Fuel Cell Air Ratio Control Eliminates DC-DC Converters
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Solution Overview
Problem
Fuel cell systems face high operating costs due to the use of expensive and lossy power converters, such as DC/DC converters, which are necessary to match and adjust the output voltage and current of fuel cell modules to the load demand.
Innovation Solution
The system employs an air supply device and a control device to adjust the air quantity supplied to the fuel cell module based on the load demand, using the stoichiometry of the oxidant as a substitute for an intermediate power converter, allowing direct connection of the load to the fuel cell module and regulating output power through air ratio control.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If a power converter (DC/DC converter) is used to match and adjust the output voltage and current of fuel cell modules to load demand, then the voltage and current matching is achieved, but the operating costs increase and energy losses occur
Solution Approach 1:
The patent extracts and removes the power converter from the fuel cell system by directly connecting the fuel cell module to the load. The air supply device then takes over the function of regulating output power through air ratio control, eliminating the need for expensive and lossy DC/DC converters while maintaining voltage and current matching capability.
Solution Approach 2:
The patent replaces the mechanical/electrical power converter system with a chemical control mechanism - specifically, controlling the air supply ratio to the fuel cell. By adjusting the air-to-fuel ratio in the electrochemical reaction, the output power is regulated without requiring intermediate power electronic conversion stages, thereby reducing energy losses.
2Adaptability or versatility
If a power converter is used to adjust output voltage and current, then the load demand is met, but the operating costs increase due to expensive components
Solution Approach 1:
The patent removes the expensive power converter component from the system architecture. Instead of using complex DC/DC conversion equipment, the system relies on the inherent electrochemical characteristics of the fuel cell combined with simple air supply control, dramatically reducing component costs while maintaining load matching capability.
Solution Approach 2:
The patent replaces expensive, complex power electronic components with simpler, more affordable air supply control mechanisms. The air ratio control system uses basic flow control devices rather than costly semiconductor switching elements, making the overall system more economically viable.
3Ease of manufacture
If the air quantity is adjusted to control output power, then the power converter is eliminated and costs are reduced, but the control precision must be maintained within safe limits
Solution Approach 1:
The patent implements a feedback control system that continuously monitors the air supply ratio and adjusts it to maintain optimal fuel cell operation. By using sensors and control algorithms, the system ensures that air ratio adjustments remain within safe operational limits while precisely controlling output power, eliminating the need for expensive power converters.
Solution Approach 2:
The patent controls the fuel cell output power by changing the air supply parameter (air ratio) rather than using power electronic conversion. By precisely controlling the amount of air supplied to the electrochemical reaction, the system achieves accurate power regulation while operating within safe limits, replacing complex power converters with simpler flow control mechanisms.
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
This approach eliminates the need for power converters, reducing operating costs and maintaining the fuel cell stack's integrity by adjusting output voltage and power within safe limits through air ratio control, thereby optimizing fuel cell system performance.
Implementation Method 1
Fuel cells generate electrical energy from hydrogen and oxygen
Implementation Method 2
an air supply device which is connected to the at least one fuel cell module for delivering air in a variable quantity of air to the fuel cell module as one of the reactants
Data Source
AI summary
A fuel cell system that includes a fuel cell module having first and second electrical supply terminals with an electrical output voltage applied thereto during operation of the fuel cell module. The electrical supply terminals are coupled to an electrical load, an air supply device that supplies air in an adjustable air quantity to the fuel cell module as one of the reactants for generating the output voltage, and a control device that controls an output power of the fuel cell module at the electrical supply terminals and adjusts the quantity of air supplied by the air supply device. The control device detects a load demand of the load and controls the output power of the fuel cell module in accordance with the detected load demand, to adjust and update the air quantity supplied by the air supply device in accordance with the detected load demand in air-ratio-controlled manner.