Fuel Cell Startup Bypass Circuit for DC/DC Converter Losses
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Solution Overview
Problem
Existing fuel cell systems face energy losses and reliability issues during startup due to the need for energy transmission through a DC/DC converter, which can fail and requires a large energy storage system to power the air pump.
Innovation Solution
A method that bypasses the DC/DC converter by directly connecting the energy storage to the power feeding circuit, allowing electrical energy to be supplied directly to the air pump, thereby avoiding switching losses and ensuring reliable startup even if the DC/DC converter fails.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of energy
If the DC/DC converter is used to supply energy from the accumulator to the air pump during startup, then the energy transmission is achieved, but energy losses occur in the DC/DC converter
Solution Approach 1:
The power supply system is segmented into two independent paths: a normal path through the DC/DC converter for regular operation, and a bypass path directly connecting the accumulator to the air pump for startup operations. This segmentation allows each path to be optimized for its specific function, eliminating energy losses in the bypass path while maintaining the DC/DC converter for normal regulated operation.
Solution Approach 2:
A bypass circuit is introduced as an intermediary path that mediates between the accumulator and air pump during startup. This bypass circuit includes a bypass switch that can be activated to create a direct connection, avoiding the DC/DC converter and its associated energy losses during the critical startup phase.
2Quantity of substance
If the accumulator is sized to supply sufficient energy to the air pump through the DC/DC converter, then the startup energy requirement is met, but the accumulator size becomes relatively large
Solution Approach 1:
The power supply system is segmented into two independent paths: a normal path through the DC/DC converter for regular operation, and a bypass path directly connecting the accumulator to the air pump for startup operations. This segmentation allows each path to be optimized for its specific function, eliminating energy losses in the bypass path while maintaining the DC/DC converter for normal regulated operation.
Solution Approach 2:
The system changes the electrical connection parameters during startup by closing the bypass switch to create a direct low-resistance path from the accumulator to the air pump. This parameter change (switching from series connection through DC/DC converter to parallel direct connection) reduces the total resistance and energy losses, allowing for a smaller accumulator size.
3Reliability
If the DC/DC converter is used for energy transmission, then the fuel cell system can operate, but the system cannot start if the DC/DC converter fails
Solution Approach 1:
The bypass circuit is pre-configured and ready before startup, providing a backup path that cushions against potential DC/DC converter failures. By having this alternative path prepared in advance, the system ensures that startup can proceed even if the DC/DC converter is faulty or fails during the startup process.
Solution Approach 2:
The system changes the electrical connection parameters during startup by closing the bypass switch to create a direct low-resistance path from the accumulator to the air pump. This parameter change (switching from series connection through DC/DC converter to parallel direct connection) reduces the total resistance and energy losses, allowing for a smaller accumulator size.
4Productivity
If the DC/DC converter is used during startup, then the power feeding circuit is maintained, but switching losses occur reducing efficiency
Solution Approach 1:
The DC/DC converter is extracted from the startup path and placed only in the normal operation path. During startup, the bypass circuit provides a direct connection that completely removes the DC/DC converter from the energy transmission path, eliminating all switching losses and improving startup efficiency.
Solution Approach 2:
The bypass circuit allows the energy to skip through the DC/DC converter during startup, rushing directly from the accumulator to the air pump. This skipping of the intermediate conversion stage eliminates the time and energy losses associated with DC/DC switching operations during the critical startup phase.
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 enhances energy efficiency and reduces the size of the energy storage system while ensuring reliable fuel cell system startup, regardless of DC/DC converter functionality.
Implementation Method 1
a fuel cell for generating electricity by electrochemical reactions of a fuel gas supplied from a fuel gas supply apparatus and an oxygen-containing gas supplied from an oxygen-containing gas supply apparatus
Data Source
AI summary
A fuel cell system includes a fuel cell, a battery, and a DC/DC converter capable of connecting the fuel cell and the battery on a power feeding circuit. A method of starting operation of the fuel cell system includes the steps of connecting a bypass line connected to a battery for bypassing the DC/DC converter to the power feeding circuit, and directly supplying electrical energy from the battery to an air compressor of an oxygen-containing gas supply apparatus through the bypass line in a state where the fuel cell is disconnected from the power feeding circuit.