The main objective of the article is to provide a thorough review of currently used AC-DC converters for alkaline and proton exchange membrane (PEM) electrolyzers in power grid or wind energy conversion systems. Based on the current literature, this article aims at emphasizing the advantages and drawbacks of AC-DC converters mainly based on thyristor rectifier bridges and chopper-rectifiers. The analysis is mainly focused on the current issues for these converters in terms of specific energy consumption, current ripple, reliability, efficiency, and power quality. From this analysis, it is shown that thyristors-based rectifiers are particularly fit for high-power applications but require the use of active and passive filters to enhance the power quality. By comparison, the association combination of the chopper-rectifier can avoid the use of bulky active and passive filters since it can improve power quality. However, the use of a basic chopper (i.e., buck converter) presents several disadvantages from the reliability, energy efficiency, voltage ratio, and current ripple point of view. For this reason, new emerging DC-DC converters must be employed to meet these important issues according to the availability of new power switching devices. Finally, based on the authors’ experience in power conversion for PEM electrolyzers, a discussion is provided regarding the future challenges that must face power electronics for green hydrogen production based on renewable energy sources.

https://hal.archives-ouvertes.fr/hal-02733976/document

AC-DC Converters for Electrolyzer Applications: State of the Art and Future Challenges

Water electrolysis will be used to produce renewable hydrogen for energy storage and Power-to-X applications in the future renewable-energy-based energy systems. Therefore, the energy efficiency of hydrogen production will probably become a major issue. In this study, the effect of practical supply power converters on the specific energy consumption of megawatt (MW)-scale alkaline electrolyzers is studied and compared with an ideal dc power supply. The current quality and the stack specific energy consumption are studied in the case of traditional thyristor rectifiers and a transistor-based converter. The stack specific energy consumption is analyzed based on the simulated current waveforms and the electrical equivalent circuit of the electrolyzer stack. It is found that the transistor-based converter offers up to 14% lower electrolyzer stack specific energy consumption than the 6-pulse thyristor rectifier and up to 9.2% lower electrolyzer stack specific energy consumption than the 12-pulse thyristor rectifier as the current varies between 5000 and 1000 A. The simulated change in the stack specific energy consumption of the MW-scale alkaline water electrolyzer outweighs the losses occurring in the rectifiers. Further, selection of the ac voltage level may have a more adverse effect on the stack specific energy consumption with the thyristor rectifier topologies compared with the transistor-based topologies.

/pdf/effect-of-converter-topology-on-the-specific-energy-20zmptke8j.pdf

Effect of Converter Topology on the Specific Energy Consumption of Alkaline Water Electrolyzers

Applications such as electrolysis, electrowinning, DC arc furnaces and plasma torches require high-current (several kA) power supplies at low-voltage levels (few hundreds of volts). In this study, conventional rectifier topologies (diode- and thyristor-based multi-pulse rectifiers with on-load tap changing transformer and chopper-rectifier) used for high-current, variable-voltage applications are reviewed along with recent advancements in the field. The main applications themselves are also discussed. Issues with conventional topologies are highlighted. Power quality techniques like passive and active filters are discussed for power factor and current harmonics compensation. Advanced medium- to high-frequency transformer-based topologies (with current and voltage source rectifiers) are discussed along with simulation results.

https://ietresearch.onlinelibrary.wiley.com/doi/epdf/10.1049/iet-pel.2014.0533

High-current variable-voltage rectifiers: state of the art topologies

This paper proposes a novel and passive harmonic reduction method at dc link of multipulse rectifier (MPR). The proposed method uses a single-phase diode-bridge rectifier to generate circulating current, which can shape the input line current of MPR. The input side of the single-phase diode-bridge rectifier is connected with the secondary winding of interphase reactor (IPR), and its output side is connected with load, which can recycle the harmonic energy and feed to load. The operation mode of the single-phase diode-bridge rectifier is analyzed, and the turn ratio of the IPR is designed optimally. Under ideal condition, the proposed MPR operates as a 24-pulse rectifier, and its total harmonic distortion (THD) of input line current is about 7.6%. Most of all, the proposed method is easy to be used in different 12-pulse rectifier topologies, and its conduction losses are far less than that of the conventional double-tapped IPR. Simulation and experiment results show that the THD of input line current is less than 5%.

A Simple Harmonic Reduction Method in Multipulse Rectifier Using Passive Devices

A fundamental frequency-sorting algorithm with staircase modulation is proposed to balance the floating capacitors for modular multilevel converters. The driving pulses are assigned to the submodules at every fundamental period according to their charging capabilities for the capacitors. The charging capabilities of the driving pulses can be evaluated by sorting the voltage increments of the capacitors or derived from the symmetrical characteristic of the curve between the voltage increments and the pulse numbers. With this method, all the power devices switch only once per fundamental period, which is suitable for high-power applications. Meanwhile, the sorting frequency decreases to the fundamental frequency. Hence, a large number of calculation resources can be saved. Moreover, it does not need to measure the arm currents so that several current sensors can be saved and the communication protocol between the central and local controllers can be simplified. At last, a three-phase simulation platform with 20 submodules per arm and a down-scaled experimental prototype with eight submodules in each arm are built to validate the proposed voltage-balancing method.

