Fuel Cell Power Converter Diode Integration

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Solution Overview

Problem

The use of a dedicated protective diode in power supply systems for electric vehicles with fuel cells results in significant energy losses, inefficiency, and increased complexity due to the need for cooling mechanisms, making integration challenging.

Innovation Solution

The power supply system eliminates the need for a dedicated protective diode by using a diode associated with a power switch in the power converter, which remains open to force current through it, preventing backflow to the fuel cell, thus protecting the fuel cell without the drawbacks of a dedicated diode.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If a dedicated protective diode is added at the fuel cell output, then the fuel cell is protected from reverse current, but energy losses increase significantly and cooling means are required

Engineering Contradiction:
Improvefuel cell protectionVSAvoidenergy losses
Core Design Contradiction:
ReliabilityVSLoss of energy

Solution Approach 1:

The patent merges the protective diode function with an existing diode in the power conversion device by keeping the associated power switch open. This eliminates the need for a dedicated protective diode, reducing energy losses while maintaining fuel cell protection from reverse current.

Inventive Principle:
Principle #5Merging (Combining)

Solution Approach 2:

The existing diode in the power conversion device is made to serve dual purposes: its normal rectification function and the additional function of protecting the fuel cell from reverse current. This is achieved by controlling the power switch to remain open, forcing current to pass through the diode in the correct direction only.

Inventive Principle:
Principle #6Universality (Multi-functionality)

2Reliability

If a dedicated protective diode is added at the fuel cell output, then the fuel cell is protected from reverse current, but the system mass increases and space requirements increase

Engineering Contradiction:
Improvefuel cell protectionVSAvoidsystem mass
Core Design Contradiction:
ReliabilityVSWeight of moving object

Solution Approach 1:

The protective function is merged into the existing power conversion device structure. By utilizing the diode already present in the converter and controlling its associated power switch, the system achieves fuel cell protection without adding separate protective components, thereby avoiding increased mass and space requirements.

Inventive Principle:
Principle #5Merging (Combining)

Solution Approach 2:

The dedicated protective diode is extracted from the system design entirely. Instead of adding a separate component, the invention removes the need for it by repurposing the existing diode in the power conversion device through appropriate switch control.

Inventive Principle:
Principle #2Taking out (Extraction)

3Reliability

If a dedicated protective diode is added at the fuel cell output, then the fuel cell is protected from reverse current, but the device complexity increases due to additional cooling means

Engineering Contradiction:
Improvefuel cell protectionVSAvoidcooling means
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The protective function is integrated into the existing power conversion device without requiring separate cooling subsystems. By using the diode already present in the converter and controlling its power switch, the system achieves protection without the thermal management complexity that would accompany a dedicated protective diode.

Inventive Principle:
Principle #5Merging (Combining)

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 configuration enhances the reliability, efficiency, and integration ease of the power supply system by eliminating energy losses and the need for cooling, while maintaining fuel cell protection.

Implementation Method 1

the power converter includes at least a first diode, and the power supply system is configured to force a current supplied by the fuel cell to pass through said first diode

Methodology Applied
Scientific EffectDiode effect: Diode

Data Source

PatentEP3869663A1Power supply systems and associated electric vehicle
Publication Date: 2021.08.25 ALSTOM HOLDINGS SA
  • EP3869663A1 patent drawingFigure 1
  • EP3869663A1 patent drawingFigure 2
  • EP3869663A1 patent drawingFigure 3

AI summary

An electrical power supply system (4), particularly for an electric vehicle (2), comprises a first electrical power supply device (20), a fuel cell (24), and a power conversion device (14) capable of electrically supplying an electrical load (6). The conversion device includes a power bus (52) and a power converter (34), in which: - the first power supply device is connected to the power bus, - the fuel cell is connected to the power bus via the power converter, - the power converter includes at least one first diode (D1), and - the power supply system, and in particular the power conversion device, is configured to force a current supplied by the fuel cell, when used as an energy source to power the power conversion device, to pass through said first diode.