Low-Spool Electric Machine Integration for Gearbox-Free Hybrid Engines
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Solution Overview
Problem
Hybrid engine designs face increased weight and complexity due to additional motor connections, require extra cooling for permanent magnet synchronous motors (PMSM) to prevent demagnetization, and suffer from uncontrolled back EMF voltage issues leading to safety concerns.
Innovation Solution
Integrate the electric machine rotor into the low spool of the turbine engine, eliminating the need for a gearbox and incorporating a squirrel cage induction machine or switched reluctance motor (SRM) that does not require magnets, allowing for safe shutdown and reduced cooling needs.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Power
If a permanent magnet synchronous motor (PMSM) is used in hybrid engine design, then motor functionality is achieved, but weight and complexity of the accessory gear box increase
Solution Approach 1:
The motor rotor is integrated directly into the low spool shaft, merging the motor assembly with the turbine engine's existing rotational component. This eliminates the need for a separate accessory gear box, reducing structural complexity while maintaining motor functionality.
Solution Approach 2:
The low spool shaft serves dual functions: as part of the turbine engine's power transmission system and as the motor rotor. This multi-functionality approach reduces the number of separate components needed, directly addressing the complexity issue.
2Power
If a permanent magnet synchronous motor (PMSM) is used in hybrid engine design, then motor functionality is achieved, but weight of the thermal management system increases due to extra cooling requirements
Solution Approach 1:
The motor is integrated into the existing turbine engine structure, sharing the engine's cooling infrastructure. This eliminates the need for a separate thermal management system, reducing weight while maintaining motor functionality.
3Power
If a permanent magnet synchronous motor (PMSM) is used in hybrid engine design, then motor functionality is achieved, but safety issues arise due to uncontrolled back EMF voltage
Solution Approach 1:
The patent employs a squirrel cage induction motor or switched reluctance motor instead of a PMSM. These alternative motor types do not generate uncontrolled back EMF voltage, eliminating the safety issue while maintaining motor functionality.
4Power
If additional motor connections are added to hybrid engine design, then motor functionality is achieved, but weight increases
Solution Approach 1:
The motor rotor is merged with the low spool shaft, eliminating the need for separate motor mounting structures and connections. This integration reduces the overall weight while maintaining motor functionality.
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 weight and complexity, enhances safety by enabling controlled shutdown, and minimizes cooling requirements, while maintaining efficient operation in harsh environments.
Implementation Method 1
The stator is configured to provide a magnetic field to rotate the rotor
Data Source
AI summary
An electric machine includes a rotor and a stator. The rotor is integrated into a fan drive gear system in an engine. The stator is configured to provide a magnetic field to rotate the rotor.