Shielded DC Lead Assembly for Parallel Arc Detection
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Solution Overview
Problem
Existing DC electrical systems in motor vehicles face challenges in reliably detecting and interrupting safety-critical error conditions, such as parallel arcs, due to the limitations of conventional fuses and overcurrent protection methods, which can lead to delayed or incomplete disconnection during faults, posing risks to the system.
Innovation Solution
The solution involves designing the shield of the supply line as a sensor conductor connected to the inner conductor via a terminating resistor and to the basic potential via a detection resistor, forming a voltage divider that allows for the detection of fault conditions like parallel arcs, enabling the evaluation circuit to actuate a separating element to interrupt the circuit safely and reliably.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional fuses or simple electronic overcurrent protection are used, then the device complexity is low, but the reliability of arc detection and interruption is insufficient
Solution Approach 1:
The shield is designed to serve dual functions: electromagnetic shielding and sensor conductor for arc detection. By connecting the shield to the inner conductor via a terminating resistor and to ground via a detection resistor, the shield becomes part of the detection circuit, enabling arc detection without additional sensor conductors while maintaining its protective function
Solution Approach 2:
The cable structure itself provides detection capability through its inherent components. The shield, terminating resistor, and detection resistor form a voltage divider that automatically detects arcs through voltage changes, eliminating the need for separate detection systems and enabling self-monitoring of the cable integrity
2Reliability
If additional sensor conductors are added for arc detection, then the detection capability is improved, but the manufacturing cost and device complexity increase
Solution Approach 1:
The shield performs both electromagnetic shielding and sensor functions simultaneously. By utilizing the existing shield structure and adding only resistors, the system achieves arc detection capability without requiring additional sensor conductors, thereby reducing manufacturing complexity and cost
Solution Approach 2:
The detection function is merged with the existing shield structure. The shield is electrically connected to form a voltage divider with the terminating and detection resistors, combining the protective shielding function with the detection function in a single integrated structure
3Measurement precision
If the shield is designed as a sensor conductor with voltage divider, then the detection precision for parallel arcs is improved, but the device complexity increases
Solution Approach 1:
The shield serves as both shield and sensor, with the voltage divider formed by the terminating and detection resistors enabling precise voltage measurement that indicates arc conditions. This multi-functional design achieves precise detection without adding separate sensor systems
Solution Approach 2:
The voltage divider provides continuous voltage feedback to the evaluation circuit that reflects the electrical state of the cable. Changes in voltage due to arc formation are immediately detected and can trigger isolating elements to interrupt the circuit, providing real-time monitoring and response
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 allows for effective and timely detection of safety-critical error states, including parallel arcs, without the need for additional sensor conductors, providing a cost-effective and robust solution that can monitor multiple consumers and reduce the risk of consequential damage from faults.
Implementation Method 1
the shield is connected on the load side to the inner conductor via a terminating resistor (RA) which has a high resistance compared to a load resistor and is connected on the source side to the ground potential via a detection resistor (RS) which has a low resistance compared to the terminating resistor, wherein the safety electronics comprises an evaluation circuit and the evaluation circuit taps a detection voltage at the detection resistor
Implementation Method 2
the evaluation circuit taps a detection voltage at the detection resistor in order to detect at least one first fault condition, in particular a parallel arc, based on the measured detection voltage
Data Source
Figure 1a~2b
Figure 3~4
Figure 5~6
AI summary
The invention relates to a line assembly for a DC voltage onboard electrical system of a motor vehicle, comprising: - a power source (11), - at least one load (L); - a supply line (5) which has a shielding (3) and an inner conductor (1) and which is connected to the power source on the source side and to the at least one load (L) on the load side; and - an electronic safety system (7) which is connected between the power source (11) and the supply line and which comprises an actuatable separating element (8). The aim of the invention is to enable a more effective detection and a reliable elimination of safety-critical malfunctions and to facilitate a production which is as inexpensive as possible as well as a robust design. According to the invention, this is achieved in that the shielding (3) is designed in the form of a sensor conductor in that the shielding (3) is connected to the inner conductor (1) on the load side via a terminating resistor (RÄ) and to the ground potential (M) on the source side via a detection resistor (Rs) which is low-ohmic in comparison to a load resistor (6), wherein the electronic safety system (7) comprises an analysis circuit (9), and the analysis circuit (9) taps a detection voltage on the detection resistor (Rs) in order to detect malfunctions.