Current Sensor with Switched Feedback Coils for Wide Range Accuracy
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Current electrical current sensors face challenges in achieving high accuracy over a wide measuring range due to limitations in both magnetic proportional and magnetic balance sensors, which either sacrifice resolution for large currents or struggle with small currents, and existing solutions require multiple sensors, complicating manufacturing and increasing costs.
Innovation Solution
A current sensor design featuring a magnetic detection element and multiple coils connected in series, with a switch circuit to control the number of coils for feedback current, allowing for adjustable magnetic field cancellation and enabling high accuracy across a wide range while reducing power consumption and saving space.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If the number of turns of the feedback coil is fixed to measure large current, then the measuring range is extended, but the resolution for small current measurement is reduced
Solution Approach 1:
The feedback coil system uses multiple coils with different numbers of turns that can be dynamically switched based on the current measurement range. The switch circuit selects appropriate coils (first feedback coil, second feedback coil, or third feedback coil) to provide optimal resolution for small currents while maintaining the ability to measure large currents, thus resolving the contradiction between fixed coil turns and variable measurement requirements
Solution Approach 2:
The feedback coil is divided into multiple separate coils (first, second, and third feedback coils) with different numbers of turns. This segmentation allows the system to select the appropriate coil for each measurement scenario, enabling high resolution for small currents when needed while maintaining extended measuring range capability through switching between different coil configurations
2Adaptability or versatility
If the measuring range is extended to measure large current, then the adaptability is improved, but the measurement precision for small current is reduced
Solution Approach 1:
The system dynamically adjusts the feedback coil configuration based on the measured current magnitude. The switch circuit responds to current levels and selects the appropriate coil (first for large current, second or third for small current), enabling the measuring range to be extended while maintaining measurement precision through adaptive switching
Solution Approach 2:
The system changes the effective number of turns parameter of the feedback coil by switching between different coils with different turn counts. This parameter change allows the system to optimize the feedback magnetic field strength for each measurement scenario, maintaining measurement precision across the extended measuring range
3Measurement precision
If two different types of current sensors are arranged to measure different current ranges, then the measurement precision over wide range is improved, but the device complexity and manufacturing cost increase
Solution Approach 1:
The patent merges multiple feedback coil functions into a single magnetic balance current sensor structure. Instead of using separate sensors, the system combines first, second, and third feedback coils with different turn counts within one sensor housing, sharing common components such as the magnetic detection element, core, and circuitry, thus reducing device complexity while maintaining measurement precision
Solution Approach 2:
The single magnetic balance current sensor is designed to perform multiple measurement functions by switching between different feedback coils. The same sensor structure can measure both large currents (using first feedback coil) and small currents (using second or third feedback coils), eliminating the need for multiple specialized sensors and reducing overall system 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
This design allows for precise current measurement over a wide range with reduced power consumption and space requirements, effectively addressing the limitations of existing sensors by dynamically adjusting the coil configuration based on the measured current.
Implementation Method 1
a magnetic detection element whose characteristics are changed due to an inductive magnetic field from a current to be measured
Implementation Method 2
a plurality of coils that are connected in series with each other and which are arranged in the vicinity of the magnetic detection element, and generates a canceling magnetic field for canceling the inductive magnetic field by a feedback current flowing in the coils
Data Source
AI summary
An electrical current sensor includes a magnetic detection element whose characteristics are changed by an inductive magnetic field from a current to be measured, a plurality of coils that are connected in series with each other and which are arranged in the vicinity of the magnetic detection element, and generates a canceling magnetic field for canceling the inductive magnetic field by a feedback current flowing in the coils, and a switch circuit that selects a coil electrically connected with an input terminal and/or an output terminal of the feedback current from the plurality of coils, and controls a coil for allowing the feedback current to flow.