Modular H-Bridge DC-DC Converter Control for Electrolysis Power
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Solution Overview
Problem
Existing DC-DC converters for electrolysis devices require a connection to a medium-voltage AC grid and lack an efficient means to directly utilize low-voltage DC grid systems, such as those from solar cells or wind energy, leading to inefficiencies in energy conversion.
Innovation Solution
A self-commutating multilevel DC-DC converter with an H-bridge arrangement and interphase transformers, utilizing bipolar transistors, allows for direct conversion of DC input voltage to output voltage without inversion, enabling a modular design adaptable to load requirements and reducing transformation losses by adjusting the actuation signal sequence based on the number of DC voltage converter units.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of energy
If a connection to a medium-voltage AC grid system is used to supply DC current to electrolysis devices, then reliable power supply is achieved, but transformation losses increase and direct utilization of low-voltage DC grid systems (solar cells, wind energy) is not possible
Solution Approach 1:
Instead of converting AC to DC through rectification (the conventional approach), the patent inverts the approach by directly converting DC to DC using a DC-DC converter with H-bridge arrangement. This eliminates the AC intermediate step and associated transformation losses, while enabling direct connection to low-voltage DC grid systems from solar cells or wind energy.
Solution Approach 2:
The patent introduces a DC-DC converter with H-bridge arrangement and interphase transformers as an intermediary device between the low-voltage DC grid system and the electrolysis device. This intermediary enables direct DC-to-DC conversion without requiring AC grid connection, reducing transformation losses while maintaining adaptability to different DC sources.
2Power
If the number of DC voltage converter units is increased to meet higher load demands, then power capacity increases, but switching losses increase due to greater number of switching elements
Solution Approach 1:
The patent employs periodic actuation of semiconductor switching elements with optimized pulse sequences. By carefully timing the switching actions and using interphase transformers, the system achieves high power capacity while minimizing switching losses through reduced switching frequency and optimized switching patterns across multiple parallel converter units.
Solution Approach 2:
The patent divides the DC-DC converter into multiple parallel DC voltage converter units, each handling a portion of the total power. This segmentation allows the system to scale power capacity by adding units while maintaining efficient switching operation in each unit, preventing excessive switching losses that would occur in a single large converter.
3Adaptability or versatility
If conventional rectifiers (thyristors) are used for AC to DC conversion, then connection to AC grid is achieved, but direct connection to low-voltage DC grid systems is not possible and transformation losses occur
Solution Approach 1:
The patent replaces the conventional AC-to-DC rectification mechanism (using thyristors and AC grid connection) with a direct DC-to-DC conversion mechanism using H-bridge arranged semiconductor switching elements. This substitution eliminates the need for AC grid connection and intermediate transformation steps, enabling direct connection to low-voltage DC grid systems while minimizing transformation losses.
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 solution enables efficient energy conversion with reduced switching and transformation losses, maintaining or improving energy efficiency by directly connecting a low-voltage DC grid to an electrolysis device, and can be configured to meet varying load demands.
Implementation Method 1
for the direct conversion of a DC electric input voltage into a DC electric output voltage
Implementation Method 2
H-bridge arrangement with interphase transformers connected down-circuit
Implementation Method 3
The actuatable semiconductor switching elements can be bipolar transistors which are configured e.g. in the form of IGBTs
Data Source
AI summary
The invention relates to a method for operating a DC-DC converter for supplying an electrolysis device with electrical operating power, in which in a step at least four controllable semiconductor switching elements in an H-bridge arrangement with interphase transformers connected downstream are controlled by a predetermined control signal sequence for direct conversion of an electrical input DC voltage into an electrical output DC voltage. At least two DC voltage converter units are used, each having four controllable semiconductor switching elements in an H-bridge arrangement with interphase transformers connected downstream, the following steps being carried out: detecting a number of the DC voltage converter units, and adapting the control signal sequence to the detected number of DC voltage converter units.