Fuel Cell Startup Charging Control for Supercapacitor Voltage Matching

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Solution Overview

Problem

In fuel cell vehicles, the voltage difference between the supercapacitor and the cell stack can cause overcurrent, damaging the boost converter during startup, and the time required to charge the supercapacitor to match the stack voltage increases startup time.

Innovation Solution

A fuel cell vehicle system with a boost converter and an initial charging converter, controlled by a controller, connects the output of the boost converter to the supercapacitor when the capacitor voltage exceeds the stack voltage, ensuring efficient charging and reducing startup time.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If the supercapacitor is charged using the boost converter during startup, then the voltage matching between supercapacitor and cell stack is improved, but the startup time is prolonged due to the slow charging process

Engineering Contradiction:

Improvevoltage matchingVSAvoidstartup time

Core Design Contradiction:

ReliabilityVSLoss of time

Solution Approach 1:

The patent applies preliminary action by pre-charging the supercapacitor using the initial charging converter before the boost converter takes over. This preliminary charging action raises the supercapacitor voltage to a level closer to the cell stack voltage, reducing the voltage differential that would otherwise cause prolonged charging time through the boost converter. The initial charging converter performs the time-consuming voltage matching task in advance, allowing the system to transition more quickly to normal operation.

Inventive Principle:

Principle #10Preliminary action

2Adaptability or versatility

If the supercapacitor voltage is lower than the cell stack voltage during startup, then the system can operate with standard voltage levels, but overcurrent occurs that may damage the boost converter

Engineering Contradiction:

Improvevoltage level compatibilityVSAvoidovercurrent damage

Core Design Contradiction:

Adaptability or versatilityVSObject-affected harmful factors

Solution Approach 1:

Inventive Principle:

Principle #10Preliminary action

Solution Approach 2:

The patent introduces an initial charging converter as an intermediary device between the cell stack and the supercapacitor. This intermediary converter performs the initial voltage matching and charging function, protecting the main boost converter from exposure to harmful overcurrent conditions. The intermediary handles the problematic voltage differential scenario, allowing the main boost converter to operate only under safe voltage matching conditions.

Inventive Principle:

Principle #24Intermediary (Mediator)

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

The system allows for rapid completion of startup by managing voltage levels, preventing boost converter damage and reducing the overall startup time to approximately 4 seconds, compared to 20 seconds in traditional methods.

Implementation Method 1

a boost converter configured to receive and boost a first target voltage from the cell stack and to output a boosted first target voltage

Methodology Applied

Scientific EffectElectromagnetic induction: Electromagnetic Induction

Implementation Method 2

an initial charging converter configured to receive and boost a second target voltage from the cell stack and to output a boosted second target voltage

Methodology Applied

Scientific EffectElectromagnetic induction: Electromagnetic Induction

Implementation Method 3

a supercapacitor

Methodology Applied

Scientific EffectCapacitance: Capacitance

Data Source

PatentUS12597618B2Fuel cell vehicle, method of controlling startup thereof, and recording medium storing program to execute the method

Publication Date: 2026.04.07 HYUNDAI MOTOR CO LTD

AI summary

A fuel cell vehicle of the disclosure includes a cell stack, a boost converter receiving a first target voltage from the cell stack, a supercapacitor, an initial charging converter receiving a second target voltage from the cell stack, a first switching unit configured to be switched in response to a first control signal to connect an output side of the boost converter to the supercapacitor, a second switching unit configured to be switched in response to a second control signal to connect an output side of the cell stack to the initial charging converter, and a controller configured to generate the first and second control signals in order to connect the output side of the boost converter to the supercapacitor while the output from the initial charging converter is charged in the supercapacitor so that the supercapacitor is charged until startup is completed by receiving the first target voltage.