Electric Machine Stator With Conductor Bars And End Face Assembly
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Solution Overview
Problem
Conventional electric machines with complex winding patterns and high turn counts are costly and challenging to manufacture, especially for high-speed, low-inductance applications, where increasing the number of turns is expensive and complicates manufacturing.
Innovation Solution
The design features a stator with conductor bars and an end face assembly that electrically connects them, reducing the number of turns and using a controller to regulate excitation current amplitude independently of frequency, allowing for a higher motor voltage and increased motor speed without increasing turn count, and simplifying the winding pattern.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Stress or pressure
If the number of turns in the stator is increased to achieve higher motor voltage, then the motor voltage increases, but the manufacturing cost increases and the manufacturing complexity increases
Solution Approach 1:
The patent changes the fundamental parameter from number of turns to number of slots and magnetic poles. By increasing the number of slots and poles while maintaining a low turn count (1-3 turns), the patent achieves higher motor voltage through the relationship V ∝ (number of slots) × (motor speed) rather than through increased turns, thereby avoiding the manufacturing complexity and cost associated with high turn counts
Solution Approach 2:
The patent divides the stator into multiple slots (e.g., 24 slots) with conductor bars in each slot, and combines them through an end face assembly. This segmentation allows the voltage to be increased by adding more slot segments rather than increasing the complexity within each segment (turns), making the system more manufacturable
2Stress or pressure
If the number of turns in the stator is increased to achieve higher motor voltage, then the motor voltage increases, but the winding pattern complexity increases
Solution Approach 1:
The patent fundamentally changes the approach from varying turns per slot to varying the number of slots and magnetic poles. This parameter change simplifies the winding pattern to 1-3 turns per slot while achieving the desired voltage through increased slot count and pole count, thereby reducing winding pattern complexity
Solution Approach 2:
Instead of the conventional approach of increasing turns to increase voltage, the patent inverts the logic by decreasing turns to 1-3 and compensating by increasing the number of slots and poles. This inversion simplifies the winding pattern while achieving the same voltage increase through a different mechanism
3Adaptability or versatility
If the number of slots and magnetic poles is increased to control voltage-current ratio, then the voltage-current ratio control improves, but the device complexity increases
Solution Approach 1:
The patent uses parameter changes (number of slots, number of poles) to control the voltage-current ratio, which is a fundamental design parameter. While this does increase structural complexity, it provides precise control over the motor's electrical characteristics without requiring complex winding patterns or multiple different stator designs
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 reduces manufacturing costs, increases power density, and achieves higher efficiency by minimizing the number of turns, allowing for a greater number of slots and magnetic poles, which enhances torque density and reduces torque ripple.
Implementation Method 1
A plurality of conductor bars disposed within the slots, wherein an end of each bar protrudes outwardly from the end face; and an end face assembly receiving the ends of all the conductors bars, said end face assembly electrically connecting at least two of the conductor bars
Data Source
AI summary
An electric machine is described together with a stator. The electric machine comprises a stator, said stator comprising a cylindrical stator core having an end face; slots provided on the end face, each slot running through the stator core; a plurality of conductor bars disposed within the slots; and an end face assembly electrically connecting at least two of the conductor bars; a rotor having a plurality of magnetic pole pairs; and a controller electrically connected to said stator for regulating an excitation current supplied to or from the conductor bars, wherein the controller regulates an amplitude of the excitation current independently of a frequency of the excitation current. This arrangement simplifies stator construction and allows for optimisation of the electric machine.