Fuel Cell AC Impedance Measurement Stabilization
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Solution Overview
Problem
Conventional techniques for measuring AC impedance in fuel cells suffer from reduced precision due to variations in output current caused by auxiliary equipment, leading to inaccurate impedance readings, especially when low frequency sine wave signals are applied.
Innovation Solution
A fuel cell system with power generation stabilizing means and impedance measuring means that stabilize power generation before measuring AC impedance, using a storage device to manage power surpluses and deficiencies, and stopping measurements when power limits are reached to ensure accurate readings.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Difficulty of detecting and measuring
If low frequency sine wave signal is applied to measure AC impedance, then moisture condition detection capability is improved, but measurement precision deteriorates due to current variation from auxiliary equipment
Solution Approach 1:
The patent applies preliminary action by stabilizing the power generation output of the fuel cell before performing AC impedance measurement. The control device adjusts the output current to a predetermined value and maintains it stable during the measurement process, thereby eliminating current variations caused by auxiliary equipment operations and enabling precise low-frequency impedance measurement for accurate moisture condition detection
2Measurement precision
If power generation is stabilized by controlling output current, then measurement precision is improved, but device complexity increases due to additional control mechanisms
Solution Approach 1:
The patent applies universality by making the control device perform multiple functions: it not only controls the power output stabilization during impedance measurement but also manages the overall power distribution to auxiliary equipment and handles the AC signal application for measurement. This multi-functionality reduces the need for separate dedicated control systems, thereby limiting the increase in device complexity while maintaining high measurement precision
Data Source
AI summary
A fuel cell system capable of measuring AC impedance comprises: power generation stabilizing means for stabilizing power generation in a fuel cell, and impedance measuring means for measuring the AC impedance after power generation in the fuel cell has been stabilized. Since the AC impedance in a low frequency range is measured after power generation in the fuel cell is stabilized, no external disturbance occurs during measurement, and the AC impedance can be measured with a high degree of precision. Thus, a fuel cell system and a measuring method with which AC impedance can be measured with a high degree of precision can be provided.