Series Resistive-Inductive Detection for EV Short Circuits
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Solution Overview
Problem
Existing short-circuit detection methods in electric vehicles are not reliable or fast enough, leading to potential damage from high current increases during short circuits, particularly due to temperature dependencies and varying inductance in the system.
Innovation Solution
A detection device comprising a series circuit of resistive and inductive measuring elements, which measures voltage across the circuit to rapidly detect short circuits and trigger a controllable switching device to interrupt the current flow, without lowering the detection threshold.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Speed
If DE-SAT measurement with coupling diode and voltage divider is used for short-circuit detection, then the triggering threshold can be increased in the event of rapid current rise, but the short-circuit threshold varies considerably due to temperature dependence and aging
Solution Approach 1:
The patent changes the measurement parameter from voltage across semiconductor switch to voltage across a series circuit of resistive and inductive measuring elements. This parameter change eliminates temperature dependence and aging effects while maintaining rapid detection capability through the inductive element's response to di/dt
Solution Approach 2:
The patent replaces the semiconductor-based measurement system (coupling diode, voltage divider) with a passive electrical measurement system (resistive and inductive measuring elements in series). This substitution eliminates the temperature-dependent semiconductor components while preserving the detection function through electromagnetic principles
2Measurement precision
If MOSFET Rdson measurement is used for current detection, then the voltage drop across on-resistance can be measured, but the Rdson value varies by approximately 150% in the temperature range of 25°C to 150°C
Solution Approach 1:
The patent introduces external resistive and inductive measuring elements as intermediaries between the current to be measured and the measurement system. These intermediary elements provide a stable, temperature-independent voltage signal that accurately reflects current changes without being affected by semiconductor temperature characteristics
Solution Approach 2:
The patent segments the measurement function into separate resistive and inductive measuring elements connected in series. The resistive element provides the base voltage signal while the inductive element responds to current changes, separating the measurement from temperature-dependent semiconductor properties
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
Enables very rapid short-circuit detection and quick interruption of current flow, reducing the risk of damage by accurately distinguishing between normal operation and short-circuit conditions, even in low-inductive scenarios.
Implementation Method 1
an inductive measuring element, wherein the resistive measuring element and the inductive measuring element are electrically arranged in a series circuit
Implementation Method 2
a resistive measuring element, wherein the resistive measuring element and the inductive measuring element are electrically arranged in a series circuit
Data Source
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AI summary
The present invention discloses a detection device (100, 200) for detecting a short circuit in a load path (150), comprising an input terminal (101, 201) and an output terminal (102, 202), a resistive measuring element (103, 203, 303), an inductive measuring element (104, 204, 304), wherein the resistive measuring element (103, 203, 303) and the inductive measuring element (104, 204, 304) are electrically arranged in series between the input terminal (101, 201) and the output terminal (102, 202), a measuring device (105, 205) configured to measure a voltage (106, 206) across the series circuit, and a detection device (107, 207) which is connected to the measuring device (105, 205) is coupled and is designed to detect a short circuit in the load path (150) when the measured voltage (106, 206) exceeds a predetermined threshold and to output a corresponding short circuit signal (108, 208).Furthermore, the present invention discloses a switching device, an electrical supply system, a detection method, a method for opening a load path and a method for supplying an electrical load.