Continuous Stator Winding for Electric Motor Stray Field Reduction
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Solution Overview
Problem
Existing stator designs for electronically commutated electric motors are complex and costly due to extensive wiring and high stray field losses, which complicates the connection of wires and sensor placement in power steering systems.
Innovation Solution
A cylindrical stator with ferromagnetic poles wound continuously around the stator casing, featuring three pole groups with alternating winding directions, where windings are brought out at the beginning and end of each group for efficient connection and minimized cuts, reducing stray fields and simplifying sensor placement.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Power
If wires are connected outside the stator to form multi-phase windings, then the motor can achieve high drive power, but the production cost increases and stray fields are generated
Solution Approach 1:
The patent merges the winding process and connection process into a single continuous operation. The single wire winds around multiple poles in sequence and forms all necessary connections during the winding process itself, eliminating the need for separate connection steps outside the stator. This combines multiple operations into one, reducing production complexity while maintaining the multi-phase winding configuration needed for high drive power.
Solution Approach 2:
The patent performs all connection actions preliminarily during the winding process. The wire is pre-routed and pre-connected to form the complete multi-phase winding arrangement before the winding process ends. This preliminary action eliminates the need for subsequent connection operations outside the stator, reducing both production time and complexity.
2Ease of manufacture
If wires are led out and back via loops on the front side of the stator, then winding is simplified, but the number of connection points increases and stray fields are distributed over the circumference
Solution Approach 1:
The patent extracts the connection points from the peripheral distribution and concentrates them at specific locations during the winding process. Instead of creating loops distributed over the entire front side circumference, the wire is routed to concentrate connections at predetermined locations, removing the harmful distributed stray fields while maintaining manufacturing simplicity.
Solution Approach 2:
The patent applies local quality by concentrating the connection activity at specific localized areas during winding rather than distributing it uniformly across the front side. The wire routing is designed to create connections at specific poles or pole groups, creating localized connection zones rather than distributed peripheral connections, thereby reducing stray fields in critical sensor areas.
3Adaptability or versatility
If connection points are distributed over the entire peripheral area, then wiring flexibility is improved, but sensor placement becomes difficult and stray field losses increase
Solution Approach 1:
The patent segments the winding process into distinct phases corresponding to different pole groups, with each phase being completed sequentially. This segmentation allows the wire to be routed and connected in an organized manner at specific locations for each phase, maintaining wiring flexibility through systematic routing while concentrating connections in controlled areas that preserve sensor placement areas free from stray fields.
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 results in a compact, high-efficiency motor with reduced production costs and improved sensor resolution, allowing for more precise control and operation of electric motors in power steering systems.
Implementation Method 1
The multi-phase stator windings disclosed there are wound onto the stator poles one after the other per phase and its wires are connected to one another to form a three-phase system outside the stator after each phase arrangement has been wound
Data Source
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AI summary
The invention relates to a stator for an electric motor comprising several poles (P) that are directed inwards towards the motor axis (2) and that surround a rotor (1), each pole (P) being provided with one winding (L) and the coils of the windings (L) being wound around the poles (P) one after the other without interruption. The stator (20) contains at least three pole groups (n), having at least three poles (P) and each group having the same number of poles (P). The windings (L) run out from the end face at least at the respective beginning and end of a pole group and are contacted there in such a way that the windings (L) associated with each pole group contain their own connection pair (U-U', V-V', W-W') and one connection (U', V', W') of each of these connection pairs is connected to a star point (Y) on the end face of the stator (20). The windings (L) are wound around the poles (P) one after the other with an alternating winding direction (WR), a single pole (P) having a winding (L) with the same winding direction as the preceding winding (L) of the preceding pole group (n) at an individual transition point between two pole groups (n).