Contactor Weld Detection Using Exciters and Resonant Signals
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Solution Overview
Problem
During the testing of rechargeable batteries in electric vehicles, welded contactors can cause short circuits and fires due to improper reconfiguration, necessitating a reliable method to detect contactor welds.
Innovation Solution
A system and method for contactor weld detection using exciters and detectors to inject and measure excitation signals, determining the status of contactors by analyzing impedance reflections, and utilizing a controller to identify welded contacts.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If manual contactor inspection methods are used during battery testing, then device complexity is reduced, but reliability of contactor status detection deteriorates leading to safety hazards
Solution Approach 1:
The patent replaces manual visual inspection and mechanical contactor operation with an automated electrical detection system. The system uses exciters to generate test signals and detectors to measure impedance changes, automatically determining contactor status without human intervention. This substitution of mechanical/manual processes with electrical measurement systems resolves the contradiction by improving reliability through consistent automated detection while managing complexity through standardized measurement procedures.
Solution Approach 2:
The detection system enables the contactor assembly to self-diagnose its own status. By incorporating exciters and detectors that automatically measure impedance changes across contactor terminals, the system allows the contactor assembly to identify its own welded or stuck contacts without external manual inspection. This self-service capability improves reliability by providing continuous automated monitoring while reducing the need for complex external detection equipment.
2Reliability
If automated exciter-detector systems are deployed for contactor weld detection, then reliability of contactor status detection is improved, but device complexity increases
Solution Approach 1:
The patent implements multi-functional contactor assemblies that integrate both operational contactors and detection exciters-detectors within a single unified structure. The same contactor assembly that performs battery testing functions also contains the detection capability. This universality resolves the contradiction by improving weld detection reliability through integrated sensing while reducing overall system complexity by eliminating separate detection equipment and simplifying the test circuit architecture.
Solution Approach 2:
The patent merges the contactor operational function with the weld detection function into a single integrated assembly. The exciters and detectors are incorporated directly into the contactor structure, allowing simultaneous performance of switching operations and status monitoring. This merging resolves the technical contradiction by improving detection reliability through integrated sensing while reducing device complexity by consolidating multiple functions into one assembly rather than requiring separate systems.
3Object-affected harmful factors
If continuous monitoring of contactor status is implemented, then safety against short circuits and fires is improved, but energy consumption increases
Solution Approach 1:
The patent implements periodic impedance measurement cycles rather than continuous monitoring. The exciters are activated at intervals to inject test signals and measure impedance changes across contactor terminals. This periodic action resolves the contradiction by maintaining safety through regular detection of welded contacts that could cause short circuits or fires, while reducing energy consumption by keeping the detection system inactive between measurement cycles rather than operating continuously.
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
Effectively detects welded contactors, preventing short circuits and fires by ensuring proper reconfiguration of test circuits, thereby enhancing safety in battery testing environments.
Implementation Method 1
a plurality of exciters connected to a plurality of first nodes of a test circuit are triggered to inject an excitation signal at an associated first node in the test circuit
Implementation Method 2
a plurality of detectors connected to a plurality of second nodes of the test circuit are triggered to measure a peak value of a resonant signal detected at an associated second node in the test circuit
Data Source
AI summary
A system and method for determining a status of a plurality of contactors is provided. A plurality of exciters connected to a plurality of first nodes of a test circuit are triggered. Each of the plurality of exciters, when triggered, inject an excitation signal at an associated first node in the test circuit. A plurality of detectors connected to a plurality of second nodes of the test circuit are triggered. Each of the plurality of detectors, when triggered, detect a peak value of a resonant signal detected at an associated second node in the test circuit, and provide a digital output by comparing the peak value with a predetermined value. A status of a subset of a plurality of contactors of the test circuit is determined based on the digital output received from each of the plurality of detectors.