Brushless Machine Stator with Cascaded End Loops
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Solution Overview
Problem
Conventional brushless electric machines lack sufficient magnetic circuitry for high power density and require expensive drive end bearings and external cooling, leading to larger package sizes and inefficiencies in powering vehicle electrical systems.
Innovation Solution
The design incorporates a brushless alternator with a housing, stationary field coil, shaft, bearing, and stator with a cylindrically-shaped core having circumferentially spaced core slots and a winding with end loop segments and straight segments, optimizing magnetic flux and reducing air gap reluctance to achieve higher power density in a compact form.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Power
If conventional brushless electric machine components are used, then the structure is simple and easy to manufacture, but the magnetic circuit is insufficient to achieve higher power densities
Solution Approach 1:
The magnetic circuit is divided into multiple segments including a yoke, multiple poles with pole shoes, and multiple core slots. This segmentation allows for optimized magnetic flux paths in each region, enabling higher power density while maintaining manufacturability through modular construction.
Solution Approach 2:
The invention transitions from a conventional two-dimensional winding arrangement to a three-dimensional configuration with core slots extending axially and radially. The stator core includes a yoke and multiple poles arranged in three-dimensional space, allowing magnetic flux to travel through optimized paths that increase power density without proportionally increasing overall size.
2Reliability
If conventional drive end bearings are used, then the support system is simple, but expensive bearings are required
Solution Approach 1:
The stator core structure itself provides support functionality through its yoke and pole assembly that can accommodate bearings in a self-supporting manner. The integrated design allows the magnetic circuit components to serve dual purposes of magnetic flux conduction and mechanical support, reducing dependency on expensive specialized bearings.
3Temperature
If external cooling systems are used, then cooling capability is provided, but the package size increases
Solution Approach 1:
The cooling system is merged with the stator core structure itself. Core slots and the yoke-pole assembly are designed to incorporate cooling channels and pathways that utilize the existing magnetic circuit structure, eliminating the need for separate external cooling components and reducing overall package size.
Solution Approach 2:
The stator core components (yoke, poles, core slots) serve multiple functions simultaneously: conducting magnetic flux, providing mechanical support, and facilitating cooling. This multi-functionality integrates thermal management into the existing structure without requiring additional space-dedicated cooling systems.
4Power
If conventional stator windings are used, then the winding structure is simple, but the magnetic flux optimization is insufficient for high power density
Solution Approach 1:
Different regions of the stator core are assigned different winding configurations optimized for their specific functions. Core slots are strategically positioned and sized to accommodate windings that optimize magnetic flux density in specific areas, allowing local optimization of power output without requiring complete redesign of the entire winding 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 configuration enhances power output while reducing the overall size and weight of the electric machine, enabling efficient internal cooling and improved high-speed capability, thus addressing the limitations of conventional designs.
Implementation Method 1
A stator winding including a plurality of phases, with each of the phases having at least one conductor having a plurality of substantially straight segments disposed in the core slots
Implementation Method 2
optimizing magnetic flux and reducing air gap reluctance to achieve higher power density in a compact form
Data Source
AI summary
Disclosed herein is a brushless electric machine comprising, a housing, a stationary field coil, a shaft, a bearing, a pole segment, and a stator. The stator including a core having a plurality of core slots that extend between a first and a second end of the stator core. The stator also including a winding with a plurality of phases, each of the phases having at least one conductor having a plurality of substantially straight segments disposed in the core slots. The straight segments are alternately connected at the first and the second ends of the stator core by a plurality of end loop segments. A section of at least one of the conductors including three consecutive end loop segments and two straight segments, is formed from a single continuous conductor, and one of the core slots houses a plurality of the straight segments arranged in at least one radial row.