Magnetic Sensor Calibration Using Test Field Generator
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Solution Overview
Problem
Magnetic sensors, such as magnetoresistive (MR) sensors, face challenges with sensitivity variation due to external magnetic fields and temperature, and conventional housing structures often fail to fit in tight or constrained areas, making precise current measurements difficult.
Innovation Solution
The use of a test Magnetic Field Generator (MFG) and a test MFG driver to calibrate magnetic sensors by generating known magnetic fields, adjusting the bias signal to compensate for sensitivity variations, and employing flexible housing and circuit boards to accommodate sensors in constrained spaces.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Volume of moving object
If conventional housing structures are used for magnetic sensors, then manufacturing and assembly are simplified, but the sensors cannot fit in tight or constrained areas
Solution Approach 1:
The housing is divided into a first portion and a second portion that can be assembled together, allowing the sensor to fit in constrained areas while maintaining manufacturing simplicity through modular construction
Solution Approach 2:
The magnetic sensor is received within the housing structure, with the sensor body nested inside the housing portions, enabling compact integration in tight spaces
2Measurement precision
If magnetic sensors are used for current measurement, then contactless measurement is achieved, but sensitivity variation occurs due to external magnetic fields and temperature
Solution Approach 1:
A test magnetic field generator is used to apply a known magnetic field to the sensor before actual measurement, enabling preliminary calibration that compensates for sensitivity variations due to temperature and external fields
Solution Approach 2:
The bias signal applied to the magnetic sensor is adjusted based on calibration data obtained from the test magnetic field generator, compensating for sensitivity variations caused by temperature and external magnetic fields
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 accurate and reliable current measurements by stabilizing sensor sensitivity across varying conditions and enabling measurements in tight spaces, improving the operational range and reliability of magnetic sensors.
Implementation Method 1
a test Magnetic Field Generator (MFG) and a test MFG driver to calibrate magnetic sensors by generating known magnetic fields
Implementation Method 2
Magnetic sensors, such as magnetoresistive (MR) sensors, can be used for magnetic field sensing
Data Source
AI summary
A calibration apparatus for calibrating a magnetic sensor configured to generate an output signal indicative of magnetic field strength when a bias signal is applied to it is disclosed. The apparatus includes a test magnetic field generator (MFG) to generate magnetic fields of known magnitude, and further includes a processor to control the MFG to generate a known magnetic field, control the sensor to generate a test output signal when the MFG generates the known magnetic field and a known bias signal is applied to the sensor, and determine how to change the bias signal based on a deviation of the measured test output signal from an expected output signal. Using a test MFG that produces known magnetic fields when known bias signals are applied to sensors allows evaluating and compensating for changes in sensitivity of the sensors by accordingly changing bias signals applied to the sensors.