Battery Contactor Chatter Detection Under Load
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Solution Overview
Problem
Contactors in battery systems experience undesirable chattering events, which can lead to damage and safety risks when under load, and existing technologies do not effectively address this issue.
Innovation Solution
A method and controller are implemented to detect chattering events in contactors by monitoring their open/close cycles and current thresholds, and in response, take corrective actions such as commanding the battery to an OFF state, providing operator indications, and potentially entering lockout mode to prevent further damage.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If contactors are commanded to frequently open under load during testing, then contactor operational reliability is improved, but contactor chattering occurs causing damage and safety risks
Solution Approach 1:
The system performs preliminary detection of chattering events by monitoring contactor state transitions before they can cause damage. The controller counts the number of times the contactor opens and closes within a predetermined time period, and if the count exceeds a threshold, the system takes preventive action by commanding the contactor to close and preventing further opening commands, thereby preventing harm before it occurs.
Solution Approach 2:
The system implements continuous feedback monitoring of contactor state transitions. The controller detects each opening and closing event of the contactor and uses this feedback information to determine whether chattering is occurring. Based on this feedback, the controller dynamically adjusts its control strategy by limiting further contactor operations when chattering is detected, thus resolving the contradiction between operational reliability and preventing harmful chattering.
2Strength
If contactor chattering is detected and contactor operations are limited, then contactor damage is prevented, but contactor operational flexibility deteriorates
Solution Approach 1:
The system applies partial limitation on contactor operations rather than complete prohibition. When chattering is detected, the system limits further opening commands but allows the contactor to remain closed and functional for normal operations. This partial action approach protects the contactor from damage while maintaining sufficient operational flexibility for legitimate testing and normal vehicle operation.
Solution Approach 2:
The system uses periodic monitoring of contactor state transitions to detect chattering events. By counting transitions within predetermined time periods and comparing against thresholds, the system can distinguish between normal operational cycling and harmful chattering. This periodic detection approach maintains operational flexibility during normal conditions while providing protection when chattering is detected.
Data Source
AI summary
A method for controlling at least one contactor associated with at least one battery module, the at least one battery module being switchable between an ON state and an OFF state, the method including: determining whether the at least one battery module is in the ON state; if the at least one battery module is in the ON state, monitoring the at least one contactor for a chattering event; and if the chattering event occurs, at least one of: commanding the at least one battery module to the OFF state, providing an indication to an operator of the at least one battery module, and evaluating whether to place the at least one battery module in lockout.