Isolation Amplifier Layout for EMI-Resistant Impedance Measurement
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Solution Overview
Problem
High-precision impedance measurement in large-capacity, high-voltage electrochemical energy devices is hindered by electromagnetic interference and requires high-cost components, posing safety risks and challenges in miniaturization due to the need for extensive shielding and high-voltage capacitors.
Innovation Solution
A high-precision impedance measurement device with a preamplifier disposed close to the electrochemical energy device terminal to amplify only signals, using an isolation amplifier to achieve high common-mode rejection ratios and operate at low voltages, thereby reducing electromagnetic interference and eliminating the need for high-voltage capacitors.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If wirings are shortened and electromagnetic interference shielding is applied, then electromagnetic interference is reduced, but the minimum separation distance for safe operation makes complete shielding difficult
Solution Approach 1:
An isolation amplifier is introduced as an intermediary component between the high-voltage electrochemical energy device and the measurement device. This isolation amplifier provides galvanic isolation, effectively blocking electromagnetic interference and high-voltage noise from coupling into the measurement circuitry, thereby achieving EMI reduction without requiring extensive physical shielding or separation distance
Solution Approach 2:
The patent replaces the mechanical/physical approach of electromagnetic shielding (using metal enclosures, grounding, and physical separation) with an electrical/electronic approach using an isolation amplifier. This substitution eliminates the need for complex physical shielding structures while achieving the same EMI rejection goal
2Measurement precision
If high-cost components are used to obtain a high common-mode rejection ratio, then measurement precision is improved, but cost increases
Solution Approach 1:
The isolation amplifier serves as a mediator that provides high common-mode rejection ratio (CMRR) without requiring expensive high-precision components in the subsequent measurement circuitry. By performing the rejection function at the isolation stage, the patent achieves high measurement precision while using cost-effective components throughout the system
3Ease of operation
If measurement wirings are exposed to high-voltage for operation, then measurement function is maintained, but safety problems occur
Solution Approach 1:
The isolation amplifier acts as a safety intermediary that galvanically isolates the high-voltage measurement wirings from the low-voltage measurement device. This allows the measurement function to operate at high voltage while protecting the measurement device and operators from high-voltage hazards, effectively resolving the safety concern without compromising operational capability
Solution Approach 2:
The patent segments the measurement system into two isolated domains: a high-voltage domain for measurement wiring connection to the electrochemical energy device, and a low-voltage domain for the measurement device. The isolation amplifier creates an electrical boundary between these segments, allowing each to operate at its appropriate voltage level safely
4Reliability
If high-voltage capacitors are used for insulation, then insulation is achieved, but device size increases and cost increases
Solution Approach 1:
The patent replaces the physical/electrical insulation approach using high-voltage capacitors with a magnetic/optical isolation approach using an isolation amplifier. This substitution eliminates the need for large, expensive high-voltage capacitors while achieving the same insulation performance, thereby reducing device volume and cost
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 provides high resistance against electromagnetic interference, improves safety, enables miniaturization, and reduces costs by using an isolation amplifier for insulation instead of high-voltage capacitors, allowing for precise impedance measurement.
Implementation Method 1
remove a DC signal from a signal input through a wiring, allow an AC signal of the signal to pass therethrough
Implementation Method 2
amplifier connected to each connection terminal of the electrochemical energy device and configured to remove a DC signal of a signal introduced through a wiring, allow an AC signal of the signal to pass therethrough, and amplify and provide the AC signal
Implementation Method 3
amplify and provide the AC signal
Implementation Method 4
disposes a preamplifier close to a terminal of an electrochemical energy device to amplify only signals, without amplifying a noise introduced into a wiring, thereby having high resistance against electromagnetic interference
Data Source
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.