scholarly journals Solid-State Transformers: Fundamentals, Topologies, Applications, and Future Challenges

2021 ◽  
Vol 14 (1) ◽  
pp. 319
Author(s):  
Saniya Khan ◽  
Khaliqur Rahman ◽  
Mohd Tariq ◽  
Salman Hameed ◽  
Basem Alamri ◽  
...  

Solid-state transformers (SSTs) have emerged as a superior alternative to conventional transformers and are regarded as the building block of the future smart grid. They incorporate power electronics circuitry and high-frequency operation, which allows high controllability and enables bi-directional power flow, overcoming the limitations of conventional transformers. This paper presents a detailed analysis of the solid-state transformer, expounding the fundamentals, converter topologies, applications, and future challenges of the SST in a systematic manner. The paper discusses the necessity of improved replacement of the low-frequency transformers (LFTs) and presents the configuration of SST. It presents SST fundamentals in individual stages and explores its origin and evolution. The basic topologies, their specifications, and control strategies are also described. The applications of SST as a replacement of LFTs are discussed along with recent applications. The future challenges for real-time implementation of SSTs are explored, and research directions are proposed.

Author(s):  
R. Vijayaraghavan ◽  
Viswanathan Naveenkumar ◽  
B. S. Pradeep Nag ◽  
K. Porteen

The emerging coronaviral infection named as COVID-19 was officially declared as pandemic on 11, March 2020 by WHO. It has so far been reported from 215 countries or territories affecting about twenty seven million people infected globally. The novel attributes on COVID-19 with sporadic reports on animal, alarms the future chances of animal mediated COVID-19 transmission. Despite lockdown in two-third of the global population, health officials are worried about the risky nature of animal infection in the current pandemic situation. The reverse zoonotic index cases in the current epidemic reported sporadically in animals through infected humans. Reported evidence suggests that bat as the major reservoir involved in COVID-19. However, still, the role of intermediate host involvement in the human COVID-19 transmission from the bat is not yet understood. It is clear that humans play a potent source of infection to transmit the disease to other humans and animals. A literature survey was conducted to a) understand the level of animal’s involvement in COVID19 pandemic and b) to measure the amount of risk of reverse zoonoses in pet animals, exposed animals etc. The epidemiological investigation suggested the need for strong surveillance on the human-animal interface area with strict advisory measures to combat this dangerous disease transmission to humans and other animals. Hence understanding animal’s role in the current pandemic is of prime importance in devising preparedness and control strategies through unique one health approach. In implementing suitable research protocol at animal-human interface along with environment by devising appropriate control strategies will reduce the future reverse zoonosis risk in the current pandemic through a holistic one health drive.


Author(s):  
Bharat Bhushan Khare ◽  
Rajeev Shankar Pathak ◽  
Sanjeev Sharma ◽  
Vinod Kumar Singh

According to future renewable electric energy distribution and management (FREEDM) system, solid state transformers play an important role in smart grid technologies. They have several advantages over conventional transformers such as bi-directional power flow, light in weight, compact size, etc. They also compensate the environmental issues which are created due to transformer oil. Because of various advantages over traditional transformer, SST is preferred widely at the present time. So in this chapter, the various architectures, needs, and applications of solid state transformers are discussed. The global market of SST has continuously improved because it has several applications and benefits.


Energies ◽  
2020 ◽  
Vol 13 (9) ◽  
pp. 2319 ◽  
Author(s):  
Mohammed Azharuddin Shamshuddin ◽  
Felix Rojas ◽  
Roberto Cardenas ◽  
Javier Pereda ◽  
Matias Diaz ◽  
...  

Increase in global energy demand and constraints from fossil fuels have encouraged a growing share of renewable energy resources in the utility grid. Accordingly, an increased penetration of direct current (DC) power sources and loads (e.g., solar photovoltaics and electric vehicles) as well as the necessity for active power flow control has been witnessed in the power distribution networks. Passive transformers are susceptible to DC offset and possess no controllability when employed in smart grids. Solid state transformers (SSTs) are identified as a potential solution to modernize and harmonize alternating current (AC) and DC electrical networks and as suitable solutions in applications such as traction, electric ships, and aerospace industry. This paper provides a complete overview on SST: concepts, topologies, classification, power converters, material selection, and key aspects for design criteria and control schemes proposed in the literature. It also proposes a simple terminology to identify and homogenize the large number of definitions and structures currently reported in the literature.


