Fuel Cell Power Estimation During Warm-Up via Pressure Control
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Solution Overview
Problem
Existing methods for estimating the power generation characteristic of fuel cells in low temperature regions, particularly during warm-up operations, suffer from reduced accuracy due to non-linear relationships between voltage differences and reference IV characteristics on the high load side.
Innovation Solution
A device that includes a reference characteristic setting unit, current detection unit, voltage detection unit, and characteristic estimation unit, which estimates the power generation characteristic by adjusting the gas pressure in the fuel cell to reduce the influence of log terms, allowing for accurate estimation even in low temperature regions by setting a reference power generation characteristic and calculating voltage differences using a linear function.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If a linear relationship between voltage difference and reference IV characteristic is used for estimation, then estimation simplicity is improved, but estimation accuracy deteriorates on the high load side in low temperature regions
Solution Approach 1:
The patent changes the parameter of gas pressure to a predetermined value or higher during warm-up operations. This parameter change reduces the influence of log terms in the voltage-current relationship, making the relationship more linear and improving estimation accuracy on the high load side without complicating the estimation method.
2Measurement precision
If gas pressure is increased to reduce log term influence, then estimation accuracy on high load side is improved, but energy consumption increases
Solution Approach 1:
The patent applies the pressure condition (gas pressure at predetermined value or higher) in advance during warm-up operations before normal operation begins. This preliminary action ensures accurate estimation during the critical warm-up phase without requiring continuous high pressure during normal operation, thereby limiting energy consumption increase to only the warm-up period.
3Reliability
If estimation is performed during warm-up operation, then operational reliability is improved, but estimation accuracy deteriorates due to non-linear voltage characteristics
Solution Approach 1:
The patent changes the gas pressure parameter to a predetermined value or higher during warm-up operations. This parameter change reduces the influence of log terms in the voltage-current relationship, making the relationship more linear and improving estimation accuracy on the high load side without complicating the estimation method.
Data Source
AI summary
A power generation characteristic estimation device for fuel cell includes a reference characteristic setting unit for setting a reference power generation characteristic of a fuel cell, a current detection unit for detecting an actual current of the fuel cell, a voltage detection unit for detecting an actual voltage of the fuel cell, and a characteristic estimation unit for estimating an actual power generation characteristic of the fuel cell based on a voltage difference between a voltage on the reference power generation characteristic and an actual voltage at the actual current. The characteristic estimation unit estimates the power generation characteristic during a warm-up operation of the fuel cell when a pressure of a gas supplied to the fuel cell is not lower than a predetermined value.