Multi-Stack Transposition Coils for Slot Space and Loss Balance
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Solution Overview
Problem
The challenge in electric motor design is to balance core area and conductor size to minimize losses while ensuring mechanical strength and preventing conductor insulation damage, as larger core areas reduce flux density but increase conductor losses, and smaller core areas increase flux density but decrease conductor losses, with constraints on conductor width-to-thickness ratios and manufacturing complexities.
Innovation Solution
The solution involves a transposition coil design with multiple separately-insulated stacks and an outer main wall insulation, where the number of turns can vary among stacks, and specific manufacturing methods like Zig-Zag-Then-Step and Double-series-stack-top-to-bottom-bridge to optimize turn configurations and reduce stress on conductors, allowing for odd or even numbers of turns and multi-stack arrangements.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of energy
If the number of turns is increased to meet flux density requirements, then core flux density is maintained, but the slot space required increases reducing available area for conductors
Solution Approach 1:
Instead of placing all turns in a single stack, the total number of turns is segmented across multiple stacks. This allows the conductor cross-sectional area in each stack to be larger while the total turns are distributed, thereby reducing the height requirement per stack and fitting within the slot dimensions while maintaining the required total flux density.
Solution Approach 2:
The coil design transitions from a single-stack configuration to a multi-stack configuration, utilizing the width dimension of the slot more effectively. By arranging stacks side-by-side rather than stacking them vertically, the design maximizes the use of available slot width while reducing the height requirement, thereby accommodating larger conductor cross-sections.
2Loss of energy
If the conductor width to thickness ratio is increased to reduce conductor losses, then conductor area increases reducing conductor losses, but manufacturing becomes difficult and conductor insulation may be damaged
Solution Approach 1:
The conductor is divided into multiple stacks with different turn counts rather than using a single conductor with excessive width. This segmentation allows each stack to use conductors with moderate width-to-thickness ratios that are easier to manufacture and insulate, while the collective arrangement of multiple stacks achieves the required total conductor area for minimizing 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 approach allows for efficient distribution of turns and insulation, reducing stress and increasing the number of turns that can be accommodated, thereby enhancing the motor's performance and meeting design constraints such as flux density and torque requirements without exceeding frame size limitations.
Implementation Method 1
To create flux density in a core of a motor, a number of turns composed of conductors are wound into the slots of a core
Data Source
AI summary
Transposition coils and insulation for transposition coils. One example provides a transposition coil including a plurality of conductor turns arranged in at least two separate stacks and an outer main wall insulation that encircles the at least two separate stacks. Each of the at least two separate stacks are provided with dedicated main wall insulation that encircles exactly one of the at least two separate stacks.