Auto-calibrating Current Sensor IC Using Electromagnetic Model
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Solution Overview
Problem
Conventional current sensors are susceptible to significant measurement errors due to slight misplacement or misalignment of magnetic field sensing elements, requiring manual calibration for accurate current measurement.
Innovation Solution
An auto-calibrating current sensor integrated circuit (IC) that includes multiple magnetic field sensing elements, an electromagnetic model, and a processor to measure magnetic fields, calculate coupling factors, and determine the sensor's position relative to a conductor, enabling self-calibration.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If manual calibration is performed to achieve accurate current measurement, then measurement precision is improved, but device complexity and time consumption increase
Solution Approach 1:
The current sensor performs self-calibration by automatically determining its position relative to the conductor using multiple magnetic field sensing elements and an electromagnetic model. The processor calculates coupling factors and solves for sensor position and current without external intervention, making the system self-sufficient and eliminating manual calibration requirements.
Solution Approach 2:
The system pre-stores an electromagnetic model that describes the relationship between sensor position and magnetic field coupling factors. During operation, this pre-established model is used to rapidly calculate position and current measurements, avoiding the need for time-consuming manual calibration procedures each time the sensor is deployed.
2Measurement precision
If manual calibration is performed to achieve accurate current measurement, then measurement precision is improved, but loss of time increases
Solution Approach 1:
The sensor automatically performs calibration by measuring magnetic fields from multiple sensing elements and computing its position using the stored electromagnetic model. This self-calibration process occurs rapidly during normal operation without requiring external calibration equipment or technician intervention, eliminating time loss associated with manual calibration.
Solution Approach 2:
The electromagnetic model is pre-computed and stored in the sensor before deployment. When the sensor is installed, it immediately uses this pre-prepared model to calculate its position and begin accurate measurements, eliminating the time required for on-site manual calibration procedures.
3Adaptability or versatility
If multiple magnetic field sensing elements are used to enable auto-calibration, then adaptability is improved, but device complexity increases
Solution Approach 1:
The sensor divides the magnetic field measurement task across multiple discrete sensing elements positioned at different locations. Each element measures the magnetic field from its unique position, providing segmented data that the processor combines with the electromagnetic model to calculate overall sensor position and current, enabling auto-calibration through distributed measurement.
Solution Approach 2:
The multiple magnetic field sensing elements serve dual purposes: they individually measure local magnetic field strengths and collectively provide positional information for auto-calibration. This multi-functionality allows the same hardware components to perform both measurement and calibration functions without requiring separate dedicated elements.
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 auto-calibrating current sensor IC achieves accurate current measurements by compensating for misplacement errors, eliminating the need for manual calibration and ensuring reliable operation in applications such as electric vehicles.
Implementation Method 1
a plurality of magnetic field sensing elements disposed at different locations within the integrated circuit, respectively, and configured to measure a magnetic field produced by a current carried by the conductor
Data Source
AI summary
Auto-calibrating current sensor integrated circuits (ICs) are configured for mounting at a position relative to a conductor. The auto-calibrating current sensor ICs can include a plurality of magnetic field sensing elements disposed at different locations within the integrated circuit, respectively, and can be configured to measure a magnetic field produced by a current carried by the conductor. The auto-calibrating sensors can include an electromagnetic model of the IC and the conductor. The model can be operative to determine a magnetic field at points in space due to a given current in the conductor at a known location of the conductor from the IC, and also the inverse situation of determining an unknown current and/or location of the conductor based on measurements of a magnetic field at known locations in space due to an unknown current in the conductor. Related auto-calibration methods are also described.