Automotive Electronic Switch Overload Protection Strategy
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Solution Overview
Problem
Current protection methods for electronic switches in automotive vehicles are unreliable due to prolonged inhibition of the protection strategy during startup periods, which can lead to untimely outages and fail to distinguish between accidental overloads and current spikes, especially at low power supply voltages, resulting in potential safety hazards.
Innovation Solution
A method that establishes a table of overload intensity values, where for voltages above a predetermined value (VNbat), IS=IT+ΔIc, and for voltages below or equal to VNbat, IS is a constant value, allowing for reduced inhibition times by setting VNbat to a nominal voltage value, such as 14 volts, thereby optimizing the protection strategy.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If the inhibition time is extended to cover all startup periods, then false overloads during startup are avoided, but the protection strategy remains inactive for significant time periods, making it unreliable for short-duration loads
Solution Approach 1:
The patent changes the parameter of overload threshold based on voltage levels. By using a table of voltage-dependent ΔIc values, the system dynamically adjusts what constitutes an overload condition. This allows shorter inhibition times at low voltages while still preventing false overloads, making the protection reliable for short-duration loads like stop lights and indicator lights.
2Device complexity
If a fixed inhibition period is used for all voltage levels, then the protection strategy is simple to implement, but it cannot adapt to the varying startup durations at different power supply voltages
Solution Approach 1:
The patent implements parameter changes by using a pre-defined table of voltage-dependent compensation values (ΔIc) rather than complex real-time calculations. This approach maintains relative simplicity while achieving adaptability to different voltage levels and their corresponding startup durations.
Solution Approach 2:
The patent applies preliminary action by pre-calculating and storing the compensation values (ΔIc) in a table for various voltage levels. This allows the system to quickly retrieve appropriate thresholds during operation without performing complex real-time calculations, balancing simplicity with adaptability.
Data Source
AI summary
A method for protecting an electronic switch incorporated in an automotive vehicle in order to control the power supply of an electric load, the method including implementing a protection strategy, based on the use of a table of overload intensity values IS, intended to make it possible to detect and count the overshoots of the overload values IS, and to interrupt the operation of the electronic switch beyond a given number of overloads undergone. A table of overload intensities IS is established giving, for values of the power supply voltage that are greater than a predetermined voltage value VNbat, values IS=IT+ΔIc, with ΔIc being identical for all the values, and for values of the power supply voltage that are less than or equal to VNbat, a constant value IS such that IS=IT(VNbat)+ΔIc.