Stator Stress Control Scaffold and Dielectric Backfill
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Solution Overview
Problem
Conventional stress control techniques for high voltage electrical machines, such as tapes, face challenges in accurately controlling electrical field concentrations and are prone to air pockets that can lead to corona discharge, degrading insulation and reducing the machines' operational lifetime.
Innovation Solution
An electrical machine with a stator assembly featuring an additively manufactured printed scaffold that includes pores, filled with a dielectric backfill material, providing a stress control structure that surrounds the insulation layer to control electrical field concentrations and prevent corona discharge, utilizing a stress control material different from the dielectric backfill material.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional stress control tapes are used, then stress control function is provided, but air pockets are created between adjacent layers leading to corona discharge
Solution Approach 1:
The patent employs a porous stress control structure that is infiltrated with dielectric fluid. The porous material provides a pathway for complete filling without air pockets, while the dielectric fluid saturates the pores to eliminate voids that would cause corona discharge. This combination maintains stress control functionality while preventing the harmful effects of air pockets.
Solution Approach 2:
The dielectric fluid infiltrating the porous stress control structure creates an inert dielectric environment that replaces air (which causes corona discharge) with a material that suppresses electrical breakdown. The fluid-filled pores provide a stable, non-corona-prone environment around the conductor.
2Manufacturing precision
If conventional taping processes are used, then stress control structure is formed, but accurate control of geometrical structure and electrical properties is difficult
Solution Approach 1:
The stress control structure is divided into two functional components: a porous scaffold providing geometric precision and structural integrity, and a dielectric fluid providing electrical properties. This segmentation allows each component to be optimized independently - the scaffold for geometric control and the fluid for electrical performance.
Solution Approach 2:
The patent creates a composite stress control structure combining porous material and dielectric fluid. The porous scaffold provides precise geometric control and mechanical strength, while the dielectric fluid contributes electrical properties. This composite approach enables accurate control of both geometrical structure and electrical properties that cannot be achieved with conventional homogeneous tapes.
3Reliability
If stress control structure is added to control electrical field, then insulation degradation is reduced, but device complexity increases
Solution Approach 1:
The porous stress control structure provides a three-dimensional network that efficiently controls the electrical field throughout the insulation region. The porous architecture allows dielectric fluid to penetrate and distribute electrical stress control throughout the entire volume, providing comprehensive protection without requiring multiple separate components.
Solution Approach 2:
The composite of porous material and dielectric fluid creates a unified stress control structure that combines mechanical support with electrical field control. This integrated composite approach reduces overall device complexity compared to using multiple separate stress control layers or components.
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
The solution effectively reduces insulation degradation, allows operation at higher voltages and altitudes, and provides better electrical stress grading performance by precisely controlling the electrical properties and geometry of the stress control structure, extending the machine's lifetime and optimizing design.
Implementation Method 1
The stress control structure and the insulation layer are defined by a printed scaffold and a dielectric backfill material... providing a stress control structure that surrounds the insulation layer to control electrical field concentrations
Implementation Method 2
the dielectric backfill material fills the pores... The dielectric backfill material is different from the stress control material
Implementation Method 3
The stress control section of the printed scaffold... provides better electrical stress grading performance by precisely controlling the electrical properties and geometry of the stress control structure
Data Source
AI summary
An electrical machine includes a stator assembly having an annular core and a conductive winding. The annular core includes a central bore. The conductive winding includes one or more stator winding bars disposed circumferentially around the central bore. The one or more stator winding bars include a core conductor and an insulation layer surrounding the core conductor. An end segment of the one or more stator winding bars at a connection interface includes a stress control structure surrounding the insulation layer. The stress control structure includes a printed scaffold and a dielectric backfill material. The dielectric backfill material fills pores of the printed scaffold. The porous scaffold is composed of a stress control material that is different from the dielectric backfill material.