Fluxgate Current Sensor Shielding for High-Current Linearity
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Semiconductor fluxgate sensors face limitations in measuring high currents due to magnetic core saturation, which restricts the linear range of current measurements to less than 100 A, limiting their effectiveness in accurately sensing electrical currents.
Innovation Solution
Incorporating a discrete ferromagnetic plate as a magnetic shield between the semiconductor fluxgate sensor and the current-carrying conductor, which extends the linear range of current measurements by compensating the magnetic field and reducing saturation effects, allowing for reliable measurements up to 300 A or more.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a semiconductor fluxgate sensor is used to measure current, then measurement precision is improved, but the measurement range is limited due to magnetic core saturation
Solution Approach 1:
A discrete ferromagnetic plate is introduced as an intermediary element between the current-carrying conductor and the semiconductor fluxgate sensor. This plate acts as a magnetic shield that modifies the magnetic field distribution, allowing the sensor to accurately measure currents up to 300A or more without saturation, thereby extending the measurement range while maintaining precision
Solution Approach 2:
The magnetic field parameters are changed by introducing the ferromagnetic plate, which alters the magnetic flux distribution and prevents core saturation. This parameter modification enables the sensor to operate linearly over a wider current range, transforming the limited measurement capability into an extended measurement range
2Adaptability or versatility
If the measurement range is extended to high currents, then adaptability is improved, but measurement precision deteriorates due to magnetic core saturation
Solution Approach 1:
The discrete ferromagnetic plate serves as a magnetic shield intermediary that prevents direct interaction between the high-current magnetic field and the sensor's magnetic core. This intermediary structure maintains the linear relationship between magnetization and current even at high current levels, preserving measurement precision across an extended range
3Measurement precision
If a magnetic shield is added to extend measurement range, then measurement precision is improved, but device complexity increases
Solution Approach 1:
A discrete ferromagnetic plate is positioned between the conductor and sensor to shield the magnetic field. This simple plate structure improves measurement precision by preventing core saturation while adding minimal structural complexity compared to more complex magnetic shielding arrangements
Solution Approach 2:
The ferromagnetic plate provides localized magnetic shielding only in the critical region between the conductor and sensor, rather than requiring complete shielding of the entire device. This localized approach maintains measurement precision while minimizing the added 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 use of a discrete ferromagnetic plate as a magnetic shield enhances the linear relationship between magnetization and current, enabling reliable and accurate current sensing beyond the initial limitations, effectively extending the measurement range of semiconductor fluxgate sensors.
Implementation Method 1
at least one elongated bar of a first ferromagnetic material magnetized by the first magnetic field
Implementation Method 2
a first coil wrapped around the at least one elongated bar configured to sense the magnetization of the at least one elongated bar
Implementation Method 3
an electronic driver configured to create a second electrical current flowing through a second coil wrapped around the at least one elongated bar, the second electrical current configured to generate a second magnetic field to compensate for the magnetization of the at least one elongated bar
Implementation Method 4
a discrete plate of a second ferromagnetic material in the first clearance, the discrete plate being conformal with the first outer surface of the package
Data Source
AI summary
A current-sensing system includes a conductor for carrying a first electrical current generating a first magnetic field. A device, spaced from the conductor by a clearance, includes a semiconductor integrated circuit die in a package. The semiconductor integrated circuit die includes at least one elongated bar of a first ferromagnetic material magnetized by the first magnetic field; a sensor comprising a first coil wrapped around the at least one elongated bar to sense the bar's magnetization; and an electronic driver creating a second electrical current flowing through a second coil wrapped around the at least one elongated bar generating a second magnetic field to compensate the at least one bar's magnetization. The package has a first outer surface free of device terminals. A discrete plate of a second ferromagnetic material is positioned in the clearance and is conformal with the first outer surface of the package.