Fault-Tolerant Actuator Assembly for Safe-Position Failover
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Solution Overview
Problem
Subsea drilling and gas turbine environments pose challenges due to harsh conditions, requiring fault-tolerant actuation systems that can maintain operation despite power and motor controller failures, especially in systems like submersible pumps and fuel control valves.
Innovation Solution
The electric motor assembly includes a primary and secondary power source, motor controller, and sensors to detect faults, allowing seamless transition to a safe position using the secondary power source and windings in case of primary system failures, ensuring continued operation of valves or pumps.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a single power source and motor controller are used, then the device complexity is reduced, but the reliability deteriorates due to inability to tolerate failures
Solution Approach 1:
The power source is segmented into primary and secondary independent power sources. The motor controller is segmented into primary and secondary independent controllers. This segmentation allows the system to tolerate failures by switching to backup components, resolving the contradiction between reliability and complexity by distributing functions across multiple independent segments.
Solution Approach 2:
Different parts of the system have different functions: primary power source and controller for normal operation, secondary power source and controller for fault tolerance. This local differentiation allows the system to maintain simplicity in normal operation while providing reliability when needed, resolving the contradiction between device complexity and reliability.
2Reliability
If redundant power sources and controllers are added for fault tolerance, then the reliability is improved, but the device complexity increases
Solution Approach 1:
The primary and secondary power sources and controllers are merged into a single integrated actuator assembly. This merging allows the redundant components to share a common housing and control architecture, reducing overall system complexity while maintaining fault tolerance capabilities, thus resolving the contradiction between reliability improvement and complexity increase.
Solution Approach 2:
The secondary power source and controller are designed to be universal backups that can take over any function of the primary components. This multi-functionality allows a single redundant set of components to provide comprehensive fault coverage, improving reliability without proportionally increasing the number of components needed.
3Reliability
If the actuator is designed to always return to safe position upon fault detection, then the safety is improved, but the loss of time occurs during the transition
Solution Approach 1:
The actuator is pre-configured with secondary power sources and controllers that are ready to immediately take over when faults are detected. This preliminary preparation of backup systems eliminates delays in the failover process, allowing the actuator to return to safe position quickly while maintaining safety, thus resolving the contradiction between safety improvement and time loss.
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 high reliability, enabling the actuator to move to a safe position even with single element failures, meeting safety standards and minimizing downtime in harsh environments.
Implementation Method 1
an electric motor (19, 119) operatively configured to connect to a primary power supply (42, 142)... the stator (20) and a mover (21) mounted for movement relative to one another
Data Source
AI summary
An electric motor assembly comprising a housing containing a secondary power source, a motor driver, an electric motor, power sensors to sense faults in a primary power supply and the secondary power source, primary and secondary winding sensors configured to sense faults in a primary winding and a secondary winding of the electric motor, the motor driver comprising a primary controller to control the primary winding in a normal operation mode and a secondary motor controller operatively configured to control at least one of the primary winding and/or the secondary winding in a secondary operation mode, the secondary motor controller configured to drive the motor to a safe position using the secondary winding in the event of a sensed fault in the primary winding and to drive the motor to the safe position using the secondary power source in the event of a sensed fault in the primary power source.