Non-contact Current Sensor Compensation for Mounting Variation
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Solution Overview
Problem
Non-contact current sensors on two-wire power cables suffer from measurement bias due to improper mounting positions, leading to unstable and often erroneous readings, which are not effectively compensated by existing technologies.
Innovation Solution
A compensating apparatus using a pair of measurement devices and calculation algorithms to estimate human and manufacturing variations, employing magnetic sensors to derive the current and displacement values, forming simultaneous equations to accurately compute the current regardless of mounting position through 2D coupling computations.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If non-contact current sensor is used on two-wire power cable, then direct contact measurement is avoided and multi-core cable compatibility is improved, but measurement bias occurs due to improper mounting position
Solution Approach 1:
The patent implements a feedback mechanism by measuring the actual mounting position (distance and horizontal displacement) and using this information to correct the current measurement. The system continuously monitors the sensor position relative to the power cable and adjusts the measurement results accordingly, eliminating the measurement bias that would otherwise occur due to improper mounting positions.
Solution Approach 2:
The patent changes the measurement parameters by introducing position-dependent correction factors. Instead of using a fixed measurement model, the system dynamically adjusts the measurement parameters based on the actual mounting position, including the distance from the sensor to the cable and the horizontal displacement, thereby compensating for position-induced measurement errors.
2Volume of moving object
If Hall element is used for non-contact measurement, then volume is reduced and direct contact is avoided, but distance between sensor and power cable becomes critical
Solution Approach 1:
The patent enables the measurement system to self-correct for mounting position errors by automatically measuring its own position relative to the power cable and applying appropriate corrections. The system measures the distance and horizontal displacement itself and uses this self-acquired information to compensate for any mounting inaccuracies, eliminating the need for precise manual positioning.
Solution Approach 2:
The patent performs preliminary measurement of the mounting position (distance and horizontal displacement) before conducting the actual current measurement. By establishing the position parameters in advance, the system can pre-calculate the necessary correction factors and apply them during the measurement process, ensuring accurate results regardless of mounting variations.
3Device complexity
If single measurement device is used, then device complexity is reduced, but measurement bias due to mounting variation cannot be compensated
Solution Approach 1:
The patent segments the measurement function into multiple independent components: one measurement device for detecting the magnetic field signal, a separate position measurement device for detecting distance and horizontal displacement, and a processing unit for integrating these measurements and applying corrections. This segmentation allows each component to perform its specific function optimally while working together to achieve accurate current measurement despite mounting variations.
Solution Approach 2:
The patent introduces position measurement as an intermediary element between the current sensor and the final measurement result. By measuring the mounting position (distance and horizontal displacement) as an intermediate parameter, the system can use this information to correct the current measurement, acting as a mediator that bridges the gap between the sensor output and the accurate current value.
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 significantly reduces measurement bias, achieving stable and accurate current detection across various mounting positions, thereby enhancing the reliability of non-contact current sensors on two-wire power cables.
Implementation Method 1
According to the Ampere principle, when an electric current flows through a conductive object, a surrounding magnetic field would be induced. The magnitude of the induced magnetic field is proportional to the current in the conductive object, but is inversely proportional to the spacing in between.
Implementation Method 2
According to the Faraday principle, the induced voltage of the coil can be computed as V = N * dφ/dt, in which the N is the number of the coil of the lead, the A is the area circulated by the coil, and the φ is the effective flux.
Data Source
AI summary
A compensating apparatus for installing variation of a non-contact current sensor on a two-wire power cable includes a non-contact current sensor, a sensing element characteristic measuring unit and a non-contact current measurement module. The non-contact current sensor mounted top to the two-wire power cable further has a first current sensor, a second current sensor, and a third current sensor. The sensing element characteristic measuring unit is to construct a space characteristic measuring database for the non-contact current sensor respective to the two-wire power cable. The non-contact current measurement module is to pair the space characteristic measuring database so as to compute and further output a measured value of the current I in the two-wire power cable.