Fuel Cell Voltage Control for Auxiliary Stability
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Solution Overview
Problem
Fuel cells have poor starting properties and efficiency decreases with temperature drops and poisoned electrode catalysts, leading to unstable operation of auxiliary machines during catalyst recovery and warming.
Innovation Solution
A fuel cell system with a voltage conversion device, power accumulation device, and operation control means that allows the fuel cell to operate at a low-efficiency point to recover the poisoned catalyst and warm up, while maintaining stable operation of auxiliary machines by controlling voltage conversion based on the fuel cell's operation point and auxiliary machine driving voltage.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the fuel cell is operated at a low-efficiency operation point to recover the poisoned electrode catalyst and warm up, then the catalyst activity is recovered and the fuel cell temperature is raised, but the voltage of the fuel cell lowers and auxiliary machines cannot stably be operated
Solution Approach 1:
A voltage conversion device is introduced as an intermediary between the fuel cell and the auxiliary machine. This device converts the low voltage output from the fuel cell's low-efficiency operation point into the required driving voltage for the auxiliary machine, enabling the fuel cell to operate at the necessary low-efficiency point for catalyst recovery and warming while still providing adequate voltage to the auxiliary machine through voltage conversion.
2Temperature
If the fuel cell is operated at a low-efficiency operation point to recover the poisoned electrode catalyst and warm up, then the catalyst activity is recovered and the fuel cell temperature is raised, but the auxiliary machine cannot stably be operated
Solution Approach 1:
The voltage conversion device serves as a mediator that decouples the fuel cell operation from the auxiliary machine operation. It allows the fuel cell to operate independently at the low-efficiency point required for warming and catalyst recovery, while the voltage conversion device ensures the auxiliary machine receives stable driving voltage regardless of the fuel cell's operation point.
Solution Approach 2:
The system changes the operating parameters of the fuel cell to a low-efficiency operation point characterized by lower voltage and higher power loss, which generates more heat for warming and catalyst recovery. Simultaneously, the voltage conversion device adjusts the voltage parameter to maintain stable operation of the auxiliary machine, allowing the system to operate in a parameter regime that would otherwise be unsuitable for auxiliary machine operation.
3Reliability
If the voltage of the fuel cell is raised by a converter to drive the auxiliary machine, then the auxiliary machine can operate stably, but the power loss increases
Solution Approach 1:
The system intentionally operates the fuel cell at a low-efficiency operation point where the voltage is lower than optimal, accepting higher power loss as a necessary condition to generate sufficient heat for catalyst recovery and warming. The voltage conversion device then compensates for this by converting the lower voltage to the required level for the auxiliary machine, distributing the energy loss across different functions (warming, catalyst recovery, and voltage conversion).
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
Enables stable operation of auxiliary machines even during catalyst recovery and warming, ensuring continuous power supply by adjusting the fuel cell's operation point and voltage conversion to maintain necessary voltage levels.
Implementation Method 1
a fuel cell has a poor starting property as compared with another power source. A power generation efficiency of such a fuel cell decreases owing to lowering of a temperature and a poisoned electrode catalyst
Implementation Method 2
a voltage conversion device; voltage conversion control means for controlling a voltage converting operation of the voltage conversion device
Data Source
AI summary
There is disclosed a fuel cell system or the like capable of stably operating an auxiliary machine and the like, even when recovering a poisoned electrode catalyst and warming up a fuel cell. A controller derives a target operation point sufficient for recovering activity of the poisoned electrode catalyst, and realizes shift of an operation point to a target operation point in a state in which an output power is held to be constant. The operation is switched to a low-efficiency operation point, whereby an output voltage of the fuel cell lowers, but the voltage is raised to an allowable input voltage of a high-voltage auxiliary machine by a DC/DC converter.