Polyphase Stator Winding with Pointed Connection Heads

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Solution Overview

Problem

Conventional polyphase stators in rotating electrical machines face challenges in optimizing the length of the stator winding to balance cooling efficiency and material usage, as reducing the length of the winding can lead to reduced airflow and increased resistance, while increasing the length can compromise cooling.

Innovation Solution

The stator design features a polyphase stator with notches that accommodate a winding configuration where connection heads and feet have a pointed shape with a rounded apex, optimizing the axial length between 15 and 20 mm, allowing for reduced resistance and improved airflow through the buns for effective cooling.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Loss of energy

If the axial length of the stator winding is reduced, then the resistance is lowered and material usage is optimized, but the airflow through the winding is reduced and cooling efficiency deteriorates

Engineering Contradiction:
ImproveresistanceVSAvoidcooling efficiency
Core Design Contradiction:
Loss of energyVSTemperature

Solution Approach 1:

The invention changes the geometric parameters of the connection heads and feet by giving them a pointed shape with a rounded apex instead of conventional shapes. This parameter change allows the axial length to be reduced to 15-20 mm while maintaining adequate airflow passages, thereby reducing resistance without compromising cooling efficiency

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The invention applies curvature by rounding the apex of the connection heads and feet. This rounded geometry optimizes the airflow path through the winding buns, ensuring that cooling air can effectively pass through the reduced axial length structure while maintaining proper ventilation and heat dissipation

Inventive Principle:
Principle #14Spheroidality (Curvature)

2Temperature

If the axial length of the stator winding is increased, then the airflow and cooling efficiency are improved, but the resistance increases and material usage is excessive

Engineering Contradiction:
Improvecooling efficiencyVSAvoidresistance
Core Design Contradiction:
TemperatureVSLoss of energy

Solution Approach 1:

The invention optimizes the axial length parameter to a specific range of 15-20 mm, avoiding excessive length. The pointed shape with rounded apex of the connection heads and feet is specifically designed to maximize airflow efficiency within this constrained length, achieving effective cooling without the resistance and material waste associated with longer windings

Inventive Principle:
Principle #35Parameter changes

3Productivity

If the axial length of the connection heads and feet is reduced to 15-20 mm, then the resistance is lowered and the machine becomes more compact, but the airflow passage may be compromised

Engineering Contradiction:
Improvemachine efficiencyVSAvoidairflow passage
Core Design Contradiction:
ProductivityVSArea of stationary object

Solution Approach 1:

The rounded apex of the connection heads and feet creates optimized airflow passages within the compact 15-20 mm axial length. This curved geometry prevents flow restriction that would occur with sharp edges or flat surfaces, maintaining adequate air passage area despite the reduced overall dimensions

Inventive Principle:
Principle #14Spheroidality (Curvature)

Solution Approach 2:

The invention applies different geometric qualities to different parts of the connection heads and feet. The pointed shape with rounded apex provides local optimization of airflow paths at critical locations, ensuring that the reduced axial length does not compromise the airflow passage area where it is most needed for cooling

Inventive Principle:
Principle #3Local quality

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 reduces the axial length of the winding, lowering resistance and enhancing airflow, thereby increasing the machine's efficiency and flexibility in power output while maintaining efficient heat exchange.

Implementation Method 1

This circulation of air makes it possible to cool the buns of the winding 12 of the stator 13, as well as the current rectifying device 11 and the voltage regulator

Methodology Applied
Scientific EffectForced Convection: Forced Convection

Implementation Method 2

As is known when the excitation winding 5 of the rotor 4 is electrically energized and the shaft of the rotor rotates, the rotor is magnetized and an induced alternating current is generated in the winding 12 of the stator 13

Methodology Applied
Scientific EffectElectromagnetic Induction: Electromagnetic Induction

Data Source

PatentEP2171830B1Polyphase stator for an internally ventilated rotating electrical machine, and rotating electrical machine comprising such a stator
Publication Date: 2019.05.01 VALEO EQUIP ELECTRIC MOTEUR
  • EP2171830B1 patent drawingFigure 1
  • EP2171830B1 patent drawingFigure 2
  • EP2171830B1 patent drawingFigure 3~4

AI summary

The polyphase stator for an internally ventilated rotating electrical machine comprises a body (14) provided with slots and carrying a coil (12) having at least one winding per phase, which comprises: a plurality of pairs of lateral branches each intended to be mounted in a slot of the body (14); a plurality of connecting heads (50 to 55) extending outside the body (14) so as to form a first lead-out (42) and interconnect each pair of lateral branches; a plurality of coupling feet (150 to 155) offset circumferentially with respect to the plurality of connecting heads and extending outside the body (14) so as to form a second lead-out (43) and interconnect each pair of lateral branches; one of said pluralities having a generally pointed shape and having an axial length of between 15 and 20 mm. The rotating electrical machine comprises such a stator. Application: Stator and alternator or an alternator-starter of a motor vehicle.