Fuel Cell Startup Control via Variable Compressor Speed
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Solution Overview
Problem
Fuel cells often fail to startup due to insufficient power from the high-voltage battery, which is unable to drive the air compressor and charge the low-voltage battery simultaneously, leading to a power imbalance during startup.
Innovation Solution
A startup control method that calculates the available power of the high-voltage battery and adjusts the rotation speed of the air compressor and the opening degree of the air pressure control valve based on this power, allowing the air compressor to be driven at a variable target rotation speed and the low-voltage battery to be charged after the air compressor's driving control is completed.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If the air compressor is driven at a fixed target rotation speed during fuel cell startup, then sufficient air supply is ensured, but the high-voltage battery power is insufficient leading to startup failure
Solution Approach 1:
The patent applies dynamics by making the air compressor's target rotation speed variable rather than fixed. The control device dynamically adjusts the target rotation speed based on the available power of the high-voltage battery, allowing the system to adapt to changing power conditions during startup. This resolves the contradiction by enabling the air compressor to operate at lower speeds when power is limited while still ensuring sufficient air supply when power is available.
Solution Approach 2:
The patent changes the operational parameters of the air compressor based on the high-voltage battery's available power. Specifically, the target rotation speed parameter is adjusted according to power conditions, and the air pressure control valve opening degree is modified to compensate for reduced compressor speed. This parameter adaptation allows the system to maintain adequate air supply despite power limitations.
2Power
If the low-voltage battery is charged simultaneously with driving the air compressor, then power distribution is optimized, but the high-voltage battery power is depleted leading to charging delay
Solution Approach 1:
The patent applies preliminary action by prioritizing the air compressor driving task before low-voltage battery charging. The control device determines that when high-voltage battery power is insufficient, the air compressor should be driven first to ensure proper fuel cell startup conditions, and only after the air compressor reaches its target operation should the low-voltage battery charging begin. This sequencing prevents power depletion and charging delays.
3Quantity of substance
If the air pressure control valve opening degree is increased to compensate for reduced air compressor speed, then air supply is maintained, but system complexity increases
Solution Approach 1:
The patent employs feedback control through the air pressure control valve that adjusts its opening degree based on feedback from the air compressor's operating conditions and the fuel cell's air demand. When the compressor speed is reduced due to power limitations, the control device increases the valve opening to maintain adequate air flow to the fuel cell. This feedback mechanism automatically balances air supply requirements with available power without requiring complex manual intervention.
Data Source
AI summary
A startup control method for a fuel cell is provided. The method includes calculating available power of a high-voltage battery when a startup of the fuel cell is requested. An air compressor is then driven based on a calculated magnitude of the available power of the high-voltage battery and a low-voltage battery is charged with the power of the high-voltage battery after the driving of the air compressor is completed.