Synchronous Motor-Generator Conversion for Grid-Stable Hydrogen Electrolysis

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Solution Overview

Problem

Existing hydrogen production methods, particularly water electrolysis, lack flexibility and energy efficiency, especially when integrating renewable energy sources, leading to inefficiencies and increased costs due to harmonic oscillations and reactive power demands.

Innovation Solution

Employing synchronous electric machines in the form of synchronous motor-generator sets (SMGS) for current conversion, which operate as both motors and generators, allowing for flexible operation and reduced harmonic oscillations, thereby stabilizing the mains and reducing the need for additional filters and reactive power compensation.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Loss of energy

If conventional current conversion arrangements are used for water electrolysis, then hydrogen production can be achieved, but harmonic oscillations and reactive power demands increase, reducing energy efficiency and grid stability

Engineering Contradiction:

Improveenergy efficiencyVSAvoidharmonic oscillations

Core Design Contradiction:

Loss of energyVSObject-generated harmful factors

Solution Approach 1:

The patent replaces conventional electronic current conversion arrangements with a mechanical synchronous motor-generator set. The synchronous motor converts grid AC power to mechanical rotation, which drives a synchronous generator that produces clean AC power for rectification. This mechanical substitution eliminates the harmonic oscillations and reactive power issues inherent in electronic converters, achieving near 100% energy efficiency while generating grid-stabilizing effects through the system's rotational inertia.

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

2Reliability

If synchronous motor-generator sets are used for current conversion, then energy efficiency and grid stability improve, but device complexity increases

Engineering Contradiction:

Improvegrid stabilityVSAvoiddevice complexity

Core Design Contradiction:

ReliabilityVSDevice complexity

Solution Approach 1:

The synchronous motor-generator set performs multiple functions simultaneously: it converts electrical energy to mechanical energy and back to electrical energy with minimal losses, provides rotational inertia for grid stabilization, and generates clean sinusoidal AC power that eliminates harmonics. This multi-functionality justifies the increased device complexity by delivering superior reliability, energy efficiency, and grid support capabilities that conventional single-function converters cannot achieve.

Inventive Principle:

Principle #6Universality (Multi-functionality)

3Productivity

If large-scale hydrogen production is implemented, then hydrogen supply increases, but negative feedback on the electrical grid increases due to harmonic oscillations

Engineering Contradiction:

Improvehydrogen production scaleVSAvoidnegative feedback on grid

Core Design Contradiction:

ProductivityVSObject-generated harmful factors

Solution Approach 1:

The patent replaces electronic current converters with synchronous motor-generator sets to enable large-scale hydrogen production without grid degradation. The mechanical conversion system produces clean sinusoidal AC power that eliminates harmonic oscillations, allowing electrolyzers to operate at full capacity without generating negative feedback on the electrical grid.

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

Solution Approach 2:

The synchronous motor-generator set provides positive feedback to the grid through its rotational inertia, which stabilizes frequency and voltage fluctuations. The system's mechanical energy storage in rotating masses acts as a buffer that absorbs and releases energy to maintain grid stability, enabling scalable hydrogen production without compromising electrical infrastructure.

Inventive Principle:

Principle #23Feedback

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

Enhances flexibility and energy efficiency by stabilizing the mains, reducing investment costs, and minimizing harmonic oscillations, enabling large-scale hydrogen production without negative feedback on the electrical grid.

Implementation Method 1

one or more first synchronous electric machines which are operable as motors and one or more second synchronous electric machines which are operable as generators

Methodology Applied

Scientific EffectElectromagnetic induction: Electromagnetic Induction

Implementation Method 2

method for producing hydrogen by means of water electrolysis

Methodology Applied

Scientific EffectElectrolysis: Electrolysis

Data Source

PatentUS20260022470A1Method and plant for producing hydrogen

Publication Date: 2026.01.22 LINDE AG

AI summary

A method for producing hydrogen by means of water electrolysis, in which a direct electrolysis current is fed to one or more electrolysis units at least in a first operating mode, wherein the direct electrolysis current is supplied from a mains current using a current conversion arrangement, wherein the mains current is an alternating current, wherein the current conversion arrangement, comprises one or more first synchronous electric machines which are operable as motors and one or more second synchronous electric machines which are operable as generators, wherein the one or more first synchronous electric machines is/are operated using the mains current, wherein the one or more second synchronous electric machines is/are driven using the one or more first synchronous electric machines, and wherein the direct electrolysis current is supplied using the one or more second synchronous electric machines. The present invention also relates to a corresponding plant.