Switch Box Bus Bar Layout for Compact Overcurrent Detection
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing switch boxes in vehicle power supply systems face challenges in detecting overcurrents without increasing size, as traditional methods like shunt resistors and current sensors lead to size increments and heat generation issues, compromising temperature requirements and detection accuracy.
Innovation Solution
A switch box design featuring a magnetic sensor mounted on a circuit substrate between the bus bar and the circuit substrate, detecting the magnetic field generated by current flowing through the bus bar, with optional shield plates and strategic placement to enhance detection accuracy and reduce noise interference, allowing for precise overcurrent detection without increasing the switch box's size.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a shunt resistor is provided to monitor voltage drop and detect overcurrent, then overcurrent detection capability is improved, but the size of the switch box increases
Solution Approach 1:
The patent replaces the traditional shunt resistor (electrical component) with a magnetic sensor that detects the magnetic field generated by current flow. This substitution eliminates the need for a separate shunt resistor while maintaining overcurrent detection capability, thereby preventing size increase in the switch box.
Solution Approach 2:
The patent introduces a magnetic field as an intermediary between the current flow and the detection mechanism. Instead of directly measuring voltage drop with a shunt resistor, the system uses the magnetic field generated by current flow as a mediator that can be detected by the magnetic sensor, enabling indirect but effective overcurrent detection.
2Reliability
If a shunt resistor is provided to detect overcurrent, then overcurrent protection is improved, but heat generation increases and temperature requirements cannot be satisfied
Solution Approach 1:
The patent replaces the shunt resistor with a magnetic sensor, eliminating the resistive element that generates heat through I²R losses. The magnetic sensor detects current indirectly through magnetic field measurement, which does not involve significant energy dissipation, thereby maintaining temperature requirements while preserving overcurrent protection capability.
3Measurement precision
If a current sensor such as a current transformer is provided to detect current, then overcurrent detection capability is improved, but the size of the switch box increases
Solution Approach 1:
The patent replaces bulky current sensors like current transformers with a compact magnetic sensor. The magnetic sensor directly detects the magnetic field generated by current flow in the bus bar, eliminating the need for additional winding structures and magnetic cores required by current transformers, thereby maintaining detection capability while reducing size.
4Measurement precision
If the magnetic sensor is disposed in the gap between the circuit substrate and the bus bar, then detection accuracy is improved without increasing size, but the structure becomes more complex
Solution Approach 1:
The patent positions the magnetic sensor in the gap dimension between the circuit substrate and the bus bar, utilizing the vertical space that already exists in the assembly. This spatial arrangement allows the sensor to be close to the current-carrying conductor for accurate detection without adding horizontal dimensions or increasing the overall footprint of the switch box.
Solution Approach 2:
The gap space between the circuit substrate and bus bar, which would otherwise be empty or filled with insulation material, is utilized for mounting the magnetic sensor. This multi-functional use of existing space serves both mechanical support and sensing functions without requiring additional structural elements, thereby limiting the increase in device complexity.
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
The solution enables high-accuracy current detection and prevention of overcurrents without enlarging the switch box, protecting the switching elements while maintaining temperature requirements and reducing noise interference, thus enhancing compatibility with various vehicle installations.
Implementation Method 1
a magnetic sensor that is mounted on the circuit substrate to detect a magnetic field generated due to a current flowing into the bus bar
Data Source
AI summary
A switch box includes a circuit substrate having a conductor pattern, a switching element that is mounted on the circuit substrate, a bus bar having a current input and output portion formed at one end thereof and a mounting portion formed at the other end thereof, the mounting portion being connected to the conductor pattern of the circuit substrate so as to be electrically conducted to the switching element through the conductor pattern, and a magnetic sensor that is mounted on the circuit substrate to detect a magnetic field generated due to a current flowing into the bus bar. The magnetic sensor is disposed in a gap formed between the circuit substrate and the bus bar.