Galvanic Separators for Cascaded Voltage Stator Modularization

Solution Overview

Problem

High voltage electric machines in aircraft face partial discharge issues at high altitudes due to the weight and complexity of additional insulation required, which increases the weight and complexity of aviation electric machines.

Innovation Solution

The electric machine features a modularized stator with galvanic isolation between modules and the housing, allowing each module to operate at independent voltages, reducing the voltage stress and enabling lighter insulation and more efficient cooling.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If additional insulation is added to prevent partial discharge at high altitudes, then reliability is improved, but weight increases

Engineering Contradiction:

Improvepartial discharge preventionVSAvoidinsulation weight

Core Design Contradiction:

ReliabilityVSWeight of moving object

Solution Approach 1:

The stator is divided into multiple independent voltage modules (first voltage module, second voltage module, etc.) with each module operating at a different voltage level. Galvanic separators are inserted between adjacent modules to provide electrical isolation. This segmentation allows each module to have optimized insulation levels appropriate to its voltage, reducing the overall insulation weight compared to a single high-voltage stator while maintaining partial discharge prevention through proper voltage grading.

Inventive Principle:

Principle #1Segmentation

2Reliability

If additional insulation is added to prevent partial discharge at high altitudes, then reliability is improved, but device complexity increases

Engineering Contradiction:

Improvepartial discharge preventionVSAvoidinsulation complexity

Core Design Contradiction:

ReliabilityVSDevice complexity

Solution Approach 1:

The stator is divided into multiple independent voltage modules (first voltage module, second voltage module, etc.) with each module operating at a different voltage level. Galvanic separators are inserted between adjacent modules to provide electrical isolation. This segmentation allows each module to have optimized insulation levels appropriate to its voltage, reducing the overall insulation weight compared to a single high-voltage stator while maintaining partial discharge prevention through proper voltage grading.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The galvanic separators are pre-positioned between the voltage modules during assembly, establishing the voltage grading structure before the machine operates. This preliminary arrangement of insulation and electrical isolation structures ensures that partial discharge prevention is built into the design from the outset, rather than requiring complex additional insulation layers to be added later.

Inventive Principle:

Principle #10Preliminary action

3Weight of moving object

If high voltage cables are used to reduce transmission cable weight, then weight is reduced, but partial discharge issues occur at high altitudes

Engineering Contradiction:

Improvetransmission cable weightVSAvoidpartial discharge resistance

Core Design Contradiction:

Weight of moving objectVSReliability

Solution Approach 1:

The stator is divided into multiple independent voltage modules (first voltage module, second voltage module, etc.) with each module operating at a different voltage level. Galvanic separators are inserted between adjacent modules to provide electrical isolation. This segmentation allows each module to have optimized insulation levels appropriate to its voltage, reducing the overall insulation weight compared to a single high-voltage stator while maintaining partial discharge prevention through proper voltage grading.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The invention changes the voltage parameter distribution within the stator by using multiple modules at different voltage levels rather than a single high-voltage module. This parameter change (voltage grading) allows the use of lighter insulation materials and reduces the insulation thickness required, thereby reducing weight while maintaining partial discharge resistance through the stepped voltage architecture.

Inventive Principle:

Principle #35Parameter changes

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 reduces partial discharge risks, decreases the weight of insulation, and allows for more effective cooling, enhancing the performance and efficiency of high voltage electric machines in aircraft at high altitudes.

Implementation Method 1

a housing separator galvanically isolating the housing from the stator modules and intermodular separators galvanically isolating the stator modules from one another

Methodology Applied

Scientific EffectGalvanic isolation: Electrical Resistance

Data Source

PatentUS11710991B2High voltage electric machine equipped with galvanic separators for cascaded voltage stator modularization

Publication Date: 2023.07.25 GENERAL ELECTRIC CO

AI summary

A high voltage electric machine and power distribution system including one or more of such electric machines are provided. In one aspect, a high voltage electric machine includes a stator, a rotor, and a housing encasing at least a portion of the stator and rotor. The stator is modularized into cascaded voltage stator modules. The stator modules are galvanically isolated from one another by intermodular separators. At least one intermodular separator is positioned between each adjacent pair of stator modules. The stator modules are also galvanically isolated from the housing by a housing separator. The housing separator is positioned between the stator modules and the housing. Each stator module has an associated set of windings that are wound only within their associated stator module.