Electricity Meter Leading Power Factor Magnetic Field Detection
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Solution Overview
Problem
Existing electricity meters are prone to inaccuracies due to external magnetic fields, which current solutions attempt to mitigate through additional equipment or shielding, but these approaches are costly and not easily retrofittable to existing meters.
Innovation Solution
Incorporating a sensor circuit and control circuit within the meter to detect leading power factors, which serve as an indicator of potential magnetic field interference, allowing for the detection and flagging of possible magnetic field errors without the need for separate magnetic sensors or shields.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If magnetic shielding structures are added to reduce magnetic field impact, then meter reliability is improved, but device complexity and manufacturing cost increase
Solution Approach 1:
The patent replaces the mechanical/physical magnetic shielding system with an electronic detection and correction system. Instead of using ferromagnetic shielding materials to physically block magnetic fields, the invention uses sensors to detect magnetic field interference and electronic circuits to calculate and apply correction factors to the metering measurements, thereby eliminating the need for complex shielding structures.
Solution Approach 2:
The patent introduces magnetic field sensors as intermediary devices that detect the presence and strength of external magnetic fields. These sensors act as mediators between the magnetic field interference and the metering system, providing information that enables the control circuit to apply appropriate corrections without requiring physical shielding.
2Reliability
If magnetic field sensors are added to detect and flag excess magnetic fields, then meter reliability is improved, but device complexity and equipment cost increase
Solution Approach 1:
The patent replaces complex magnetic field sensing and flagging systems with a simplified detection and correction approach. Instead of using separate magnetic field sensors that require additional circuitry and processing, the invention integrates magnetic field detection into the existing current sensing system and uses the control circuit to perform both detection and correction functions.
Solution Approach 2:
The patent makes the control circuit multi-functional by enabling it to perform both normal metering calculations and magnetic field interference detection and correction. The same control circuit that processes voltage and current signals for energy measurement is also used to detect magnetic field effects and apply corrections, eliminating the need for dedicated magnetic field sensing equipment.
3Reliability
If magnetic shielding or sensor equipment is added, then meter reliability is improved, but ease of manufacture and retrofitting deteriorate
Solution Approach 1:
The patent replaces physical modifications such as adding shielding structures or sensor equipment with software-based solutions. The magnetic field correction is implemented through firmware or software algorithms that can be loaded into existing meter processors, allowing retrofitted meters to gain magnetic field compensation capability without physical hardware modifications.
Solution Approach 2:
The patent implements magnetic field correction by changing operational parameters through software rather than physical modifications. The control circuit adjusts measurement parameters and applies correction factors based on detected magnetic field conditions, enabling retrofitted meters to adapt to magnetic field interference through parameter adjustments rather than hardware changes.
Data Source
AI summary
An electricity meter includes a sensor circuit, a measurement circuit, a leading PF detection circuit and a control circuit. The sensor circuit is operably connected to detect voltage and current provided to a load, and generates corresponding voltage and current measurement signals. The measurement circuit is configured to generate energy consumption information based on the voltage and current measurement signals. The leading PF detection circuit is configured to generate a first value representative of a phase difference of the current measurement signal with respect to the voltage measurement signal, and to generate a leading PF detection signal responsive to determining that the first value corresponds to a leading power factor that leads unity power factor by more than a predetermined threshold. The control circuit stores an indication in memory responsive at least in part to the leading PF detection signal.