A Capacitor Voltage Balancing Method With Fundamental Sorting Frequency for Modular Multilevel Converters Under Staircase Modulation

This paper presents a power supply for high power and high current DC applications. Presently thyristor rectifiers along with passive filters are used in these applications, which suffer from poor input power factor and input current quality problems. The proposed power supply utilizes a modular multilevel rectifier and inverter, medium-frequency transformer and diode rectifier to convert medium-voltage AC to low-voltage DC via a medium-frequency AC link. Configuration provides unique advantages like high efficiency, high input power factor, good input current quality and controlled output current over the full operating range. Circuit configuration, design, control and performance of the proposed system are discussed in detail. Simulation results are presented to verify the performance and effectiveness of the system.

A modular multilevel converter based high-power high-current power supply

In order to design a high-density, high-power transformerless on-board charger, e.g. the Vienna Rectifier (VR) would be a suitable topology as three-phase PFC-front end. However, limits regarding residual currents in conjunction with the given parasitic capacitances of the traction battery and with the explicit y-capacitors connecting within specific loads the high-voltage DC-system (HV-system) to ground complicate the use of a conventional Vienna Rectifier (VR). Therefore, a modified configuration is proposed which changes however the operation mode significantly leading to a low common-mode (CM) noise. The paper explains those changes analytically and validates them by simulations and measurements on a hardware prototype of 11 kW. Moreover, this prototype is used to compare a conventional VR with the proposed four-wire topology, denoted here also as ZeroCM-topology. Especially under low-load conditions, the proposed ZeroCM-variant offers significant benefits.

Comparison of Unidirectional Three- and Four-Wire-Based Boost PFC-Rectifier Topologies for Non-Isolated Three-Phase EV On-Board Chargers Under Common-Mode Aspects

This paper presents a 1MW, 12-pulse thyristor rectifier with passive filter and DSTATCOM for low voltage, high current industrial dc loads. The considered process act (electrically) as a current controlled, variable voltage load. Moreover the load characteristic varies extensively with number of hours of operation. Variable compensation capabilities are required to provide harmonic and reactive power compensation for such kind of loads. A Distribution Static Compensator (DSTATCOM) is used to provide variable reactive power compensation. Along with it an 11th harmonic passive filter with substantial amount of reactive power support is provided to reduce required rating of DSTATCOM. Design and control of system are carried out such that input power factor remains greater than 0.98 and THD remains below 5%. Simulation results are presented to verify the effectiveness of the system.

Analysis, design and control of 1MW, high power factor and high current rectifier system

In this paper, a commonly reported single-phase four-switch AC chopper topology is compared with a six-switch topology in terms of the total harmonic distortion (THD) of the input current, power factor (PF), commutation behavior, robustness and efficiency Working principles of both topologies are presented along with simulation results Based on a comparison of the findings, the four-switch topology is found to be better choice for the given application Thus, the implementation of a four-switch topology is carried out at a power level of 10 kW Experimental evaluation is carried out in order to verify the suitability of the circuit for the intended application The experimental setup validates the findings of the simulations Thus, the proposed approach is a practical way to improve input current THD and PF compared to thyristor choppers

Comparison of PWM AC chopper topologies

Handle everyday research tasks with reliable, citation-backed results

Your personal Research Agent to handle research tasks with citation-backed results

Popular Tasks used by Researchers

How can I help with your research?

Meet SciSpace

Get more enhanced response by uploading the PDFs you want me to reference.

No relevant PDFs in your library

SciSpace is the AI research assistant for academics. Run systematic literature reviews on 280M+ papers, and write papers with cited sources. Trusted by 1M+ students, PhDs & researchers.

SciSpace | AI for Research

Analyze PDFs

Code & Manuscripts

Funding & Grants

Literature & Patents

Medical & Clinical Data

Systematic Review

Visualize & Present

Web & Data

Build a Google Scholar-like website for your research.

Build a website

Create charts and images for your research

Create a Chart

Write a paper for submission to a journal

Draft a manuscript

Patent Search

Design eye-catching scientific posters in minutes.

Scientific Poster Generation

Systematic Literature Review

One task is running at the moment. Your messages will be shown right after.

Drag and drop or click here to browse

Loved by <highlight>1 million+</highlight> researchers

Extract a list of specific topics and their sources from unstructured text

Topics

Compare and analyze relevant papers that matches with your search

Papers

Get insights from PDFs and bookmarked papers from your library

My library

Recent searches

Try searching for:

Catch AI-generated content in scholarly and non-scholarly content

{ai} Detector

Ai Writer

Get PDF Summaries, highlighted text explanations 

Chat with PDF

Effortlessly create in-text citations and bibliographies in APA and 2,500 other formats

Citation generator

Get explanations, summaries, and answers on academic papers

Ease up your research workflow with {scispace}'s cohort of exciting AI tools

Elevate your academic writing skills and convey your ideas the way you want

Paraphraser

Explore our range of reading and writing tools

Your file is being prepared and should be ready in a few minutes. If it's a large file, it might take a bit longer. You can close this window, and we'll email you the file when it's done.

You have reached a maximum limit of <strong>{limit}</strong> columns in the table. Remove at least <strong>1</strong> column to add or create another one.

Peter Wallmeier

Author Tools

Chat about Author