Circuit Breaker Panel Current Sensing With Vector Magnetometers
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Solution Overview
Problem
Existing current measurement technologies face challenges such as voltage drop, permanent magnetization of cores, interference, and high costs when measuring current in circuit breaker panels, particularly in non-invasive and long-term monitoring applications.
Innovation Solution
A vector magnetometer-based system using 3-sensor magnetometers with adhesive attachment, positioned over and adjacent to circuit breakers, to detect magnetic fields and estimate current without direct contact, with data processing to eliminate interference and calibrate for accuracy.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If an ammeter is placed in series with a circuit to measure current, then current measurement is achieved, but voltage drop is introduced into the circuit
Solution Approach 1:
The patent uses magnetic field interaction as an intermediary between the measurement system and the circuit. A magnetometer detects the magnetic field generated by current flow in the circuit breaker, allowing current measurement without direct electrical contact or series insertion, thereby eliminating voltage drop while maintaining measurement capability
Solution Approach 2:
The patent replaces the traditional electrical/series connection method with a magnetic field-based detection system. Instead of inserting an ammeter into the electrical circuit, the system uses magnetometers to detect the magnetic field produced by current flow, substituting mechanical/electrical contact with field-based sensing
2Measurement precision
If current clamps with iron cores are used to measure AC current non-invasively, then current measurement is achieved, but permanent magnetization distorts future measurements
Solution Approach 1:
The patent employs inexpensive, disposable magnetometer sensors that do not suffer from permanent magnetization issues. These sensors can be easily replaced if needed, and their low cost allows for multiple units to be used throughout the system, eliminating the reliability problem associated with iron core saturation
Solution Approach 2:
The patent changes the material properties and operating parameters of the sensing system by using magnetometers with different magnetic characteristics than traditional iron core clamps. This parameter change eliminates the permanent magnetization effect while maintaining the ability to measure AC current accurately
3Reliability
If Rogowski coils are used to avoid permanent magnetization, then measurement reliability is improved, but positioning requirements become more stringent
Solution Approach 1:
The patent implements automatic calibration and compensation features that allow the system to self-correct for positioning errors and environmental factors. The microcontroller processes sensor data with built-in algorithms that compensate for misalignment and interference, eliminating the need for precise manual positioning while maintaining measurement reliability
Solution Approach 2:
The system uses feedback mechanisms where the microcontroller continuously processes magnetometer data, compares it against expected values, and applies corrections for positioning errors and interference. This feedback loop maintains accurate measurements even when sensors are not perfectly positioned
4Measurement precision
If inductive current measurement methods are used, then non-invasive measurement is achieved, but interference from other sources affects measurement accuracy
Solution Approach 1:
The patent extracts and separates the signal of interest from interfering signals through differential measurement techniques. By using multiple magnetometers and comparing their readings, the system isolates the magnetic field generated by the target circuit breaker from other sources of magnetic interference in the panel
Solution Approach 2:
The patent uses magnetic field interaction as an intermediary that is specific to the target circuit breaker's current flow. By positioning sensors to detect only the magnetic field from the specific breaker being measured and using differential techniques, the system filters out other magnetic interference sources
5Reliability
If commercial current clamps with low-pass filters are used to mitigate interference, then measurement reliability is improved, but cost increases
Solution Approach 1:
The patent uses the microcontroller's built-in processing capabilities to perform digital filtering and interference mitigation instead of requiring expensive analog low-pass filter hardware. The system leverages software algorithms to achieve the same reliability benefits at lower cost
Solution Approach 2:
The patent changes from hardware-based filtering (analog low-pass filters) to software-based filtering (digital signal processing). This parameter change in the filtering approach maintains measurement reliability while significantly reducing system cost
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
Enables efficient, cost-effective, and accurate measurement of current magnitudes in circuit breaker panels with simplified calibration, reducing interference and providing real-time data for energy management.
Implementation Method 1
vector magnetometer based detection of electric currents in a nearby wire
Data Source
AI summary
A system for detecting current magnitudes in a circuit breaker panel includes multiple 3-sensor magnometers placed over the main breaker and branch circuits in the circuit breaker enclosure. The sensors communicate with a local processing node, which analyzes the raw data to compensate for external and local interference, and provides an estimated current measurement. The estimated current measurement is then communicated back to a user system which can then use the information to better manage current input and output.