Contactless Power Sensing via Magnetic Field Calibration
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Solution Overview
Problem
Existing methods for whole-home power consumption monitoring are challenging due to the need for professional installation, limited accuracy in measuring real power usage, and inability to account for phase information between voltage and current waveforms, especially for inductive loads like CFLs and HVAC systems, which are common in modern homes.
Innovation Solution
A contactless power consumption sensing system using magnetic field sensors attached to a circuit breaker panel, coupled with a calibration device and processing modules that automatically calibrate to determine the transfer function and infer real power usage without direct electrical or physical connection to the power infrastructure, leveraging a neural network model to account for non-linearities and interference from branch circuits.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If current transformers are installed inside the breaker panel, then power consumption monitoring accuracy is improved, but installation complexity and safety requirements increase
Solution Approach 1:
The patent uses magnetic field sensors as an intermediary device to measure power consumption without direct electrical connection. The sensors detect magnetic fields generated by current flow through the breaker panel, allowing accurate monitoring while avoiding the safety hazards and installation complexity of traditional current transformers that require electrical contact.
Solution Approach 2:
The patent replaces the mechanical/electrical contact-based current transformer system with a magnetic field-based sensing system. This substitution eliminates the need for physical connection to electrical circuits, thereby reducing installation complexity and safety requirements while maintaining measurement accuracy.
2Device complexity
If traditional magnetic field sensors are used without calibration, then device complexity is reduced, but measurement precision deteriorates due to non-linearities and interference
Solution Approach 1:
The patent implements a calibration process that performs preliminary measurements and computations to establish transfer functions before actual power monitoring begins. The system measures magnetic field signals under known conditions, computes calibration factors, and stores these for use during normal operation, thereby improving accuracy without adding significant complexity to the ongoing monitoring function.
Solution Approach 2:
The patent uses feedback from measured magnetic field signals to continuously refine power consumption calculations. The system compares sensed signals with calibration data and adjusts measurements accordingly, compensating for non-linearities and interference from branch circuits. This feedback mechanism improves measurement precision while maintaining relatively simple device architecture.
3Ease of operation
If contactless sensing is implemented, then ease of installation is improved, but measurement precision may worsen due to distance and interference factors
Solution Approach 1:
The patent measures magnetic field signals in multiple dimensions by using multiple sensors positioned at different locations on the breaker panel. This multi-dimensional approach allows the system to capture the complete magnetic field signature and compensate for distance and positioning variations, maintaining measurement accuracy while preserving the ease of contactless installation.
Solution Approach 2:
The patent uses magnetic field sensors as an intermediary that can detect current through the metal panel without direct contact. The magnetic field penetrates the panel material, allowing the sensors to measure current waveforms accurately from the exterior of the breaker panel, thereby maintaining both ease of installation and measurement precision.
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 accurate, real-time monitoring of whole-home power consumption without professional installation, capable of predicting absolute current waveforms and phase angles, thus providing precise real power usage data across a wide range of loads and reducing installation complexity.
Implementation Method 1
magnetic field sensors configured to measure a magnetic flux generated by at least part of the one or more electrical power supply lines and generate a plurality of output signals representing the magnetic flux measured by the magnetic field sensors
Data Source
AI summary
A system for sensing electrical power usage in an electrical power infrastructure of a structure. The system can include a sensing device configured to be attached to a panel of the circuit breaker box overlying at least part of the one or more main electrical power supply lines. The system also can include a calibration device configured to be electrically coupled to the electrical power infrastructure of the structure. The system further can include one or more processing modules configured to receive one or more output signals from the sensing device. The sensing device can be devoid of being electrically or physically coupled to the one or more main electrical power supply lines or the electrical power infrastructure when the sensing device is attached to the panel. Other embodiments are provided.