Undervoltage Protection Logic for Modulating POR Voltage
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Solution Overview
Problem
Conventional undervoltage protection systems fail to effectively address modulating undervoltage conditions caused by GCU regulation failures, leading to power quality issues in aerospace applications.
Innovation Solution
A method and system for detecting modulating undervoltage states with transients above a threshold, using a controller with latches and time delays to trigger protection measures such as opening relays or deploying a ram air turbine, and implementing redundant processes for backup reliability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional undervoltage protection compares POR voltage to a predetermined level with time delay, then the protection is simple to implement, but it fails to detect modulating undervoltage states where voltage oscillates above and below the threshold
Solution Approach 1:
The protection logic is segmented into multiple independent latches (first latch for detecting undervoltage condition, second latch for triggering protection) with distinct functional responsibilities. This segmentation allows the system to detect modulating undervoltage states reliably while maintaining manageable complexity through modular design.
Solution Approach 2:
The first latch is set in advance when voltage falls below the threshold, preparing the system to trigger protection. This preliminary action allows the system to respond quickly to modulating undervoltage conditions without requiring complex real-time analysis, improving detection accuracy while keeping the logic relatively simple.
2Speed
If the protection triggers immediately when voltage falls below threshold, then the response is fast, but it causes nuisance trips during normal voltage modulation
Solution Approach 1:
The first latch is set in advance when voltage falls below the threshold, preparing the system for potential protection triggering. This preliminary action enables fast response when genuine undervoltage occurs while allowing the second time delay mechanism to filter out transient modulations, thus reducing false trips.
Solution Approach 2:
The system dynamically adjusts its response based on the duration of the undervoltage condition. The second time delay is activated only after the first latch is set, creating a dynamic response that distinguishes between transient voltage drops (normal operation) and sustained undervoltage (protection needed), balancing speed and reliability.
3Reliability
If multiple latches with different time delays are used to detect modulating undervoltage, then the detection accuracy improves, but the device complexity increases
Solution Approach 1:
The detection mechanism is divided into two distinct latches with separate functions: the first latch detects the undervoltage condition, and the second latch triggers the protection after a delay. This segmentation improves detection accuracy for modulating conditions while keeping each latch relatively simple, managing overall complexity through functional division.
Solution Approach 2:
The latch mechanism serves multiple functions: detecting undervoltage conditions, filtering transient modulations through time delays, and triggering protection. This multi-functionality reduces the need for separate dedicated components for each function, thereby managing complexity while improving detection reliability.
4Productivity
If the first latch is reset quickly when voltage recovers, then the system returns to normal operation fast, but it may not trigger protection during sustained modulating undervoltage
Solution Approach 1:
The reset condition for the first latch is dynamically defined: it resets when voltage rises above the threshold AND remains there for a specified time delay. This dynamic condition allows fast recovery during transient drops while ensuring that sustained modulating undervoltage conditions (where voltage repeatedly fails to stay above the threshold) will trigger the second latch and activate protection.
Solution Approach 2:
The second latch is set in advance when the first latch fails to reset within the expected time delay, preparing the system to trigger protection. This preliminary action ensures that sustained modulating undervoltage conditions are caught and protected against, while allowing normal transient recoveries to proceed quickly.
Data Source
AI summary
A method includes detecting a modulating undervoltage state having transients above an undervoltage threshold and triggering a protection upon detecting the modulating undervoltage state. The method can include detecting a steady state undervoltage condition, wherein triggering a protection includes triggering the protection upon detecting the steady state undervoltage condition or the modulating undervoltage state. A system includes a power source including a feedback sensor at a point of regulation (POR) of the power source configured to generate feedback indicative of voltage at the POR. A controller is operatively connected to receive the feedback. The controller includes controller logic that is configured perform a method as described above.