Annular Current Sensor Core Dimension Optimization
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Solution Overview
Problem
Current sensors for low-voltage circuits face challenges in accurately measuring current levels without an external power supply, requiring high nominal current capability, low starting current operation, and compact, cost-effective designs, while existing solutions suffer from limited service life, high cost, and size constraints.
Innovation Solution
A current sensor utilizing an annular magnetic core with a secondary winding that functions both as a current transformer for measurement and energy supply, optimizing core dimensions to achieve efficient energy production and current determination, allowing for a compact and wireless data transmission.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Use of energy by moving object
If an internal energy store such as a battery is used for supplying energy, then the sensor can operate without external power supply, but the service life and operating temperature are limited
Solution Approach 1:
The current transformer serves dual functions: it measures current and generates power for the sensor's electronics. The secondary winding induces voltage that powers the measurement circuitry, eliminating the need for separate power sources like batteries and thereby extending service life.
Solution Approach 2:
The magnetic core and windings are designed to perform both measurement and energy generation functions. The same current transformer structure that measures current also generates electrical energy to power the sensor, reducing component count and improving reliability.
2Measurement precision
If energy production with a primary current flow using a converted current and a separate transformer is used, then the sensor can measure current accurately, but the device becomes expensive and large
Solution Approach 1:
The patent combines the current measurement function and power generation function into a single integrated current transformer. The secondary winding serves both to provide measurement current and to generate power for the sensor electronics, eliminating the need for separate transformers and reducing overall device size.
3Measurement precision
If the sensor is designed to operate at very low starting current, then the sensor can measure low current levels accurately, but the energy available for measurement is limited
Solution Approach 1:
The sensor electronics are designed to operate efficiently at low power levels, with the measurement circuitry optimized to function accurately even when powered by the limited energy generated from low current measurements. The system adjusts its operational parameters to maintain measurement precision across the full current range.
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 solution enables a compact, accurate, and cost-effective current sensor that can operate across a wide range of current levels, including low starting currents, with improved energy efficiency and reduced heat dissipation, addressing the limitations of existing technologies.
Implementation Method 1
a current transformer which has a magnetic core and is used both to measure the level of the current of the conductor and to supply energy to the current sensor
Data Source
AI summary
A current sensor is for determining the level of the current of a conductor of a low-voltage circuit. In an embodiment, it includes a current transformer including a magnetic core. The magnetic core is an annular core having a core inner diameter, a middle diameter and a core outer diameter. The annular core is wound with a secondary winding, including an inner opening with an inner diameter and an outer circumference with an outer diameter. The secondary winding supplies the circuit with electrical energy. The wound annular core is configured such that the difference between the middle diameter as the minuend and the inner diameter as the subtrahend is 0.5 to 0.6 times smaller than the difference between the outer diameter as the minuend and the inner diameter as the subtrahend, to achieve an optimum for supplying energy and determining the level of the current in connection with the circuit.