Self-Powered CT Current Sensor Calibration for Continuous Sampling
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Solution Overview
Problem
Conventional current sensor designs face challenges in miniaturization and high cost due to complex circuit designs and high power consumption, with intermittent sampling leading to inability to detect sudden current changes and low sampling precision.
Innovation Solution
A current sensor unit with a rectification module, power source conversion module, mode switching module, current sensor module, control module, and signal conditioning module, which converts AC current to pulsed DC current for continuous detection and efficient power management, allowing for precise sampling and reduced power consumption.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If an additional power source is used to supply power to electronic components, then the electronic components can operate stably, but the circuit design becomes complex and the current sensor cannot be miniaturized
Solution Approach 1:
The mutual inductor is designed to perform dual functions: current sensing and power supply. By extracting a portion of the magnetic energy from the mutual inductor's magnetic field, the system eliminates the need for separate power sources while maintaining stable power supply to electronic components, thereby reducing circuit complexity and enabling miniaturization
Solution Approach 2:
The patent merges the power supply function with the current sensing function by using the same mutual inductor for both purposes. The power extraction circuit taps into the magnetic energy already present in the mutual inductor, combining two functions into one component to simplify the overall circuit design
2Loss of energy
If time division multiplexing is used to supply power intermittently, then power consumption is reduced, but the current sensor cannot detect sudden current changes
Solution Approach 1:
The system uses periodic pulsed excitation to generate magnetic energy in the mutual inductor at a frequency higher than the sampling rate. This periodic energy generation allows the circuit to operate in a low-power state between pulses while maintaining the capability to detect sudden current changes, as the high-frequency pulsing ensures continuous energy availability for detection
Solution Approach 2:
The mutual inductor stores magnetic energy in advance during the pulsing periods, preparing energy reserves that can be quickly released when needed for detection. This preliminary energy storage allows the system to respond rapidly to sudden current changes without requiring continuous high-power operation
3Duration of action of stationary object
If continuous power supply is used, then the electronic components operate continuously, but the power consumption is high and sampling precision is low
Solution Approach 1:
Instead of continuous power supply, the system employs periodic pulsed excitation to generate magnetic energy in the mutual inductor. The energy storage capacitor maintains voltage between pulses, allowing continuous operation of electronic components while significantly reducing average power consumption compared to continuous excitation
Solution Approach 2:
The system maintains continuous useful action by using an energy storage capacitor that releases energy between excitation pulses. This ensures that electronic components receive continuous power supply for stable operation while the pulsed excitation method reduces overall power consumption and improves sampling precision
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
Enables continuous current detection, improves sampling precision, and reduces power consumption, effectively addressing the limitations of conventional designs by using pulsed DC current for efficient energy storage and release.
Implementation Method 1
a mutual inductor, configured to generate magnetic energy through pulsed excitation
Implementation Method 2
A current sensor unit with a rectification module, power source conversion module, mode switching module, current sensor module, control module, and signal conditioning module, which converts AC current to pulsed DC current
Data Source
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AI summary
The embodiments of the present invention disclose a current sensor unit and a current detection circuit. The current sensor unit comprises: a rectification module, which converts an AC current to a pulsed DC current; a power source conversion module containing an energy storage element, which stores energy for the energy storage element on the basis of the pulsed DC current during operation in a charging mode and generates a power supply current; a mode switching module, which is bypassed by the power source conversion module during operation in the charging mode, and bypasses the power source conversion module during operation in an energy release mode; a current sensor module, which detects a pulsed DC current; a control module, which acquires electrical energy from the power supply current, determines that operation is in the charging mode or energy release mode, and acquires a first detection value provided by the current sensor module; and a self-calibration module, which generates a predetermined current flowing through the current sensor module in a self-calibration process; wherein the control module calibrates the first detection value on the basis of a second detection value of the predetermined current. The embodiments of the present invention ensure measurement precision after long-term use in harsh conditions.