Fuel Cell Vehicle Power Management Without Voltage Converter

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Solution Overview

Problem

Conventional electric motor vehicle systems require a high-expenditure electric voltage converter to manage power between fuel cell systems, accumulators, and electric motors, leading to large installation space and weight, and unnecessary stress on the accumulator.

Innovation Solution

Implementing a system where the accumulator is charged by the fuel cell system and electric motor acting as a generator without voltage conversion, using switching elements to manage power flow and an electronic control unit to optimize charging and discharging, minimizing the use of an electric voltage converter and reducing accumulator stress.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Adaptability or versatility

If an electric voltage converter is used to manage power between fuel cell system, accumulator, and electric motor, then power management capability is improved, but installation space and weight increase

Engineering Contradiction:

Improvepower management capabilityVSAvoidinstallation space and weight

Core Design Contradiction:

Adaptability or versatilityVSWeight of stationary object

Solution Approach 1:

The patent extracts and eliminates the electric voltage converter from the power management system by designing the fuel cell system and accumulator with compatible voltage levels, allowing direct power exchange without conversion equipment

Inventive Principle:

Principle #2Taking out (Extraction)

Solution Approach 2:

The fuel cell system and accumulator are designed to operate at compatible voltage levels, enabling them to directly power the electric motor and charge each other without requiring additional voltage conversion equipment

Inventive Principle:

Principle #6Universality (Multi-functionality)

2Adaptability or versatility

If an electric voltage converter is used to manage power between fuel cell system, accumulator, and electric motor, then power management capability is improved, but system cost increases

Engineering Contradiction:

Improvepower management capabilityVSAvoidsystem cost

Core Design Contradiction:

Adaptability or versatilityVSEase of manufacture

Solution Approach 1:

The patent removes the expensive electric voltage converter from the system by designing direct voltage compatibility between components, significantly reducing system cost

Inventive Principle:

Principle #2Taking out (Extraction)

3Adaptability or versatility

If the accumulator is continuously charged and discharged to meet peak power demands, then power supply flexibility is improved, but accumulator service life decreases

Engineering Contradiction:

Improvepower supply flexibilityVSAvoidaccumulator service life

Core Design Contradiction:

Adaptability or versatilityVSDuration of action of stationary object

Solution Approach 1:

The fuel cell system continuously generates electricity to meet base load demands, allowing the accumulator to operate in a more stable charging state rather than frequent deep discharge cycles, thereby extending its service life while maintaining power supply flexibility

Inventive Principle:

Principle #20Continuity of useful 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 allows for efficient operation of the fuel cell system without voltage conversion, minimizing accumulator stress and extending its service life by optimizing charging and discharging cycles, and reducing the need for an electric voltage converter.

Implementation Method 1

a fuel cell system having at least one hydrogen (air) oxygen fuel cell

Methodology Applied

Scientific EffectFuel cell electrochemical conversion: Fuel Cell

Implementation Method 2

an electric motor acting, in particular, as a vehicle driving motor

Methodology Applied

Scientific EffectElectromagnetic conversion: Electromagnetic Induction

Implementation Method 3

an accumulator and an electric motor

Methodology Applied

Scientific EffectElectrical energy storage: Battery (electricity)

Data Source

PatentUS9688160B2Operating method for an electric energy system of a motor vehicle comprising a fuel cell system, an accumulator and an electric motor

Publication Date: 2017.06.27 BAYERISCHE MOTOREN WERKE AG

AI summary

A method of operating an electric system of a motor vehicle, consisting of a fuel cell system, an accumulator and an electric driving motor is provided. Without implementing an electric voltage conversion and therefore without an electric voltage converter, as a function of the level of the electric voltage made available by the fuel cell system and by the accumulator and the electric power demanded by the electric motor, a first switching element in the connection between the fuel cell system and a node point electrically connected with the accumulator and the electric motor, as well as a second switching element in the connection between the accumulator and this node point are opened or closed as needed. This is done such that the power requirement of the electric motor is met primarily from the fuel cell system, and in an auxiliary fashion, additionally from the accumulator. If the electric power offered by the fuel cell system exceeds the electric power demanded by the electric motor, the excess power will be fed to the accumulator for as long as its permissible charging current is not exceeded and the accumulator still has a defined residual storage capacity.