Segmented Magnetic Shield for Current Sensor Leakage Cancellation
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Solution Overview
Problem
Current detection systems experience current detection errors due to leakage magnetic fields generated from gaps between magnetic shields, which interfere with the magnetoelectric conversion element, leading to inaccurate current measurement.
Innovation Solution
The current sensor is designed with a configuration of phases having magnetic field detection elements and pairs of magnetic shields, where the shields are stacked with gaps between them to cancel out leakage magnetic fields, ensuring that these fields do not reach the detection element, thereby improving measurement accuracy.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If magnetic shields are provided to shield the magnetic field detection element from external magnetic fields, then the shielding effect is improved, but gaps between the magnetic shields generate leakage magnetic fields that cause detection errors
Solution Approach 1:
The magnetic shield is divided into multiple segments (first magnetic shield and second magnetic shield) with a gap between them. This segmentation allows the leakage magnetic fields from opposite sides of the gap to cancel each other out, reducing the harmful effect on the detection element while maintaining the overall shielding structure.
Solution Approach 2:
The gap between magnetic shields, which initially causes leakage magnetic fields (harm), is designed to produce cancellation effects where leakage fields from opposite sides neutralize each other. This converts the harmful leakage into a beneficial cancellation effect that reduces the net magnetic interference on the detection element.
2Measurement precision
If magnetic shields are stacked with gaps between them, then leakage magnetic fields are canceled out, but the shielding structure becomes more complex
Solution Approach 1:
The magnetic shield is segmented into multiple independent parts (first and second magnetic shields) that can be separately positioned and adjusted. This segmentation enables the gap configuration needed for field cancellation while keeping each individual shield component relatively simple in structure.
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 effectively reduces the impact of leakage magnetic fields on the detection element, allowing for precise detection of currents flowing in each current path, enhancing the accuracy of current measurement.
Implementation Method 1
The semiconductor substrate is provided with a magnetoelectric conversion element for converting a magnetic flux into an electric signal
Implementation Method 2
The first magnetic shield and the second magnetic shield are configured to shield the magnetic field detection element from an external magnetic field
Data Source
AI summary
A current sensor, which is configured to individually detect a current flowing in each of at least two current paths, includes at least two phases. Each phase includes a magnetic field detection element and a pair of first magnetic shield and second magnetic shield. The magnetic field detection element is disposed to face one of the current paths. The magnetic field detection element is configured to detect a magnetic field generated from the one of the current paths and to convert the detected magnetic field into an electric signal. The first magnetic shield and the second magnetic shield are disposed to face each other with the current path and the magnetic field detection element interposed between the first magnetic shield and the second magnetic shield. The first magnetic shield and the second magnetic shield are configured to shield the magnetic field detection element from an external magnetic field.