Busbar-Integrated Current Sensor Assembly for Stable Detection
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Solution Overview
Problem
Existing current sensors for motor driving control devices face issues with increased size and manufacturing costs due to the inclusion of a magnetic core, and coreless current detection is prone to significant fluctuations in detected current values due to assembly errors and variations in separation distance between the magnetic detection element and the energization busbar.
Innovation Solution
The control device integrates the energization busbar partially into a case, with the substrate directly fixed to a base member, ensuring high assembly accuracy and reduced variation in separation distance, and allows for adjustment of the current value conversion program after assembly to stabilize detection accuracy.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a magnetic core is provided in the current sensor, then detection accuracy is improved, but device size and manufacturing cost increase
Solution Approach 1:
The patent removes the magnetic core from the current sensor structure, extracting only the essential Hall element for detection. This eliminates the complexity and cost associated with the magnetic core while maintaining detection functionality through direct magnetic field sensing by the Hall element.
Solution Approach 2:
The patent replaces the expensive and complex magnetic core with a simpler, more cost-effective Hall element-based detection system. This substitution reduces manufacturing costs and simplifies the overall device structure while achieving the required detection accuracy.
2Device complexity
If coreless current detection is used without a magnetic core, then device size and cost are reduced, but detection accuracy fluctuates due to assembly errors in separation distance
Solution Approach 1:
The patent performs preliminary action by pre-setting the separation distance between the Hall element and busbar during the assembly process. This preliminary positioning ensures that the detection accuracy is optimized before actual operation, compensating for potential assembly variations and eliminating the need for complex real-time adjustments.
3Measurement precision
If the separation distance between current sensor and busbar is reduced to minimize assembly errors, then detection accuracy improves, but assembly precision requirements increase
Solution Approach 1:
The patent introduces an intermediary structure (support member or mounting bracket) that mediates the positioning between the Hall element and busbar. This intermediary component ensures a precise and stable separation distance without requiring extremely high assembly precision, as the intermediary itself provides the reference geometry for correct positioning.
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 configuration enhances assembly accuracy and detection precision of current values by minimizing fluctuations and vibrations, contributing to stable current sensing in motor driving systems.
Implementation Method 1
a current sensor has a magnetic core and a Hall element (magnetic detection element) arranged in the peripheral area of an energization busbar connected to a power control circuit. This current sensor has a mechanism that amplifies a magnetic field generated due to current flowing through the energization busbar by the magnetic core, and detects the magnetic field amplified by the magnetic core by the Hall element.
Data Source
AI summary
A control device includes an energization busbar, a substrate, a magnetic detection type current sensor, a case, and a base member. A controller is mounted on the substrate. The current sensor is mounted at a position close to the busbar on the substrate and detects a magnetic field caused by current flowing through the busbar. The case accommodates the substrate and the busbar. The case is fixed to the base member. The busbar is partially embedded and fixed in the case. The substrate is directly fixed to the base member.