The Design and Application of Power Electronics Transformers

Dear Colleagues,

A power electronic transformer (PET), also called a solid-state transformer (SST), performs the tasks of a conventional transformer by means of power electronic converters and medium-frequency or high-frequency transformers. PETs consist of several power converters, a rectifier (AC/DC), different types of DC/DC power converters, and DC/AC inverters that must be joined together to accomplish the specific AC/DC/AC conversion task. PETs can, hence, be considered different from conventional copper-and-iron-based power transformers. From a design and implementation point of view, a PET is more complex than a conventional transformer working at a utility frequency. It can, however, be smaller and lighter, and it can be digitally controlled.

The recent topology of PETs is also based on a modular multilevel converter (MMC). An MMC can be suitable for medium- or high-voltage power electronics and is an increasingly important technology for industrial and traction applications and as a regenerative energy source. In response to the growing industry demand for more powerful and flexible devices, PETs are able to provide ancillary services, such as voltage and power flow regulations (UPFC), Var compensation (using a static Var compensator, SVC), load power factor correction, and power quality improvements such as the elimination of voltage sag and swell and the reduction in harmonics and voltage flicker on the load side. In transportation traction chains, PETs have received increasing attention, since low-frequency transformers are heavy, and PETs would offer a way to reduce the space and weight taken up by traction chains. In silicon (Si) technology, PETs could replace traditional electric transformers, implying that the mass reduction in silicon carbide (SiC) technology could be even larger.

This Special Issue is focused on PETs; however, scientific contributions covering related topics are also encouraged. Broadly speaking, power electronics (PEs) holds the key to bridging renewable DC resources, such as solar photovoltaic systems, with the AC grid. To comply with the grid codes at the point of common coupling (PCC), it is necessary to incorporate supplementary components, such as a static synchronous compensator (STATCOM) and an energy storage system (ESS). To combine the functionalities of both a STATCOM and an ESS into a unified system, it is possible to install a single system called an E-STATCOM. PEs also offers avenues for enhancing the control and efficiency of AC electricity generation, a factor of critical importance for power sources such as wind turbines and hydroelectric plants.

High-voltage direct current (HVDC) technology has ushered in an era of remarkably efficient, long-range, and fully controllable power transmission. This innovation not only facilitates the integration of offshore wind power generation but also fosters cross-border interconnections, thereby stimulating an increased exchange of energy and cooperation among nations. In addressing contemporary power quality concerns, flexible alternating current transmission systems (FACTSs) have become indispensable tools. These systems play a pivotal role in resolving issues that emerge due to the dynamic nature of power flows, ensuring that existing infrastructure remains robust even in the context of reduced grid resilience. PEs also enables solutions such as battery energy storage systems (BESSs), pumped hydro storage, hydrogen production, and the conversion back into electricity.

We particularly invite submissions related to rectifiers, inverters, and DC/DC converters. Articles on a range of topics, such as control circuits, microcontrollers, semiconductor manufacturing, capacitors, supercapacitors, and magnetic devices, will be considered for inclusion.

Yours faithfully,

Dr. Michele De Santis
Dr. Sasa Sladic
Guest Editors

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• power electronics transformer
• power electronics
• modular multilevel converter
• ancillary services, power flow, transmission and distribution grids