Rail Vehicle Electric Network Fault Detection via Voltage Monitoring
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Solution Overview
Problem
Existing rail vehicle electric networks face challenges in monitoring and detecting faults, particularly short-circuits, when the power converter is disconnected from the permanent magnet machine, as current monitoring methods are inadequate for identifying network issues in this state.
Innovation Solution
A method involving the determination of potential differences along phase lines, using voltage sensors and speed-dependent references to detect deviations, allowing for the identification of network faults even when the power converter is disconnected, and implementing a device with evaluation and interruption units to manage these faults.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If current monitoring methods are used to detect short-circuits in the electric network, then short-circuits can be detected when the power converter is connected to the permanent magnet machine, but network faults cannot be detected when the power converter is disconnected from the permanent magnet machine
Solution Approach 1:
The patent replaces current-based monitoring (which requires closed circuit operation) with voltage-based monitoring using voltage sensors that can detect potential differences even when the circuit is open. This substitution enables fault detection in both connected and disconnected states of the power converter.
Solution Approach 2:
The patent introduces voltage sensors as intermediary devices between the phase lines and the monitoring system. These sensors measure potential differences relative to a reference potential (such as the negative pole of the link circuit capacitor or ground potential) and provide signals that enable fault detection regardless of whether the power converter is connected to the permanent magnet machine.
2Object-affected harmful factors
If the power converter is electrically disconnected from the permanent magnet machine to prevent short-circuit damage, then component destruction is prevented, but monitoring of network faults in the disconnected state becomes impossible with conventional methods
Solution Approach 1:
The patent replaces current-based monitoring (which requires closed circuit operation) with voltage-based monitoring using voltage sensors that can detect potential differences even when the circuit is open. This substitution enables fault detection in both connected and disconnected states of the power converter.
Solution Approach 2:
The patent establishes a monitoring system using voltage sensors and reference potentials that is prepared in advance to detect faults in the machine-side partial network. This preliminary setup ensures that even when disconnection occurs to prevent damage, the monitoring capability remains active and can detect faults that may have caused or resulted from the disconnection.
Data Source
AI summary
The invention relates to a device and a method for monitoring an electric network in a rail vehicle. The electric network includes at least one power converter, at least one permanent magnet machine, and at least one first phase line for the electrical connection of the at least one power converter and the at least one permanent magnet machine. The first phase line is interrupted. A potential difference is determined between a machine-side part of the first phase line and a reference potential and a potential-difference-dependent variable, wherein a speed of the permanent magnet machine and, as a function of the speed, a speed-dependent reference variable are determined. A deviation of the potential-difference-dependent variable from the speed-dependent reference variable is determined, wherein a network fault is detected if the deviation is greater than a predetermined threshold value.