DC Link Ripple Monitoring for Permanent Magnet Generator Faults
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Solution Overview
Problem
Conventional methods for detecting short or open permanent magnet generator (SOPMG) faults require additional circuitry and board space, which can be limited in certain applications, and are unable to detect DC link rectifier diode failures effectively.
Innovation Solution
A method and system that utilize a DC link monitor to measure voltage across the DC link when the generator exciter is inactive and the permanent magnet is active, detecting abnormal ripple content to identify SOPMG and rectifier diode faults using filters to isolate frequencies associated with known fault conditions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional methods use additional circuitry and separate voltage sensing to detect SOPMG faults, then fault detection capability is improved, but device complexity and board space increase
Solution Approach 1:
The DC link monitor is designed to perform multiple functions: it detects SOPMG faults by analyzing ripple content, monitors DC link voltage, and detects rectifier diode failures. This multi-functional approach eliminates the need for separate dedicated sensing circuitry for PMG fault detection, thereby reducing device complexity and board space while maintaining improved fault detection capability
Solution Approach 2:
The patent combines the SOPMG fault detection function with the existing DC link monitor circuitry. Instead of using separate circuitry for PMG fault detection, the solution merges this function into the DC link monitor by analyzing the ripple content on the DC link, which reduces the number of components and simplifies the overall system architecture
2Reliability
If conventional methods use separate voltage sensing away from DC link, then SOPMG fault detection is achieved, but board space and connections increase
Solution Approach 1:
The DC link monitor serves multiple purposes including SOPMG fault detection, DC link voltage monitoring, and rectifier diode fault detection. By making this existing component multi-functional, the patent eliminates the need for additional dedicated sensing circuitry that would occupy extra board space, thereby achieving improved SOPMG fault detection without increasing board area
Solution Approach 2:
The patent extracts the SOPMG fault detection capability from a separate dedicated sensing system and integrates it into the existing DC link monitor. By taking out the fault detection function and embedding it within the DC link monitor through ripple content analysis, the solution reduces the need for additional connections and board space while maintaining effective SOPMG fault detection
3Measurement precision
If conventional methods cannot detect rectifier diode failures, then SOPMG fault detection is focused, but measurement precision for other faults is insufficient
Solution Approach 1:
The DC link monitor is designed to detect multiple fault types including SOPMG faults and rectifier diode failures by analyzing different characteristics of the DC link voltage. By making the monitor multi-functional and capable of identifying various fault conditions through ripple content analysis, the patent achieves both precise SOPMG fault detection and expanded capability to detect rectifier diode failures
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
This approach reduces the need for additional circuitry, minimizes board space, and effectively detects SOPMG and rectifier diode faults, enhancing generator reliability and reducing weight and connections within the system.
Implementation Method 1
detecting abnormal ripple content associated with one or more DC link rectifier diodes on the DC link with the DC link monitor
Implementation Method 2
isolating, using a filter, the abnormal ripple content at a frequency associated with a known SOPMG fault condition frequency to detect the SOPMG fault condition
Data Source
Figure 1
AI summary
In accordance with at least one aspect of this disclosure, a method can include measuring a voltage across a DC link of a generator system when a generator exciter is inactive and a generator permanent magnet is active, and detecting a short or open permanent magnet generator (SOPMG) fault condition in the generator system with a DC link monitor operatively connected to measure the voltage across the DC link.