having coils (22). In order to achieve improved electrical and mechanical properties in comparison with the prior art while also achieving a small axial length, according to the invention, the coils (22) each have at least one groove portion (26), at least one winding overhang portion (28) and at least one connecting portion (30), the winding overhang portion (28) being designed as a stator winding overhang board (32), which is arranged at an end face of the laminated stator core (20) and has conducting tracks (36) integrated into an insulating main body (38), a conductor (34) of the groove portion (26) and a conducting track (36) of the winding overhang portion (28) being connected in a connecting portion (30), the conductors (34) of the groove portion (26) each having a first number (n1) of partial conductors (40) electrically insulated from each other and/or the conducting tracks (36) of the winding overhang portion (28) each having a second number (n2) of partial conducting tracks (50) electrically insulated from each other, and the partial conductors (40) of the groove portion (26) electrically insulated from each other and/or the partial conducting tracks (50) of the winding overhang portion (28) electrically insulated from each other being electrically conductively connected in the connecting portion (30).