Generator Excitation Field Isolation for Redundant Overvoltage Protection
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Solution Overview
Problem
Existing overvoltage protection systems for power generators lack reliability due to a lack of redundancies, leading to detrimental effects on electrical systems during extended overvoltage events, particularly in critical environments like aircraft systems.
Innovation Solution
A redundant overvoltage protection system that monitors regulation voltage inputs and outputs, using multiple detection points and redundant power isolation paths to disconnect the generator excitation field from the power source, employing solid-state switches and relays to prevent overvoltage conditions from affecting the electrical system.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a single overvoltage protection path is used, then the system structure is simple, but the reliability is insufficient
Solution Approach 1:
The protection system is segmented into multiple independent protection paths: a primary protection path using a first solid-state switch and control circuit, and a secondary protection path using a second solid-state switch and fuse. This segmentation ensures that if one path fails, the other can still provide protection, thereby improving reliability without excessive complexity.
Solution Approach 2:
The system implements beforehand cushioning by providing redundant protection mechanisms in advance. The secondary protection path with fuse and second solid-state switch is prepared as a backup before any overvoltage fault occurs, ensuring that protection is available even if the primary path fails.
2Measurement precision
If multiple monitoring points are used, then the detection coverage is improved, but the system complexity increases
Solution Approach 1:
The voltage monitoring function is segmented into multiple independent monitoring points: a first monitoring point that monitors the input voltage to the solid-state switch, and a second monitoring point that monitors the output voltage. Each monitoring point has its own detection circuit, allowing precise local detection without requiring a complex centralized monitoring system.
Solution Approach 2:
The patent introduces intermediary monitoring circuits that act as mediators between the voltage sources and the control system. These intermediary circuits process the voltage signals locally and provide clear fault indications to the control logic, simplifying the overall monitoring architecture while maintaining high detection accuracy.
3Reliability
If redundant protection paths are implemented, then the reliability is improved, but the device complexity increases
Solution Approach 1:
The redundant protection paths are segmented into distinct functional modules: primary protection module with first solid-state switch, secondary protection module with second solid-state switch and fuse, and control module. This modular segmentation allows each module to be optimized independently while maintaining overall system reliability.
Solution Approach 2:
The system uses parameter changes in the solid-state switches (changing their on/off state) and fuse (changing from conductive to open circuit) to provide protection. These parameter changes are controlled by voltage thresholds detected by the monitoring circuits, allowing automatic protection without complex control logic.
Data Source
AI summary
Described is a method including monitoring a point of regulation voltage input to a generator control unit and monitoring a generator output voltage as a backup point of regulation voltage input. The method also includes detecting an overvoltage fault at the point of regulation voltage input, the backup point of regulation voltage input, or both. Additionally, the method includes opening a first solid-state switch (110) in response to detecting the overvoltage fault. Opening the first solid-state switch (110) prevents provision of an input signal (104) to a generator excitation field (102). Further, the method includes opening a generator excitation field relay (112) in response to detecting the overvoltage fault. Opening the excitation field relay (112) also prevents provision of the input signal (104) to the generator excitation field (102).