AC/DC Closed-Loop Current Sensor with TMR Chip and Segmented Feedback
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Solution Overview
Problem
Existing closed-loop current sensors with complex feedback circuits struggle to accurately measure current components due to chaotic signals, failing to effectively detect specific current signals.
Innovation Solution
An AC/DC closed-loop current sensor is designed with a magnetism gathering iron core, a TMR chip, and signal processing circuits that include bandpass filtering, DC filtering, and dual-phase lock-in amplification, allowing for selective amplification and feedback of current signal components to achieve precise measurements.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If complex feedback circuits are used in closed-loop current sensors, then measurement capability is enhanced, but signal accuracy deteriorates due to chaotic signals
Solution Approach 1:
The feedback circuit is segmented into multiple parallel paths: a first feedback circuit for AC current components and a second feedback circuit for DC current components. This segmentation allows each circuit to process specific signal types independently, preventing signal chaos and improving measurement accuracy while maintaining comprehensive measurement capability.
Solution Approach 2:
A signal separation mechanism acts as an intermediary between the measured current and the feedback circuits. This intermediary divides the input current into AC and DC components before they enter respective feedback circuits, enabling accurate processing of each component type without interference and resolving the contradiction between comprehensive measurement and signal accuracy.
2Measurement precision
If multiple filtering circuits are added to select current signal components, then measurement precision is improved, but device complexity increases
Solution Approach 1:
The feedback coil serves multiple functions: it provides feedback for both AC and DC current components and enables both measurement modes (AC and DC) through a single component. This multi-functionality reduces the need for separate dedicated components for each function, thereby improving measurement precision without proportionally increasing device complexity.
3Measurement precision
If dual-phase lock-in amplification circuit is used, then signal detection accuracy is improved, but power consumption increases
Solution Approach 1:
The dual-phase lock-in amplification circuit uses periodic reference signals at the operating frequency to detect AC current components. By synchronizing detection with the periodic signal, the circuit achieves high detection accuracy for periodic AC components while maintaining lower power consumption compared to continuous wide-band amplification, as it only actively amplifies when the periodic signal is present.
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 sensor accurately measures current signal components by filtering out interference and reducing power consumption, enabling efficient detection of both AC and DC signals in various measurement environments.
Implementation Method 1
The magnetism gathering iron core is configured to converge an induced magnetic field based on a measured current
Implementation Method 2
tunneling magnetoresistance (TMR) chips are widely used because of their high sensitivity and wide linear range
Implementation Method 3
The feedback coil is wound around the magnetism gathering iron core and connected to the signal generator
Data Source
AI summary
The present disclosure relates to an AC/DC closed-loop current sensor, including a magnetism gathering iron core, a TMR chip, a signal processing circuit, a signal generator, and a feedback coil. The TMR chip is arranged at an air gap of the magnetism gathering iron core and connected to the signal processing circuit. The signal processing circuit is connected to the signal generator. The feedback coil is wound around the magnetism gathering iron core and connected to the signal generator. The signal processing circuit is configured to select from the induced signal of the TMR chip and make an amplification to obtain a current signal component and send the current signal component to the signal generator. The signal generator is configured to adjust a current output to the feedback coil based on the current signal component, and output a measurement result of the selected current signal component.