Contactor Sequencing via Current Sensing for Arc Mitigation
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Solution Overview
Problem
High voltage electrical systems in vehicles face issues with arcing between contacts when contactors are opened or closed under excessive current, leading to potential damage and performance problems.
Innovation Solution
A method and system that sense current through positive and negative contactors before opening or closing, calculate weighted values based on sensed currents, and determine the order of contactor operation to minimize adverse effects, using sensors and a controller to manage the contactors' operation in response to open or close commands.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Power
If contactors are opened or closed under excessive current, then the electrical system can operate at high power levels, but arcing occurs between contacts causing damage and performance issues
Solution Approach 1:
The system performs preliminary actions by sensing current levels before contactor operation and calculating weighted values in advance. The controller determines the optimal opening/closing sequence beforehand based on current conditions, ensuring contactors are operated in the safest possible sequence before excessive current conditions develop, thereby preventing arcing while maintaining high power operation capability
Solution Approach 2:
The system continuously senses current flowing through each contactor and feeds this information back to the controller. The controller calculates weighted values based on sensed current and uses this feedback to dynamically determine and adjust the opening/closing sequence, allowing the system to adapt to changing current conditions and prevent arcing while maintaining high power operation
2Reliability
If the order of contactor operation is optimized to reduce arcing, then contactor durability is improved, but the system requires complex current sensing and calculation mechanisms
Solution Approach 1:
The system uses the existing current sensing infrastructure already present in the electrical system for other control functions. Rather than adding dedicated sensors solely for contactor sequencing, the system repurposes existing current measurements to calculate weighted values and determine opening/closing sequences, reducing additional hardware complexity while improving reliability
Solution Approach 2:
The system transforms complex multi-parameter current measurements into simplified weighted values that represent the relative safety of opening or closing each contactor. By changing the parameter representation from raw current values to calculated weighted scores, the system simplifies the control logic while maintaining accurate assessment of arcing risk, thereby improving reliability without proportionally increasing complexity
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 risk of arcing by optimizing the order of contactor operation, thereby extending the useful life and serviceability of the electrical system while preventing damage.
Implementation Method 1
Typically, a coil, i.e., an electromagnet, is utilized to close the contactor
Implementation Method 2
sensing current flowing through each contactor
Implementation Method 3
When contactors are opened or closed under excessive current, arcing may occur between the contacts
Data Source
AI summary
A method of controlling positive and negative contactors in a high voltage electrical system includes sensing current flowing through each contactor prior to opening of the contactor and/or after closing of the contactor. A negative contactor weighted value is computed based at least partially on the sensed current flowing through the negative contactor during opening and/or closing. A positive contactor weighted value is computed based at least partially on the sensed current flowing through the positive contactor during opening and/or closing. The order of opening and/or closing of the contactors is determined utilizing at least one of the negative contactor weighted value and the positive contactor weighted value.