Fault Tolerant Generator With Isolated Subsystems
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Solution Overview
Problem
Existing generator and starter/generator systems experience significant torque ripple when operating in fault mode due to unbalanced machine loads, which can cause damage to the machine, drive system, and prime mover.
Innovation Solution
The system is designed with physically and electrically isolated operating subsystems, each comprising a machine phase and corresponding power converter, ensuring balanced electrical loads and low torque ripple during fault conditions by disabling faulty subsystems and redistributing load among remaining balanced subsystems.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If redundant elements are configured in the machine and power controller to provide fault tolerant operation, then reliability is improved, but device complexity increases
Solution Approach 1:
The machine is divided into multiple independent phases (e.g., three phases), each with its own isolated windings and associated power converter. This segmentation allows individual phases to be isolated upon fault occurrence, enabling the remaining healthy phases to continue operation without being affected by faults in other phases, thus providing fault tolerance while managing complexity through modular design.
2Reliability
If the generator operates in fault mode using redundant elements, then reliability is maintained, but torque ripple increases significantly
Solution Approach 1:
By segmenting the machine into independent phases with isolated windings, the system can isolate faulty phases and continue operation with remaining healthy phases. Each phase operates independently with its own balanced electrical load through dedicated power converters, which prevents the unbalanced loading that would otherwise occur in traditional systems and causes torque ripple.
Solution Approach 2:
The system changes the operational parameters by using separate power converters for each phase that can independently control the electrical load. This allows each operating subsystem to maintain balanced electrical loading even when operating in fault mode with reduced capacity, thereby minimizing torque ripple while maintaining reliability.
3Reliability
If multiple isolated phases are used for fault tolerance, then reliability is improved, but manufacturing complexity increases
Solution Approach 1:
The machine employs segmented windings arranged in distinct phases that are electrically isolated from each other. This segmentation approach, while providing fault tolerance, requires careful manufacturing processes to ensure proper isolation between phases. The associated power controllers are also segmented into separate power converters for each phase, which can be manufactured and tested independently before assembly, potentially easing the overall manufacturing process despite the increased number of components.
Data Source
AI summary
A fault tolerant generator apparatus includes subsystems isolated from each other, so that the generator may operate in a fault mode with low torque ripple. The apparatus comprises a machine and a power controller unit. In an embodiment, the machine has a plurality of electrical three phase windings and the power controller unit has a plurality of power converters. Each three phase winding of the machine is coupled to a separate corresponding power converter to form an operating subsystem. The operating subsystems are physically and electrically isolated from each other to provide fault tolerant operation of the apparatus. Accordingly, each of the operating subsystems is effective to provide a balanced electrical load for the machine.