Preamplifier Placement for Impedance Measurement EMI Resistance
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Solution Overview
Problem
Existing impedance measurement devices for large-capacity, high-voltage electrochemical energy devices face challenges in accurately measuring small AC voltage changes due to electromagnetic interference, requiring high-cost components and posing safety risks, while conventional amplifiers amplify both signals and noise, leading to low common-mode rejection ratios and increased costs.
Innovation Solution
A preamplifier is positioned close to the terminal of the electrochemical energy device to amplify only signals without amplifying noise introduced through the wiring, using an isolation amplifier for high common-mode rejection ratio and reducing costs by eliminating the need for high-voltage capacitors.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If conventional amplifiers are used to measure small AC voltage changes, then measurement sensitivity is improved, but electromagnetic interference and noise are also amplified, leading to low common-mode rejection ratio
Solution Approach 1:
The measurement system is segmented into two parts: a preamplifier placed close to the electrochemical energy device to amplify weak signals before transmission, and a main amplifier isolated from electromagnetic interference. This segmentation allows signal amplification while minimizing noise contamination.
Solution Approach 2:
A preamplifier acts as an intermediary component between the electrochemical energy device and the main measurement system. It amplifies weak AC voltage signals locally before transmission, serving as a buffer that prevents subsequent amplification of noise from long wiring.
2Reliability
If wiring length is increased to separate measurement equipment from electrochemical energy device, then safety is improved, but electromagnetic interference resistance deteriorates
Solution Approach 1:
Signal amplification is performed preliminarily at the source (near the electrochemical energy device) before the signal traverses the safety-distance wiring. By amplifying the signal to a stronger level upfront, the subsequent long-wiring transmission does not amplify noise, maintaining both safety and EMI resistance.
3Measurement precision
If high-cost components are used to achieve high common-mode rejection ratio, then measurement precision is improved, but device cost increases
Solution Approach 1:
The patent employs a cost-effective preamplifier design that achieves high common-mode rejection ratio without requiring expensive high-voltage components. The preamplifier is positioned to perform amplification locally, avoiding the need for costly shielding and isolation components that would otherwise be required.
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 configuration provides high resistance against electromagnetic interference, achieves a high common-mode rejection ratio, improves safety by operating at low voltages, and enables miniaturization and cost reduction.
Implementation Method 1
an impedance measurement device capable of achieving a high common-mode rejection ratio by using an isolation amplifier
Data Source
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AI summary
An impedance measurement device of the present disclosure includes: an electrochemical energy device; an amplifier connected to each connection terminal of the electrochemical energy device and configured to amplify a signal introduced into a wiring; and a main board configured to receive the signal from the amplifier and measure an impedance. Accordingly, the present invention has advantages in that high resistance to electromagnetic interference may be achieved by disposing a preamplifier close to a terminal of an electrochemical energy device to amplify only the signal without amplifying a noise introduced into a wiring.