Fuel Cell Air Compressor Control Using Valve Resistance Estimation
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Solution Overview
Problem
Turbo-type air compressors in fuel cell systems face challenges in accurately controlling gas flow rate and pressure ratio due to high pressure ratio dependence on gas flow rate, leading to deteriorated controllability and reduced durability.
Innovation Solution
A fuel cell system with an air compressor, sensors, and a calculator that estimates flow resistance, total pressure, partial pressure, and energy using specific calculation formulas, allowing for precise control of gas flow rate and pressure ratio by measuring flow rate, atmospheric pressure, rotational frequency, and valve openings.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Stress or pressure
If a turbo-type air compressor is used to supply oxidant gas to the fuel cell, then the pressure ratio can be increased, but the controllability of gas flow rate deteriorates due to high pressure ratio dependence on gas flow rate
Solution Approach 1:
The system segments the control of gas flow rate and pressure ratio into independent control loops. The gas flow rate is controlled by adjusting the compressor rotational speed, while the pressure ratio is controlled by adjusting the discharge valve opening degree. This segmentation allows independent control of each parameter, resolving the coupling issue inherent in turbo-type compressors.
Solution Approach 2:
The system dynamically adjusts both the compressor rotational speed and discharge valve opening degree in real-time based on feedback from flow rate sensors and pressure sensors. This dynamic control enables the system to maintain desired gas flow rate and pressure ratio independently, even under varying operating conditions.
2Reliability
If accurate control of gas flow rate and pressure ratio is implemented, then controllability and durability are improved, but the calculation load and complexity increase
Solution Approach 1:
The system implements feedback control using sensors to measure actual gas flow rate, pressure, and valve opening degree. The controller continuously compares measured values with target values and adjusts compressor speed and valve opening accordingly. This feedback mechanism ensures accurate control while using straightforward control logic that minimizes computational complexity.
Solution Approach 2:
The system uses readily available sensor data (flow rate, pressure, temperature, valve position) to automatically calculate and adjust operating parameters without requiring complex external calculations or interventions. The controller self-regulates the system based on real-time measurements, simplifying the overall control architecture.
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
Accurate control of gas flow rate and pressure ratio improves controllability and durability, minimizing calculation errors and reducing the calculation load on the system.
Implementation Method 1
a flow rate sensor configured to measure a flow rate of the oxidant gas supplied from the outside to an inlet of the air compressor
Implementation Method 2
an atmospheric pressure sensor configured to measure atmospheric pressure
Implementation Method 3
an outside temperature sensor configured to measure outside temperature
Implementation Method 4
a rotational frequency sensor configured to measure a rotational frequency of the air compressor
Implementation Method 5
an angle sensor configured to measure an opening degree of each of the valves that are the oxidant gas outlet valve and the bypass valve
Implementation Method 6
a calculator configured to estimate a flow resistance Zd, total pressure, partial pressure and energy of each of members that are the air compressor, the oxidant gas outlet valve and the bypass valve
Implementation Method 7
an air compressor configured to supply oxidant gas to the fuel cell
Implementation Method 8
an oxidant gas outlet valve disposed in the oxidant gas discharge flow path to control pressure of the oxidant gas
Implementation Method 9
a bypass valve disposed in the bypass flow path to control an opening state of the bypass flow path
Implementation Method 10
A fuel cell (FC) is a power generation device that generates electrical energy by electrochemical reaction between hydrogen (H2), which serves as fuel gas, and oxygen (O2), which serves as oxidant gas
Implementation Method 11
the hydrogen supplied from the gas flow path and the gas diffusion layer is protonated by the catalytic activity of the catalyst layer
Implementation Method 12
a membrane electrode assembly (MEA) and, as needed, two separators sandwiching the membrane electrode assembly. The membrane electrode assembly has such a structure, that a catalyst layer and a gas diffusion layer are formed in this order on both surfaces of a solid polymer electrolyte membrane having proton (H+) conductivity
Data Source
AI summary
Provided is a fuel cell system configured to accurately control the gas flow rate and pressure ratio of a turbo-type air compressor. The fuel cell system is a fuel cell system comprising: a fuel cell, an air compressor, an oxidant gas supply flow path, an oxidant gas discharge flow path, an oxidant gas outlet valve, a bypass flow path, a bypass valve, an atmospheric pressure sensor, an outside temperature sensor, a flow rate sensor, a rotational frequency sensor, an angle sensor, a controller, and a calculator configured to estimate the flow resistance Zd, total pressure, partial pressure and energy of each of members that are the air compressor, the oxidant gas outlet valve and the bypass valve.