Contactor Voltage Threshold Monitoring for EV Bus Fault Detection
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Solution Overview
Problem
In multi-high voltage bus systems of hybrid or electric vehicles, existing fault detection methods fail to accurately and timely identify issues with contactors, leading to potential energy transfer failures and increased risk of electrical faults.
Innovation Solution
A vehicle bus system controller initiates pre-charge of a battery terminal only when voltages across contactors exceed specific thresholds, generating notifications and preventing pre-charge initiation if thresholds are not met, thereby ensuring safe and efficient energy transfer.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If existing fault detection methods are used in multi-high voltage bus systems, then the system structure remains simple, but fault detection accuracy and timeliness deteriorate, leading to potential energy transfer failures and increased risk of electrical faults
Solution Approach 1:
The system performs preliminary fault detection by monitoring contactor states and voltages before energy transfer operations commence. The controller checks contactor closure states and voltage levels across bus terminals in advance, identifying potential faults before they can cause energy transfer failures or electrical hazards
Solution Approach 2:
The system implements continuous feedback monitoring of contactor states and bus terminal voltages. The controller receives real-time status information from contactors and voltage sensors, compares readings against expected parameters, and generates fault notifications when deviations are detected, enabling timely corrective action
2Reliability
If voltage threshold monitoring is implemented for contactor pre-charge verification, then fault detection capability improves, but the control logic and measurement requirements become more complex
Solution Approach 1:
The system monitors voltage parameters across bus terminals and compares them against predefined threshold values. When voltage differences across contactors exceed specified thresholds, the controller identifies this as indicative of a fault condition and prevents unsafe energy transfer operations
Solution Approach 2:
The controller serves as an intermediary between contactor actuators and energy transfer operations. It mediates the pre-charge process by verifying contactor states and voltage levels before authorizing main contactor closure and energy transfer, acting as a safety gate that prevents direct connection without proper verification
Data Source
AI summary
A vehicle bus system includes a controller programmed to, after issuing a command to close first and second contactors, wherein the first and second contactors are arranged to share a first terminal of a battery, the first contactor is configured to power a first load when closed, and the second contactor is configured to power a second load when closed, initiate pre-charge of a second terminal of the battery in response to respective first and second voltages across the first and second contactors exceeding corresponding first and second closed-state voltage thresholds, and generate a notification and preclude initiation of the pre-charge in response to one of the first and second voltages being less than the corresponding first and second closed-state voltage thresholds.