Polarization Insensitive Optical Current Sensor with Active Temperature Compensation
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Solution Overview
Problem
Existing current sensors face limitations due to electromagnetic interference (EMI) and require electrical power, making them unsuitable for high-voltage applications and prone to current saturation, with challenges in accuracy and dynamic range due to temperature dependence and magnetic field interferences.
Innovation Solution
The use of optical sensing technology with Faraday effects in optical dielectric materials, allowing for remote measurement of electric currents and temperatures via light transmission, eliminating the need for electrical power at the sensor head and providing immunity to EMI, and integrating current and temperature sensing using wavelength division multiplexing.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If electronic circuits are used for current sensing, then current measurement can be achieved, but the sensor is adversely affected by electromagnetic interference (EMI) and requires electrical power
Solution Approach 1:
The patent replaces electronic circuitry with optical components and photonic sensors to perform current measurement. The sensor head uses optical waveguides and photodetectors instead of electronic circuits, transmitting signals through optical fibers to a remote base station, thereby eliminating susceptibility to electromagnetic interference while maintaining measurement capability
Solution Approach 2:
The patent introduces optical fibers as an intermediary medium to transmit measurement data from the sensor head to the base station. This optical intermediary isolates the sensing element from electromagnetic fields while enabling remote data transmission, solving both the EMI immunity and power supply problems
2Measurement precision
If sensor head is located at the measurement location, then accurate current measurement is achieved, but installation is limited in high-voltage applications
Solution Approach 1:
The patent divides the sensing system into two separate components: a sensor head positioned at the measurement location that contains only passive optical elements, and a remote base station that contains electronic processing equipment. This segmentation allows the sensor head to be installed in high-voltage environments without risking damage to electronic components, while still achieving accurate measurements
3Reliability
If optical sensing technology is used, then immunity to EMI and remote sensing are achieved, but temperature dependence affects measurement accuracy
Solution Approach 1:
The patent incorporates temperature sensors that continuously monitor the environmental conditions at the sensor head location. The measured temperature data is transmitted to the base station and used to compensate for temperature-induced variations in the optical properties of the waveguide and photodetector, thereby maintaining measurement accuracy across different temperature conditions
Solution Approach 2:
The patent uses temperature compensation techniques that adjust measurement parameters based on detected temperature variations. By measuring the temperature and applying correction factors to the optical measurement data, the system maintains accuracy despite changes in environmental temperature
4Measurement precision
If polarization-sensitive optical components are used, then sensitivity is improved, but the sensor becomes sensitive to polarization changes affecting measurement stability
Solution Approach 1:
The patent employs polarization-maintaining optical components and designs the optical path to preserve a consistent polarization state throughout the measurement process. By ensuring homogeneous polarization conditions and using components that maintain rather than alter polarization, the system achieves both high sensitivity and measurement stability without being affected by polarization variations
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 solution enables accurate, long-distance remote sensing with immunity to EMI, reducing installation costs and enhancing environmental stability, while maintaining high sensitivity and linearity, and compensating for temperature effects, thus improving the dynamic range and accuracy of current and temperature measurements.
Implementation Method 1
the sensing media are optical dielectric materials exhibiting Faraday effects
Implementation Method 2
temperature compensation for drift in the polarization state of the input light
Data Source
AI summary
This patent document discloses techniques and devices for sensing or measuring electric currents and/or temperature based on photonic sensing techniques. The optical sensors for sensing the current or temperature can be configured as a polarization-insensitive optical sensor in either an optical transmissive configuration or an optical reflective configuration.