Fuel Cell Boost Control for Switching Loss Reduction

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Solution Overview

Problem

Fuel cell systems face inefficiencies due to switching losses in boost devices, which can lead to unstable drive motor operation and reduced overall system efficiency, particularly when the output voltage of the fuel cell does not match the required voltage for the drive motor.

Innovation Solution

A fuel cell system that controls a boost device based on a correlation between the output voltage of the fuel cell and the motor's necessary voltage, determining whether to boost the voltage or supply it directly, thereby minimizing switching losses and ensuring stable drive motor operation.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Loss of energy

If the boost device operates intermittently to reduce switching losses, then energy efficiency improves, but the drive motor voltage stability deteriorates

Engineering Contradiction:
Improveswitching lossVSAvoidvoltage stability
Core Design Contradiction:
Loss of energyVSReliability

Solution Approach 1:

The control device predicts future motor necessary voltage based on current drive state and correlation data, allowing the boost device to be controlled in advance to maintain voltage stability without continuous operation, thereby reducing switching losses while ensuring stability when needed

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

The control device continuously monitors the correlation between fuel cell output voltage and motor necessary voltage, using this feedback to dynamically adjust boost device operation timing and duration, optimizing the balance between reducing switching losses and maintaining voltage stability

Inventive Principle:
Principle #23Feedback

2Reliability

If the boost device operates continuously to maintain voltage stability, then drive motor reliability improves, but energy efficiency deteriorates due to switching losses

Engineering Contradiction:
Improvevoltage stabilityVSAvoidswitching loss
Core Design Contradiction:
ReliabilityVSLoss of energy

Solution Approach 1:

Instead of continuous operation, the boost device operates partially based on predicted needs - the control device determines optimal operation timing and duration by analyzing drive state correlations, providing sufficient voltage stability only when and where needed rather than continuously

Inventive Principle:
Principle #16Partial or excessive action

Solution Approach 2:

The boost device operates periodically based on predicted voltage requirements rather than continuously, with the control device using correlation analysis to determine optimal periodic operation intervals that maintain stability while minimizing switching losses

Inventive Principle:
Principle #19Periodic action

3Reliability

If the fuel cell output voltage is always boosted to match motor requirements, then drive motor performance improves, but system energy efficiency deteriorates

Engineering Contradiction:
Improvedrive performanceVSAvoidsystem efficiency
Core Design Contradiction:
ReliabilityVSUse of energy by moving object

Solution Approach 1:

The control device predicts future motor voltage requirements based on current drive state and historical correlation data, allowing the system to prepare and execute boost operations only when actually needed, avoiding unnecessary energy conversion losses while ensuring drive performance is maintained

Inventive Principle:
Principle #10Preliminary action

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 the efficiency of the fuel cell system by reducing switching losses and maintaining stable drive motor performance by matching the fuel cell output voltage with the motor's requirements, improving the overall energy utilization and system stability.

Implementation Method 1

a fuel cell generating electricity with electrochemical reaction of an oxidation gas containing oxygen to a fuel gas containing hydrogen

Methodology Applied
Scientific EffectElectrochemical reaction: Fuel Cell

Data Source

PatentEP3285320B1Fuel cell system
Publication Date: 2020.02.19 TOYOTA JIDOSHA KK
  • EP3285320B1 patent drawingFigure 1
  • EP3285320B1 patent drawingFigure 2
  • EP3285320B1 patent drawingFigure 3

AI summary

In order to assure drive of a drive motor, a boost operation of a boost device is appropriately performed by judging whether a voltage supplied from a fuel cell suffices a voltage required for driving the drive motor, thereby suppressing a switching loss by the boost device. A fuel cell system is a power source for driving a load. The system includes: a drive motor driven by an electric power; a fuel cell which generates electricity by an electrochemical reaction between an oxidizing gas containing oxygen and a fuel gas containing hydrogen and supplies an electric power to the drive motor; a first boost device which can boosts the voltage outputted from the fuel cell and supplies the boosted voltage to the drive motor; and boost control means which controls voltage boost performed by the first boost device according to the relationship between the fuel cell output voltage and the voltage required by the drive motor.