Battery Charger Chassis Coupling Current Control
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Ground fault circuit interrupters (GFCIs) in automotive vehicles can trip during battery charging due to rapid changes in current and voltage, leading to discontinuation of charging when the chassis coupling current exceeds the trip setting, typically 5 mA.
Innovation Solution
Implementing a controller and battery charger system that controls the rate of change in electrical energy provided to limit the chassis coupling current by gradually increasing or decreasing the current output, with specific rates determined through testing and simulation to avoid exceeding the GFCI trip setting.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If the battery charger rapidly increases or decreases current output to respond to controller commands, then the charging response speed and productivity are improved, but the chassis coupling current exceeds the GFCI trip setting causing charging discontinuation
Solution Approach 1:
The battery charger dynamically adjusts its current output based on real-time conditions. It transitions from static current delivery to dynamic control by monitoring chassis coupling current and adjusting the rate of current change accordingly, allowing the system to respond to controller commands while maintaining GFCI compliance
Solution Approach 2:
The system implements feedback control by monitoring the chassis coupling current generated during battery charging. The battery charger uses this feedback information to adjust its current output rate, preventing GFCI tripping while maintaining efficient charging operation
2Reliability
If the battery charger controls the rate of change in electrical energy to limit chassis coupling current, then the GFCI trip prevention is achieved, but the charging response speed decreases
Solution Approach 1:
The battery charger changes the parameter of current rate of change based on operational conditions. By adjusting this parameter dynamically rather than using a fixed rate, the system prevents GFCI tripping during normal operation while allowing faster response when conditions permit, thus resolving the contradiction between reliability and speed
Data Source
AI summary
An automotive vehicle may include a battery charger that receives electrical energy, via an electrical connection including a ground wire, from an electrical source remote from the vehicle, and outputs the electrical energy to at least one electrical load. The vehicle may also include at least one controller that commands a change in the electrical energy output by the battery charger. The battery charger, in response to the command, may control a rate of change in the electrical energy output such that a coupling current to the ground wire resulting from the change in the electrical energy output by the battery charger has a magnitude less than a predetermined threshold.