Fault-Tolerant Four-Phase Electric Drive System
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Solution Overview
Problem
Current fault-tolerant electric drive systems in aerospace, such as those for more electric engines and aircraft, face challenges in reducing power, weight, and installation complexity while maintaining single fault-tolerance, often resulting in overrating and increased complexity.
Innovation Solution
A fault-tolerant four-phase electric drive system with a rotary electric machine featuring a permanent magnet rotor and alternate-wound stator, where phases are evenly spaced and connected to dc buses via contactors, allowing for reconfiguration in case of faults to maintain operation with reduced capacity overrating and complexity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If two individual starter-generator devices are installed per engine to achieve single fault-tolerance, then reliability is improved, but weight and installation volume increase by 100 percent
Solution Approach 1:
The patent combines two starter-generator devices into a single integrated unit with a common housing and shared mechanical components (shaft, mounting pad). This merging reduces the overall installation volume and weight while maintaining the fault-tolerance capability through electrical component duplexing, directly resolving the contradiction between reliability and weight/volume.
Solution Approach 2:
The patent segments the starter-generator system into independent electrical components (two sets of windings, two inverters) within a single mechanical housing. This segmentation allows one electrical subsystem to fail while the other continues to operate, providing fault-tolerance without requiring duplicate mechanical components, thus reducing weight and volume.
2Reliability
If two individual starter-generator devices are installed per engine to achieve single fault-tolerance, then reliability is improved, but device complexity increases
Solution Approach 1:
The patent merges the mechanical components (housing, shaft, mounting interface) into a single shared structure, reducing the number of mechanical parts to be managed and installed. The electrical components remain segmented for fault-tolerance, creating a hybrid architecture that reduces overall complexity compared to fully independent dual systems.
3Weight of stationary object
If four-phase independent drive systems are used to reduce overrating, then weight is reduced, but drive system complexity increases
Solution Approach 1:
The patent implements a universal control architecture that manages four phases through a single controller with standardized drive circuits. Each phase can independently drive different loads (compressor, fan, generator), and the same control hardware handles all phases. This multi-functionality reduces complexity compared to having separate dedicated control systems for each phase.
Solution Approach 2:
The patent employs dynamic phase activation where not all four phases need to operate simultaneously. The controller can activate only the necessary phases based on current operational requirements, reducing the effective complexity and power consumption while maintaining the ability to handle various fault conditions.
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 system achieves reduced weight and complexity while maintaining fault-tolerance, enabling continued operation with limited capacity overrating, thus enhancing the reliability and efficiency of electric drive systems in aerospace applications.
Implementation Method 1
a rotary electric machine having a permanent magnet rotor and an alternate-wound stator
Implementation Method 2
the same machine may be used as a motor to drive a gas turbine engine or as a generator to absorb kinetic energy from a rotating shaft
Data Source
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AI summary
Fault-tolerant four-phase electric drive systems are provided. One such system comprises: a rotary electric machine 112 having a permanent magnet rotor 301 and an alternate-wound stator 302 having eight evenly-spaced coils 303-310 arranged in pairs, each coil in each pair being separated by 180 degrees; a first phase (ΦA) comprising a first one of the coil pairs and a first phase drive circuit 201 connected therewith; a second phase (ΦB) separated by +45 degrees from the first phase and comprising a second one of the coil pairs and a second phase drive circuit 202 connected therewith; a third phase (ΦC) separated by +90 degrees from the first phase and comprising a third one of the coil pairs and a third phase drive circuit 203 connected therewith; a fourth phase (ΦD) separated by +135 degrees from the first phase and comprising a fourth one of the coil pairs and a fourth phase drive circuit 204 connected therewith; and a controller 205 connected with the first, second, third and fourth phase drive circuits 201-204 to control operation thereof.