Upfitter Power Relay Reclosure for Vehicle Load Priority
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Solution Overview
Problem
Solid-state relays in vehicle power distribution systems are prone to frequent switching under load, leading to heat generation and reliability issues, especially when upfit loads create power surges, causing tripping and requiring manual intervention.
Innovation Solution
A power distribution circuit with sensors monitoring voltages and currents, selectively controlling a solid-state relay to open and reclose based on voltage stabilization and current adjustments, and providing user warnings and priority control to manage upfit loads.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a solid-state relay is used to protect against upfit power surges, then reliability of vehicle electrical system is improved, but the relay trips frequently under load causing operation interruption
Solution Approach 1:
The system performs preliminary detection of voltage conditions before the relay trips. The controller monitors voltage at the junction and main power bus, and only allows reclosure when voltage has stabilized, preventing premature reclosure that would cause immediate tripping again.
Solution Approach 2:
The system uses feedback from voltage sensors to control relay reclosure. The controller continuously monitors voltage at the junction and main power bus, and uses this feedback to determine when conditions are safe for reclosure, creating a closed-loop control system that prevents unnecessary tripping.
2Productivity
If the solid-state relay is reclosed immediately after tripping, then productivity is improved by restoring power quickly, but heat generation and stress on the relay increase
Solution Approach 1:
The system implements a preliminary waiting period after tripping before attempting reclosure. The controller waits for voltage to stabilize at predetermined levels, ensuring that the relay is not reclosed during conditions that would cause immediate tripping or excessive stress.
Solution Approach 2:
The system maintains continuous voltage monitoring during the post-trip period. Rather than immediately reclosing or leaving open, the controller continuously checks voltage conditions and recloses only when continuous stable voltage is confirmed, ensuring uninterrupted protection while minimizing downtime.
3Reliability
If voltage is monitored and adjusted for relay reclosure, then reliability is improved by preventing premature reclosure, but device complexity increases
Solution Approach 1:
The power distribution controller performs multiple functions: it monitors voltage at the junction, monitors voltage at the main power bus, controls the solid-state relay, and provides protection against power surges. By making the controller multi-functional, additional voltage monitoring capability is added without requiring a separate dedicated monitoring device.
Solution Approach 2:
The voltage monitoring function is merged with the relay control function in a single integrated controller. The same controller that manages relay operation also performs voltage detection and decision-making, consolidating multiple functions into one device rather than using separate components.
Data Source
AI summary
A motor vehicle electrical distribution system includes an upfitter power supply subsystem with overcurrent protection for tripping (opening) a solid-state relay when current drawn from a main electrical source by the upfitter subsystem impacts other priority electrical loads of the vehicle. Warnings/alerts are generated to inform the user (e.g., driver) of the tripping events, which may include real-time graphing of a recent history of events. In order to restore power to the upfitter subsystem, a voltage supplied by a supplemental battery (i.e., vehicle start-up battery) to the upfitter subsystem is monitored. If the voltage stabilizes then a voltage from the main electrical source is intentionally dropped to the stabilized value and the solid-state relay is re-closed. Then the main voltage is ramped back up to its nominal value. An automatic reset time may be added to delay the reclosing if the solid-state relay has been operated excessively.