Aircraft EMS Redundancy for HVDC LRU Isolation Control
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Solution Overview
Problem
Existing energy management systems for aircraft propulsion face challenges in integrating electric motors and hybrid electric power systems due to higher power requirements and stringent safety certification standards.
Innovation Solution
The proposed energy management system (EMS) includes redundant control paths and communication interfaces to connect with line replaceable units (LRUs), enabling independent determination of electrical isolation or connection to a high voltage DC link for propulsion, thus achieving a low probability of catastrophic failure.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If redundant control paths are implemented to independently determine electrical isolation of LRUs, then the probability of catastrophic failure is reduced to less than 10^-9, but the device complexity increases
Solution Approach 1:
The control system is segmented into multiple independent control paths, each capable of independently determining whether to electrically isolate an LRU from the HVDC link. This segmentation allows the system to distribute the safety-critical decision-making across separate pathways, reducing the probability that a single point of failure could cause catastrophic system failure.
Solution Approach 2:
The system implements beforehand cushioning by pre-establishing redundant control paths that can independently execute isolation decisions. This preparatory measure ensures that if one control path fails, the redundant path is already in place to prevent catastrophic failure, thereby cushioning against the worst-case scenario before it can occur.
2Reliability
If extensive testing is conducted to meet strict safety certification requirements, then the system reliability is improved, but the time and resources required for certification increase
Solution Approach 1:
The system performs preliminary actions by implementing a predetermined range verification mechanism for sensor information before full system operation. Each sensor's data is checked against predetermined ranges as a preliminary safety check, which simplifies subsequent certification testing by demonstrating that basic safety checks are already embedded in the system architecture.
3Measurement precision
If sensor information is verified to be within predetermined ranges before control decisions, then measurement precision is improved, but the processing time and system complexity increase
Solution Approach 1:
The system applies parameter changes by transforming continuous sensor data into discrete validation states (within predetermined range or outside range). This parameter transformation simplifies the control logic by converting complex continuous measurement verification into binary decision points, reducing processing complexity while maintaining measurement precision.
Data Source
AI summary
An energy management system (EMS) for an aircraft is provided. The aircraft may have one of a plurality of propulsion systems such as a parallel hybrid electric propulsion system, a parallel turbo electric propulsion system, an electric propulsion system, a turbo electric propulsion system and a turbo hybrid electric propulsion system. The EMS comprises redundant control paths for controlling safety critical operation. Each redundant control path is configured to independently determine whether to electrically isolate a line replaceable unit (LRU) from a high voltage DC link (HVDC link) based on status information from the LRU. The isolation is based on the independent determination. The HVDC link is used for propulsion. The number of the redundant control paths and components may be depending on the type of the propulsion system.