ODMR Magnetic Sensor with Dual Diamond Elements for External Field Cancellation
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Solution Overview
Problem
Magnetic sensors face challenges in accurately eliminating external magnetic fields due to non-uniform characteristics of diamond elements and temperature variations, especially when measuring currents in electric vehicle bus bars, leading to inaccurate magnetic field detection.
Innovation Solution
A sensor system comprising two magnetic sensors with diamond elements having NV centers, an optical system for excitation light, and a processor to calculate the difference between magnetic fields detected by each sensor, effectively eliminating external magnetic fields and accounting for temperature variations.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a pair of diamond elements are disposed close to each other to detect magnetic fields, then the ability to eliminate external magnetic fields is improved, but the requirement for uniform characteristics of the diamond elements becomes more stringent
Solution Approach 1:
The patent introduces a feedback mechanism where the system detects temperature variations and adjusts operations accordingly. The processor calculates temperature based on the difference in magnetic field signals from the two diamond elements and uses this information to compensate for temperature-induced drift, thereby maintaining measurement precision without requiring extremely uniform diamond elements.
Solution Approach 2:
The patent changes the operating parameters by introducing temperature compensation. The system monitors temperature changes and adjusts the measurement calculations to account for thermal effects on the diamond elements' magnetic susceptibility, allowing the sensors to maintain accuracy despite variations in element characteristics.
2Measurement precision
If magnetic sensors are used to measure current in bus bars with large current flow, then the ability to detect magnetic fields is improved, but temperature differences between sensor locations affect measurement accuracy
Solution Approach 1:
The system uses the temperature difference information as feedback to compensate for its effects on the magnetic field measurements. The processor calculates temperature based on the signal difference and uses this feedback to adjust the magnetic field calculations, thereby eliminating temperature-induced measurement errors.
Solution Approach 2:
The patent converts the harmful temperature difference effect into a useful measurement. By calculating the temperature from the difference in magnetic field signals (which also contains temperature information), the system turns the temperature variation from a source of error into a parameter that can be used for compensation and environmental monitoring.
3Measurement precision
If diamond elements with NV centers are used for magnetic field detection, then the sensitivity to magnetic fields is improved, but the elements are affected by external magnetic fields and temperature
Solution Approach 1:
The patent segments the measurement into two independent parts: one sensor measures the sum of the target magnetic field and external magnetic field, while the other measures the external magnetic field alone. By separating these measurements, the system can isolate and eliminate the external magnetic field effect from the final result.
Solution Approach 2:
The patent uses the temperature effect on NV centers, which normally degrades performance, as a useful indicator to monitor and compensate for environmental conditions. The temperature information derived from the magnetic field difference is used to correct measurement drift, turning a harmful effect into a compensatory mechanism.
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
The system enables precise detection of magnetic fields by suppressing external magnetic field effects and temperature-related variations, improving measurement accuracy for current measurements in electric vehicle bus bars.
Implementation Method 1
an optical sensor configured to detect an intensity of a fluorescence generated by the element
Implementation Method 2
an antenna configured to radiate a microwave magnetic field to the element
Implementation Method 3
A magnetic sensor is known for measuring a magnetic field by utilizing a principle of Optically Detected Magnetic Resonance (ODMR) using diamond elements having NV centers
Data Source
AI summary
A sensor includes two magnetic sensors detecting a magnetic field around an object, and outputting at least one of a magnetic field signal and a temperature signal, an optical system emitting the excitation light to the two magnetic sensors, and a processor calculating a difference between a magnetic fields corresponding to the magnetic field signal detected by the two magnetic sensors, wherein each of the magnetic sensors includes an element disposed around the object and having color centers, an antenna radiating a microwave magnetic field to the element, an optical sensor detecting an intensity of a fluorescence generated by the element, and outputting an intensity signal, and a controller calculating at least one of a magnetic field and temperature around the measurement object, and output at least one of a magnetic field signal indicating the calculated magnetic field and a temperature signal indicating the calculated temperature to the processor.