Primary-Side Converter Transformer for High-Current DC Loads

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Solution Overview

Problem

Existing devices for supplying power to DC loads, such as PEM electrolyzers, face challenges in providing high supply currents due to low voltage, resulting in high losses and limited control dynamics in semiconductors on the secondary side of the transformer.

Innovation Solution

The transformer arrangement is connected on the grid side to a polyphase supply grid via the converter, and on the load side to the DC load, with the converter configured to produce a load-side DC current. This configuration places the converter on the primary side (grid side) of the transformer, allowing it to handle grid-side currents rather than high output currents, thereby reducing losses and improving control dynamics.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Loss of energy

If the converter is installed on the secondary side of the transformer, then the DC load can be supplied with power, but the high currents result in very high losses in the semiconductors

Engineering Contradiction:

Improvesemiconductor lossesVSAvoidconverter positioning

Core Design Contradiction:

Loss of energyVSDevice complexity

Solution Approach 1:

The patent inverts the conventional arrangement by placing the converter on the primary side (grid side) of the transformer instead of the secondary side (load side). This inversion allows the converter to handle grid-side currents which are lower than the high output currents required by the DC load, thereby significantly reducing semiconductor losses while maintaining the ability to supply power to the DC load

Inventive Principle:

Principle #13The other way round (Inversion)

2Ease of operation

If the converter is installed on the secondary side of the transformer, then the DC load can be supplied with power, but the control dynamics of the converter are limited

Engineering Contradiction:

Improvecontrol dynamicsVSAvoidsemiconductor losses

Core Design Contradiction:

Ease of operationVSLoss of energy

Solution Approach 1:

The patent resolves this contradiction by inverting the converter's position to the primary side, where it operates with better control dynamics due to the transformer's isolation and the ability to control the primary current independently. This positioning improves control responsiveness without the semiconductor loss penalties of the secondary-side arrangement

Inventive Principle:

Principle #13The other way round (Inversion)

3Power

If high supply currents are provided to the DC load, then the power conversion capacity increases, but the semiconductor losses increase significantly

Engineering Contradiction:

Improvepower conversion capacityVSAvoidsemiconductor losses

Core Design Contradiction:

PowerVSLoss of energy

Solution Approach 1:

The patent inverts the current flow arrangement so that the converter handles the lower grid-side currents on the primary side while the transformer handles the high current transmission to the DC load on the secondary side. This allows high power conversion capacity to be achieved while the converter's semiconductor losses remain low because it operates at lower currents

Inventive Principle:

Principle #13The other way round (Inversion)

Solution Approach 2:

The transformer acts as an intermediary device that decouples the converter from the high-current DC load. The converter only needs to handle grid-side currents, and the transformer handles the current transformation and high-current transmission to the load, thereby protecting the converter's semiconductors from high current stress and associated losses

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

This configuration reduces semiconductor losses and improves control dynamics, enabling high-accuracy automatic control of secondary currents with minimal residual ripple, and allows for scalable and flexible integration into DC grids, such as in solar farms.

Implementation Method 1

The invention relates to a device for supplying power to a DC load using a transformer arrangement and a converter

Methodology Applied

Scientific EffectElectromagnetic induction: Electromagnetic Induction

Implementation Method 2

The latter is needed in order to rectify the grid current and to ensure that the power to be converted is automatically controllable

Methodology Applied

Scientific EffectRectification: Diode

Data Source

PatentUS20250158540A1Device and method for supplying power to a DC load

Publication Date: 2025.05.15 SIEMENS ENERGY GLOBAL GMBH & CO KG

AI summary

The invention relates to a device for supplying a DC load with a transformer arrangement and a converter. The invention is characterized in that the transformer arrangement is connected on the mains side by the converter to a supply network and on the load side to the DC load to be supplied. A direct current is generated on the load side by regulation of the converter. The invention further relates to a method for supplying a DC load by the device according to the invention.