2021 ◽  
Vol 13 (16) ◽  
pp. 9423
Author(s):  
Vitor Monteiro ◽  
Julio S. Martins ◽  
João Carlos Aparício Fernandes ◽  
Joao L. Afonso

Power grids are evolving with the aim to guarantee sustainability and higher levels of power quality for universal access to electricity. More specifically, over the last two decades, power grids have been targeted for significant changes, including migration from centralized to decentralized paradigms as a corollary of intensive integration of novel electrical technologies and the availability of derived equipment. This paper addresses a review of a disruptive vision of future power grids, mainly focusing on the use of hybrid AC/DC grids and solid-state transformers technologies. Regarding hybrid AC/DC grids in particular, they are analyzed in detail in the context of unipolar and bipolar DC grids (i.e., two-wire or three-wire DC grids), as well as the different structures concerning coupled and decoupled AC configurations with low-frequency or high-frequency isolation. The contextualization of the possible configurations of solid-state transformers and the different configurations of hybrid transformers (in the perspective of offering benefits for increasing power quality in terms of currents or voltages) is also analyzed within the perspective of the smart transformers. Additionally, the paper also presents unified multi-port systems used to interface various technologies with hybrid AC/DC grids, which are also foreseen to play an important role in future power grids (e.g., the unified interface of renewable energy sources and energy storage systems), including an analysis concerning unified multi-port systems for AC or DC grids. Throughout the paper, these topics are presented and discussed in the context of future power grids. An exhaustive description of these technologies is made, covering the most relevant and recent structures and features that can be developed, as well as the challenges for the future power grids. Several scenarios are presented, encompassing the mentioned technologies, and unveiling a progressive evolution that culminates in the cooperative scope of such technologies for a disruptive vision of future power grids.


2012 ◽  
Vol 268-270 ◽  
pp. 1389-1392 ◽  
Author(s):  
You Jie Ma ◽  
Yi Li ◽  
Xue Song Zhou

This paper reviews the development of static synchronous compensator (STATCOM), and analylizes the structure of its main circuit, its working principles and control strategies. At last, this paper comes to a conclusion of technical characteristics of STATCOM and outlook of its development trends. Fast acting STATCOM, a representative of FACTS family, is a promising technology which is extensively used as state-of-the-art dynamic shunt compensator for reactive power control in transmission and distribution system. STATCOM controller employs various solid-state converter topologies, magnetics configurations, control algorithms, and switching techniques and so on. The development of STATCOM controller has been well reported in literature with its versatile application in power system. Thus deep investigation of STATCOM from the perspective of its intelligent control and the configuration of STATCOM’s main circuit is valuable.


Energies ◽  
2021 ◽  
Vol 14 (15) ◽  
pp. 4607
Author(s):  
Sebastian Stynski ◽  
Marta Grzegorczyk ◽  
Cezary Sobol ◽  
Radek Kot

Nowadays, the increasing number of nonlinear loads and renewable energy resources pose new challenges for the standard electrical grid. Conventional solutions cannot handle most of them. The weakest component in the whole system is a conventional distribution (converting medium to low AC voltage) transformer. It should not operate with unbalanced, heavily distorted voltage and cannot control power flow or compensate current harmonics. One of the promising solutions to replace the conventional transformer and thus minimize power flow and grid distortions is a power electronics device called a solid state transformer (SST). Depending on the SST topology, it can have different functionalities, and, with the proper control algorithm, it is able to compensate any power imbalances in both low voltage (LV) and medium voltage (MV) grid sides. In the case of a three energy conversion stage SST, the LV and the MV stages can be treated separately. This paper focuses on the MV-AC to the MV-DC stage only based on a star-connected cascaded H-bridge converter. In this paper, a simple control solution for such a converter enabling different current control strategies to distribute power among the phases in an MV grid in the case of voltage imbalances is proposed. Simulation and experimental results proved good performance and verified the validity of the proposed control algorithm.


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