by Daming Zhang  and Xiuhui Tang

Received: 01 September 2023;  Published: 29 November 2023;  doi: 10.21926/jept.2304039

Large-scale autonomous microgrids have potential application values as they can increase renewable energy penetration level without compromising the stability of the existing large power systems. Before their widespread implementation, critical issues like stability analysis etc need to be solved. This paper analyses the stability in an autonomous microgrid operated at constant frequency with the consideration of reactive power balance. Difference equations of reactive power for the grid-forming generator are const [...]

by Hunter Heineman  , Omran Omar  , Benjamin Rippel  , Ryan Keeley  , Michael Mehan  , Surendra Gupta  and Gerald A. Takacs

Received: 21 August 2022;  Published: 06 December 2022;  doi: 10.21926/jept.2204040

Ozone was reacted with the aromatic membrane polyetheretherketone (PEEK) to form oxidized functional groups on the surface to enhance the attraction and transport of protons in fuel cells. Ozonation of unsaturated C-C sp2 bonds in PEEK formed a primary ozonide which dissociated to primarily produce O=C-O/O=C-OH moieties, and the root mean squared roughness factor (Rq) decreased from 7.4 nm, for the untreated sample, down to 3.1 nm. The oxidation of the surface and decrease in surface roughness made the surface incr [...]

by Despina Vamvuka  , Stelios Sfakiotakis  and Elpida Patlaka

Received: 12 November 2024;  Published: 24 January 2025;  doi: 10.21926/jept.2501004

Independent parallel reactions (IPR) and distributed activation energy (DAEM) kinetic models were developed and compared for the combined pyrolysis-gasification of two agro-industrial waste materials. The aim was to recycle greenhouse gas carbon dioxide for mitigating emissions, to evaluate the thermal behavior, reactivity, conversion and product composition in terms of structural/chemical characteristics of the fuels, and to provide accurate kinetic parameters useful in the scaling-up of the process. The experimen [...]

by Minyang Wang  , Daming Zhang  and Liang Yuan

Received: 15 July 2024;  Published: 15 November 2024;  doi: 10.21926/jept.2404021

As the penetration level of inverter-based generators continues to increase, it becomes crucial to reduce power oscillations between inverters and synchronous generators (SG) to improve system stability. This paper uses a multimachine system as the research platform and proposes a grid separation method employing a multi-terminal back-to-back converter. The converter is designed to be placed at the point of common coupling (PCC) in the original multimachine system and can divide the original grid into multiple micr [...]

by Mahmoud F. Elmorshedy  , Abualkasim Bakeer  and Dhafer Almakhles

Received: 14 February 2023;  Published: 09 May 2023;  doi: 10.21926/jept.2302017

The special design of linear induction machines (LIMs) leads to adverse effects caused by the longitudinal and end effects. These effects make the thrust control of the LIMs most attractive because its value decreases sharply with the speed increase. Thus, finite-state model predictive control (FS-MPC) is developed to increase the performance of the LIMs. However, the variable switching frequency is the main drawback of this control. Consequently, the main objectives of this paper are to propose FS-MPC with a const [...]

by Edmund Zolnik

Received: 14 January 2022;  Published: 02 August 2022;  doi: 10.21926/jept.2203026

Monetary incentives to accelerate the transition of private vehicle fleets to zero emissions promote sustainability in the transportation sector. Clean Cars for America to incentivize transactions for new battery power vehicles is a program in furtherance of sustainable transportation goals in the United States. Unfortunately, data on transactions for new alternative fuel vehicles (AFVs) are scarce so empirical research to explore the costs and/or the benefits of such programs is also scarce. Analysis of transactio [...]

by Carlos Armenta-Déu  and Ángela Trujillo

Received: 10 October 2024;  Published: 07 March 2025;  doi: 10.21926/jept.2501005

The growing demand for energy and the need to reduce dependence on non-renewable sources have driven the research and application of sustainable technologies. In this context, an integrated solution that combines distributed energy generation from renewable sources, such as wind and hydro, with efficient management of household energy consumption is proposed. This study focuses on the hybrid renewable energy system simulation analysis designed to meet the demand of an off-grid household in a self-consumption mode. [...]

by John Konstantaras  , Christos Pagkalos  , Maria K. Koukou  , Kostas Lymperis  , Yannis Caouris  and Michail Gr. Vrachopoulos

Received: 17 April 2022;  Published: 09 June 2022;  doi: 10.21926/jept.2202021

In this study, the performance of a self-sufficient controller used for a solar-latent heat domestic hot water (DHW) production unit under real-world operating conditions was analyzed. The unit consists of a flat-plate solar collector and a latent heat storage tank. The controller is powered by a small solar panel and governs the charging and discharging of the system, ensuring maximum solar energy absorption, desired hot water temperature, and constant monitoring of the heat-storage tank’s capacity. The system is [...]

by Qin Xu  , Kang Nai  and Valery Melnikov

Received: 05 August 2022;  Published: 13 October 2022;  doi: 10.21926/jept.2204034

By using long pulses with extended dwelling time, lowered pulse repetition frequency (PRF) and reduced Nyquist velocity, the radar measurement capability can be enhanced to increase clear-air Doppler velocity data coverage (which is beneficial for radar wind analysis and data assimilation and motivated our previous study). This potential capability is further explored (beyond our previous study) by not only modifying the existing operational clear-air scan mode with a lowered PRF and reduced the Nyquist velocity (t [...]

by Rafael B. Oliva  , Andrés Zappa  , Mariano Amadio  and Guillermo Catuogno

Received: 31 October 2024;  Published: 05 May 2025;  doi: 10.21926/jept.2502009

This work addresses the main results of a test site for small wind turbines (SWTs) located in Patagonia, and the development of the measurement systems involved, including the uncertainties calculations according to applicable IEC standards. Due to market evolution for over a decade, the test systems evolved from battery-charging SWTs to grid-connected units. The test site, developed and managed by state-owned INTI (National Institute for Industrial Technology), was established in 2012 and received support from the [...]