Wound Field Synchronous Machine and PMG Torque Control
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Gas turbine engines face challenges in efficiently managing torque during startup, climb, cruise, loiter, and landing phases, particularly in providing sufficient start-up torque without relying on secondary systems and minimizing stress on rotor shafts during temperature transitions.
Innovation Solution
A system comprising a main machine (MM) and a permanent magnet generator (PMG) with dedicated controllers and a DC bus, where the PMG provides supplemental torque during engine start-up and speed changes, and can operate independently during maintenance, reducing the load on the MM and minimizing thermal stress.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Force
If a traditional gas turbine engine uses secondary systems (bleed air systems and air turbine starters) for startup, then sufficient start-up torque can be provided, but the device complexity and system weight increase
Solution Approach 1:
The patent extracts and eliminates the secondary bleed air system and air turbine starter from the gas turbine engine configuration. By using the electric motor-driven compressor system to provide start-up torque directly, the complex pneumatic systems are removed, simplifying the overall device while maintaining sufficient start-up capability through the main machine and PMG combination
Solution Approach 2:
The electric motor and compressor system is designed to perform multiple functions: it serves as the primary drive during normal operation, provides start-up torque during engine startup, and can operate independently during maintenance. This multi-functionality eliminates the need for dedicated secondary startup systems, reducing device complexity while maintaining start-up torque capability
2Device complexity
If the MM provides all torque during engine startup and operation, then the system structure is simplified, but sufficient torque may not be available during all phases particularly startup and low-speed operations
Solution Approach 1:
The patent segments the torque provision function between two independent systems: the main machine (MM) electric motor-compressor system and the permanent magnet generator (PMG) assist system. The PMG is specifically engaged during startup and low-speed phases when additional torque is needed, while the MM handles normal operation. This segmentation allows each system to be optimized for its specific operational phase, ensuring sufficient torque availability without requiring the MM to be oversized for all conditions
Solution Approach 2:
The system dynamically switches between different torque sources based on operational phase. During startup and low-speed operations, the PMG provides supplemental torque to the MM. During normal operation, the MM operates independently. This dynamic allocation of torque sources ensures sufficient force is available when needed while maintaining simplified system structure
3Temperature
If liquid-cooled controllers are used for the MM and PMG, then better thermal management is achieved, but the device weight and complexity increase
Solution Approach 1:
The controllers utilize the existing gas turbine engine air intake system for cooling, rather than requiring dedicated liquid cooling infrastructure. The ambient air flowing through the engine during normal operation is directed through heat exchangers on the controllers, allowing them to dissipate heat using the engine's own airflow. This self-service approach provides effective thermal management while avoiding the added weight and complexity of separate liquid cooling systems
Solution Approach 2:
The cooling function for the controllers is merged with the engine's existing air intake and airflow system. Instead of creating a separate thermal management subsystem, the design integrates controller cooling into the engine's natural airflow path, using the same air resource for both engine operation and electronic component thermal management, thereby reducing overall system complexity
4Strength
If the PMG operates independently during maintenance, then the MM can be deactivated reducing stress on the rotor shaft, but the system requires additional control complexity
Solution Approach 1:
The control system dynamically reconfigures based on operational mode. During maintenance or low-speed operations, the PMG is dynamically switched to independent operation to drive the rotor shaft without engaging the MM, thereby reducing mechanical stress and thermal loading on the rotor shaft. During normal operation, the system transitions to MM-driven mode. This dynamic operational flexibility protects the rotor shaft during vulnerable phases while maintaining system simplicity through standardized control architecture
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 allows for efficient engine start without secondary power sources, reduces stress on rotor shafts, and optimizes power usage by enabling air-cooled controllers, eliminating the need for bleed air systems and air turbine starters, and supports both wide-body and narrow-body aircraft with tailored power management.
Implementation Method 1
a permanent magnet generator (PMG) with dedicated controllers and a DC bus, where the PMG provides supplemental torque during engine start-up and speed changes
Implementation Method 2
A system comprising a main machine (MM) and a permanent magnet generator (PMG) with dedicated controllers and a DC bus
Implementation Method 3
enabling air-cooled controllers
Implementation Method 4
air-cooled controllers
Data Source
Figure 1
Figure 2~3
AI summary
Disclosed is a system for a gas turbine engine, the gas turbine engine comprising a primary shaft (215), the system including a rotor shaft (210); a plurality of components connected to the rotor shaft, including a wound field synchronous main machine (MM) (220) and a permanent magnet generator (PMG) (230); and wherein the PMG, alone or with the MM provide torque to change rotational speed of the rotor shaft, thereby changing rotational speed of the primary shaft.