Applications of High-Efficiency Converters

Dear Colleagues,

In the days of the first ever global energy crisis, efficiency holds one of the key answers in relation to reducing the demand and exploitation of renewables. Power converters, nowadays, provide far more than just an interface between energy sources or demand and the grid. They provide the requested means of control and coordination that smart grids need in order to improve the quality of supply and optimization of available energy resources. Therefore, their efficient operation should not be specified only by reduced energy losses, but increased flexibility and controllability over a wide range of services to the grid and the customer or producer of energy.

In this Special Issue of Energies, authors are invited to contribute their knowledge on novel converter designs that demonstrate the aforementioned properties on known applications or known converter designs that present such properties on new applications or a combination of both. In their works, efficiency can be expressed in terms of conversion losses, but also in terms of controllability and services towards a smarter energy grid. Reviews of the state of the art of high-efficiency converters are also welcome, as long as they clearly demonstrate its applicability in specified research and development areas of smart grids.

Topics of interest for publication include, but are not limited to, efficient converters which:

• interface renewable or conventional micro-sources to the grid;
• are used by critical, non-critical, or elastic demands;
• possess increased controllability;
• provide auxiliary services to the grid (e.g., voltage support);
• provide auxiliary services to the consumers/producers of energy (e.g., power quality);
• promote grid support algorithms during faults and other disturbances.

Dr. Panagis N. Vovos
Dr. Konstantinos G. Georgakas
Dr. Georgios Dimitrakakis
Prof. Dr. Antonio T. Alexandridis
Guest Editors

Manuscript Submission Information

Manuscripts should be submitted online at www.mdpi.com by registering and logging in to this website. Once you are registered, click here to go to the submission form. Manuscripts can be submitted until the deadline. All submissions that pass pre-check are peer-reviewed. Accepted papers will be published continuously in the journal (as soon as accepted) and will be listed together on the special issue website. Research articles, review articles as well as short communications are invited. For planned papers, a title and short abstract (about 100 words) can be sent to the Editorial Office for announcement on this website.

Submitted manuscripts should not have been published previously, nor be under consideration for publication elsewhere (except conference proceedings papers). All manuscripts are thoroughly refereed through a single-blind peer-review process. A guide for authors and other relevant information for submission of manuscripts is available on the Instructions for Authors page. Energies is an international peer-reviewed open access semimonthly journal published by MDPI.

Please visit the Instructions for Authors page before submitting a manuscript. The Article Processing Charge (APC) for publication in this open access journal is 2600 CHF (Swiss Francs). Submitted papers should be well formatted and use good English. Authors may use MDPI's English editing service prior to publication or during author revisions.

• conversion efficiency
• controllability
• smart grid applications
• smart grid services
• power converters

Title: Grid Quality Services from Smart Boilers: Experimental Verification on Realistic Scenarios for Microgrids with Demand Side Management Oriented to Self-Consumption
Authors: Georgios S. Dimitrakakis; Konstantinos G. Georgakas; Evangelos S. Topalis; Panagis N. Vovos
Affiliation: Laboratory of Power Systems, Renewable and Distributed Generation, Department of Electrical and Computer Engineering, University of Patras, University Campus, 26504 Rion, Greece
Abstract: The deeper penetration of renewables in the energy mix is an intense requirement in order to reduce global carbon dioxide emissions. Along with that, new technologies rise, such as electric mobility and distributed generation in urban areas. However, the unpredictable fluctuations of energy generation from roof-installed PVs and the switching operation of their inverters, greatly aggravate the already present grid quality problems. In this paper, the Smart Boiler concept for grid quality improvement is presented. Furthermore, its experimental verification is implemented on a flexible testbed that accurately emulates several realistic scenarios for the low voltage distribution grid, under complex operating conditions. The proposed low cost electronic kit, that contains a fairly simple topology converter, with single technical requirement the connection to the internet, is used to upgrade conventional domestic boilers to smart devices. The Smart Boilers automatically regulate the local reactive power flow, helping this way to stabilize the voltage level, and also suppress the grid current harmonic content, with both services provided in a matter of seconds. The higher the active power consumed and the denser the smart boilers cluster, the wider the beneficial impact on the affected network area. While this service is provided, excess energy generated by PVs is temporarily stored as heat in the boiler tanks, given the users’ hot water consumption habits. The whole application, as a demand side management tool, proves beneficial for both the network operator and the end user, especially when net-metering is applied and self-consumption is desirable in order to achieve a Nearly Zero Energy Building.

Title: Optimizing Microgrids and Smart Grids through Advances in High-Efficiency Converters
Authors: Paul Arévalo
Affiliation: Department of Electrical Engineering, University of Jaen, 23700 EPS Linares, Jaen, Spain