Fuel Cell OCV Removal via Initial Charge Circuit
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Solution Overview
Problem
Existing fuel cell systems face challenges in controlling open circuit voltage (OCV) during power generation, leading to reduced performance and life, especially due to the use of passive resistors which cause heating and voltage quality issues, and require separate batteries for voltage management.
Innovation Solution
An apparatus comprising a power converter and a controller that links current to the system or load to reduce OCV by monitoring and adjusting voltage, using switching elements and initial charge circuits to minimize inrush currents and noise, without the need for a separate battery.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a resistor is used to buck voltage and remove OCV, then the OCV can be removed, but heating occurs and performance of the stack is reduced
Solution Approach 1:
The patent introduces an initial charge circuit as an intermediary component between the fuel cell stack and the power converter. This circuit includes a switching element and capacitor that temporarily store and dissipate the OCV energy without converting it directly to heat through a resistor, thereby removing OCV while minimizing energy loss as heat.
Solution Approach 2:
The patent changes the operational parameters by controlling the switching element to operate at specific timing and duration, transforming the OCV removal process from a continuous resistive dissipation to a controlled, intermittent charging process that reduces overall energy loss and heating.
2Reliability
If voltage is adjusted through switching using a resistor, then OCV can be controlled, but a ripple current is introduced and voltage quality is reduced
Solution Approach 1:
The initial charge circuit acts as a buffer intermediary that smooths the voltage transitions during OCV removal. The capacitor in the circuit filters out ripple currents while the switching element provides controlled voltage adjustment, maintaining voltage quality while enabling OCV control.
3Reliability
If a high voltage battery is used to remove OCV, then OCV can be removed using charging function, but a separate battery and charging/discharging device are required and control process becomes complicated
Solution Approach 1:
The patent merges the OCV removal function with the existing power converter system by integrating an initial charge circuit that uses the same switching elements and capacitors already present in the power conversion architecture. This eliminates the need for separate battery systems and charging/discharging devices, reducing overall system complexity while maintaining OCV removal capability.
4Device complexity
If a stack and load are connected one to one in fuel cell for power generation, then the system is simple, but it is impossible to control OCV
Solution Approach 1:
The patent segments the connection between the fuel cell stack and the load by introducing an initial charge circuit with switching elements. This segmentation allows independent control of the OCV removal path from the main power generation path, enabling OCV control while maintaining overall system simplicity through modular 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
Effectively controls OCV, reduces heating, and maintains fuel cell performance and life by integrating power conversion and voltage management within the system, eliminating the need for separate batteries and improving voltage quality.
Implementation Method 1
A fuel cell system generates power using hydrogen or the like
Implementation Method 2
a power converter that converts and supplies power generated by the fuel cell to a system or load
Implementation Method 3
links current to the system or load to reduce an open circuit voltage (OCV) of the fuel cell
Data Source
AI summary
An apparatus for converting power of a fuel cell for power generation to remove an open voltage of the fuel cell and a method thereof are provided. A controller links current to a system or load to reduce an open circuit voltage (OCV) of the fuel cell before power generation of the fuel cell is started, after the fuel cell is started. A power converter converts and supplies power generated by the fuel cell to the system or load. The apparatus removes an OCV of a fuel cell stack to prevent performance and life of the fuel cell from being reduced.