Vehicle Contactor Control Logic for High Voltage Circuit Reliability
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Solution Overview
Problem
High voltage electrical systems in vehicles face challenges in effectively controlling contactors, particularly in scenarios where valid commands are not received promptly, leading to potential power disruptions and contactor malfunctions due to inadequate voltage conditions.
Innovation Solution
A method for controlling contactors in high voltage electrical circuits that involves monitoring for valid commands, utilizing timers to manage contactor states, sensing low voltage circuit voltages to prevent damage, and determining faults by comparing voltages across contacts, with signaling of issues to users.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a timer-based control method is implemented to prevent unnecessary power disconnections, then contactor reliability is improved, but device complexity increases due to additional timing logic and monitoring requirements
Solution Approach 1:
The patent implements preliminary action by using a timer to anticipate and prevent potential contactor malfunctions before they occur. The timer monitors the duration of contactor closure and proactively opens the contactor if the closed position is maintained longer than expected, preventing unnecessary power disconnections and potential damage before they can happen.
Solution Approach 2:
The patent employs feedback mechanisms through continuous monitoring of contactor state and timer values. The control system receives feedback about whether the contactor is in an expected state and adjusts its behavior accordingly, opening the contactor when the timer indicates an abnormal duration or when the contactor fails to open when commanded.
2Object-affected harmful factors
If voltage sensing and threshold comparison are added to protect against voltage-related damage, then contactor protection is improved, but device complexity increases due to additional sensing and comparison logic
Solution Approach 1:
The patent applies preliminary anti-action by sensing voltage levels before commanding the contactor to close and comparing the sensed voltage against predetermined thresholds. If the voltage is below the threshold, the close command is inhibited, preventing contactor closure under unsafe voltage conditions that could cause damage.
Solution Approach 2:
The patent introduces voltage sensing and threshold comparison as intermediary steps between the control command and the actual contactor operation. These intermediaries evaluate voltage conditions and only permit contactor closure when conditions are safe, acting as a protective mediator in the control sequence.
3Reliability
If fault detection and signaling mechanisms are implemented to promptly signal issues, then system safety is improved, but device complexity increases due to additional fault monitoring and signaling components
Solution Approach 1:
The patent implements feedback through continuous monitoring of contactor state and comparison with expected behavior. When the contactor fails to open when commanded or remains closed beyond the expected duration, the system detects the fault and signals it to the driver, providing real-time feedback about system status and abnormalities.
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 ensures reliable operation of contactors by preventing unnecessary power disconnections, protecting against voltage-related damage, and promptly signaling faults, thereby enhancing the stability and safety of high voltage electrical systems in vehicles.
Implementation Method 1
Typically, a coil, i.e., an electromagnet, is utilized to close the contactor
Data Source
AI summary
Methods of controlling a contactor in a high voltage electrical circuit of a vehicle include delaying a contactor opening if a valid open command is not received, inhibiting closing of a contactor if a low voltage circuit voltage is not sufficient to close the contactor, and determining a fault in the opening of a contactor based on voltages sensed on the contacts of the contactor.