Diode Fault Detection in Brushless Exciter Rectifiers
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Solution Overview
Problem
Existing methods for detecting diode faults in brushless synchronous generators are complex and require multiple sensors, making them inefficient for quick and accurate fault detection in rotating diode rectifiers.
Innovation Solution
A method using a single sensor to measure the voltage across the load and derive the ratio of harmonic frequencies, allowing for the detection of diode faults by comparing the derived values with predetermined ranges to determine if a fault has occurred, thereby distinguishing between open and short circuit faults.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If multiple voltage sensors are used to measure diode voltages and calculate voltage ratios, then fault detection accuracy is improved, but device complexity increases
Solution Approach 1:
The patent extracts the fault detection function from a multi-sensor system and implements it using a single voltage sensor. By measuring only the voltage across the load and deriving harmonic frequency ratios, the system eliminates the need for multiple sensors while maintaining detection capability. This extraction principle reduces device complexity while preserving measurement precision for fault detection.
Solution Approach 2:
The single voltage sensor performs multiple functions: it measures load voltage, extracts harmonic frequency components, calculates voltage ratios, and enables fault detection. This multi-functionality approach allows one sensor to replace what would traditionally require multiple specialized sensors, thereby reducing device complexity while maintaining measurement precision.
2Reliability
If voltage ratio analysis is performed across all operating conditions, then fault detection reliability is improved, but measurement precision requirements increase
Solution Approach 1:
The patent transforms the measurement parameter from absolute voltage values to a ratio of harmonic frequency voltages. This parameter transformation makes the measurement less sensitive to absolute precision requirements while maintaining reliability across varying operating conditions. The ratio-based approach compensates for variations in operating voltage, allowing reliable fault detection without demanding extremely high measurement precision.
Data Source
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AI summary
A method of detecting a diode fault in an AC signal rectifier circuit, the AC signal rectifier circuit including a plurality of diodes, and being arranged to supply a rectified output voltage to a load, wherein the method includes the steps of deriving an operating value indicative of the ratio of the voltage magnitudes of a first harmonic frequency and another harmonic frequency of the rectified output voltage across the load; and determining whether a fault has occurred in one or more diodes on the basis of the derived operating value. The first harmonic frequency is preferably the fundamental harmonic frequency, and/or the another harmonic frequency is preferably the 6th harmonic frequency.