Fuel Cell Voltage Measurement Synchronization and Protection
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Solution Overview
Problem
Conventional fuel cell voltage measurement methods fail to accurately calculate average power due to asynchronous voltage and current measurement time points, leading to potential damage from significant voltage fluctuations and reverse voltage breakdowns.
Innovation Solution
An apparatus and method that synchronizes voltage measurement time points with current measurement time points by sequentially measuring forward and reverse voltages across a fuel cell stack, using high impedance elements to protect against reverse voltage and calculate average power by multiplying the average voltage by the measured current.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If voltage measurement is performed without protection, then measurement circuit is simple, but high reverse voltage can break down measurement elements under specific conditions
Solution Approach 1:
The patent introduces protection elements (such as diodes or transistors) as intermediaries between the voltage measurement circuit and the fuel cell unit cells. These protection elements are connected in parallel with each unit cell and remain inactive during normal operation, allowing the measurement circuit to remain relatively simple. However, when reverse voltage exceeds safe thresholds, the protection elements automatically activate to clamp or redirect the excessive voltage, preventing breakdown of measurement elements while adding minimal complexity to the overall circuit.
2Productivity
If asynchronous voltage and current measurements are used, then measurement process is faster, but significant voltage fluctuation causes inaccurate power calculation
Solution Approach 1:
The system performs preliminary voltage measurements for all unit cells sequentially before the current measurement is completed. These pre-measured voltage values are stored in temporary memory. After current measurement finishes, the system retrieves the stored voltage values and performs power calculation using both voltage and current data from the same synchronous time point. This approach maintains fast measurement speed by overlapping the voltage measurement phase with the current measurement phase, while ensuring accuracy through synchronous calculation.
Data Source
AI summary
An apparatus for measuring average power of a fuel cell may include: a voltage measurement unit configured to sequentially measure forward voltages of unit cells including a fuel cell stack from a bottom cell to a top cell, and sequentially measure reverse voltages of the unit cells from the top cell to the bottom cell; a current measurement unit configured to measure a current of an output terminal of the fuel cell stack; and a control unit configured to control the voltage measurement unit to measure the reverse voltages based on a current measurement time point, after the voltage measurement unit measures the forward voltages, and calculate average power using the forward voltages, the reverse voltages and the measured current.