Fault-Tolerant Permanent Magnet Machine Phase Isolation
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Solution Overview
Problem
Permanent Magnet (PM) rotating electric machines face challenges in fault tolerance, as shorted windings induce unmanageable currents due to persistent magnetic fields, leading to potential damage and safety hazards, with existing solutions often rendering the machine inoperable or requiring costly downtime.
Innovation Solution
The implementation of a fault-tolerant system that isolates compromised coils by reconfiguring windings into series, hairpin bifilar, or parallel configurations, allowing continued operation by reducing inductive effects and managing coils as independent elements, with additional feedback and control mechanisms for smooth transitions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the machine is rendered safe by stopping excitation currents or physically disconnecting the rotor, then safety hazards are eliminated, but the machine becomes inoperable and loses its primary function
Solution Approach 1:
The patent divides the stator windings into multiple independent phases (e.g., three phases with phases a and b, or five phases with phases a, b, c, and neutral). When a short circuit occurs in one phase, only that specific phase is isolated while other phases continue to operate. This segmentation allows the machine to maintain partial functionality rather than complete shutdown, resolving the contradiction between safety and operational continuity.
Solution Approach 2:
The patent introduces control circuitry and switching devices (such as IGBTs or MOSFETs) as intermediaries between the power source and the stator windings. These intermediaries can rapidly detect short circuit conditions and selectively disconnect only the affected phase while maintaining connection to healthy phases, enabling continuous operation at reduced capacity rather than complete shutdown.
2Reliability
If the rotor is stopped mechanically to prevent damage from shorted windings, then further damage is prevented, but significant time passes causing serious damage before the machine can stop
Solution Approach 1:
The patent replaces mechanical stopping mechanisms with electrical protection systems. Instead of mechanically stopping the rotor through physical disconnection, the system uses electronic control circuitry to detect short circuits and electrically isolate the affected phase through switching devices. This substitution provides rapid response (microseconds to milliseconds) compared to mechanical stopping, preventing damage while maintaining rotor rotation and operational continuity.
3Reliability
If specialized winding schemes and shunts are used to counter induction effects, then current management is improved, but the machine is still rendered inoperable
Solution Approach 1:
The patent implements segmentation by dividing stator windings into multiple independent phases with individual control for each phase. When a short circuit occurs, the control system isolates only the affected phase while maintaining operation of other phases. This selective isolation preserves operational capability unlike previous approaches that disabled the entire machine, while still achieving effective current management in the healthy phases.
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
Enables the PM rotating electric machine to operate with diminished capacity rather than becoming inoperable, reducing downtime and safety risks while maintaining mechanical and electrical balance, and allowing for continued functionality even under faulted conditions.
Implementation Method 1
permanent magnets continue to create a changing flux through the coils of the machine, the machine will continue to induce currents that tend to oppose the change in flux created by the rotating magnetic fields
Implementation Method 2
reconfiguring windings into series, hairpin bifilar, or parallel configurations, allowing continued operation by reducing inductive effects
Data Source
AI summary
The disclosed technology provides systems and methods to employ fault tolerance for rotating electric machines operating as motors or generators. A unique system architecture and control elements allow rotating electric machines the ability to isolate faulted conditions and continue to operate.