Explore the vast range of titles available.

The study explores shore power supply technology based on virtual synchronous machine technology. Simulation results demonstrate that this technology not only fulfills the traditional function of shore power supply by providing electricity to docked ships but also optimizes the output characteristics of shore power, making it more compatible with ship synchronous generators. This enhances the seamless integration of shore power into ship electrical systems.

Permanent magnet synchronous motors (PMSM) have become prevalent in industry and play an essential role in managing industrial processes, automation systems, and renewable energy sources due to their superior efficiency, torque, and power density. However, because it operates like a non‐linear system with quick dynamics, variable parameters during operation, and unknown disturbances, PMSM presents challenges for machine control. Non‐linear controls are required to account for the non‐linearities of the permanent magnet synchronous machine. Recently, predictive control techniques for non‐linear multi‐variable systems have gained popularity. In this work, a novel approach to robust non‐linear generalized predictive control (RNGPC) has been developed for PMSM, with the aim of tracking the reference speed while maintaining minimum reactive power, robustness to external disturbances, and parameter uncertainties. A new finite horizon cost function is integrated, with an integral action introduced in the control law. The main advantage of this technique is that it does not require the measurement and observation of external disturbance as well as parametric uncertainties. The control strategy method has been tested in the MATLAB/Simulink environment with various operating conditions. The results showed good robustness against parameter changes and ensured fast convergence. In this work, a new approach of robust non‐linear generalized predictive controller (RNGPC) has been developed for permanent magnet synchronous motors (PMSM). The control objective is tracking the reference speed while maintaining minimum reactive power and robustness to external disturbances and parameter uncertainties.

In the article, the power oscillation problem of the virtual synchronous generator (VSG) is studied. To facilitate a solution for this problem, an optimized virtual synchronous generator (OVSG) control method in view of forward atonement is designed. Tunable variables for atonement segment changing realize the purpose of suppressing the steps of the operating system and inhibiting active power oscillation of VSG. Virtual simulation and experiment test the availability of the designed method.

Synchronous education is being integrated at various levels and capacities in distance education offering learners and facilitators a virtual web-conferencing environment where, although they may be geographically separated, they are afforded the flexibility of being virtually present in a shared real-time space. This research aims to reflect on what skills synchronous facilitators perceive as necessary for entry-level facilitators to demonstrate competence in to adequately support learners in the synchronous learning environment. Participants were interviewed based on their experience facilitating within the Adobe Connect learning environment and discussed perceived technical/operational, classroom management, communication and design/delivery competencies an entry-level facilitator must possess to foster learner success in a synchronous virtual environment. Based on the data collected, the researchers developed a competency guideline that may assist higher education organizations, leadership and educators in ensuring entry-level facilitators are prepared with the appropriate level of competence to support learners while overcoming the challenges that may arise in such a technology enhanced and dependent environment. The researchers also suggest an orientation pathway to support the entry-level synchronous facilitator with their transition into the synchronous environment.

More and more higher educational institutions invest in technology-enhanced learning spaces, which raises the question of how these environments can be shaped to be as effective as possible. A specific new learning space is the synchronous hybrid or blended learning environment in which both on-site and remote students can simultaneously attend learning activities. Given that synchronous hybrid learning is relatively new, there are few studies that have investigated its use and effectiveness. This study synthesised the best available evidence worldwide to provide an overview of the state-of-the-art of the current research regarding the benefits, challenges and current design principles to set up synchronous hybrid learning. In line with the Preferred Reporting Items for Systematic Reviews and Meta-Analyses, we included 47 studies which were analysed to respond to our research questions. One of the main findings is that existing research suggests cautious optimism about synchronous hybrid learning which creates a more flexible, engaging learning environment compared to fully online or fully on-site instruction. Yet, this new learning space has several challenges which are both pedagogical and technological in nature. To meet these challenges, several design guidelines are formulated. A final conclusion is that most of the existing literature is exploratory and qualitative in nature and has focused mostly on descriptions of students’ experiences, the organisational implementation and the technological design. Empirical studies have only begun to emerge and more research is needed into different pedagogical scenarios and their impact on student outcomes.

A synchronous homopolar motor (SHM) has a salient pole passive rotor, an excitation winding located on the stator, and no permanent magnets, which ensures high reliability and makes this type of motor a good alternative to motors traditionally used in traction drives. However, there is no comparison between SHMs and conventional brushed synchronous machines for traction applications in the literature. In this paper, the performances of a wound rotor synchronous machine (WRSM) and SHM are theoretically compared at the operating points of a 370 kW dump mining truck drive traction curve that has a 10:1 constant power range in the field weakening region. The nine-phase motors under comparison have the same outer diameter of the stator lamination. Before comparison, both motor designs are optimized using the Nelder–Mead method to minimize the semiconductor inverter rated current and the operating cycle power loss. The main advantages of the WRSM, which was designed, are reduction in stator length, smaller losses, and smaller inverter. The reduction in the total stator length was by 1.23 times taking into account the winding end parts as well. Losses were reduced by 1.21 times for the same radius of the stator lamination. Finally, the cost of power modules of the inverter was decreased by 1.4 times. SHM is more reliable since its rotor does not have an excitation winding and a diode rectifier, as in a WRSM with a brushless exciter. In addition, SHM provides lower consumption of copper, which reduces the total mass and cost of active materials. This article also introduces a new term, “inverter utilization factor”, which can be useful, more informative than motor power factor, when comparing traction drives with different types of motors.

This study shows that geostationary satellites are critical to estimate the accurate cloud feedback strength over the tropical western Pacific (TWP). Cloud feedback strength was calculated by the simultaneous relation between cloud cover and sea surface temperature (SST) over the TWP [120°E–170°E, 20°S–20°N]. During 2011–2018, the cloud cover was obtained by geostationary earth orbit satellite (GEO) and low‐level earth orbit satellite (LEO) (AGEO, ALEO), and the NOAA's all‐sky SST (To) was weighted with the clear‐sky fraction observed by GEO and LEO (TwGEO; TwLEO). The linear regression coefficients between clouds and SST are very different: −7.93%K−1 (AGEO/TwGEO), −6.94%K−1 (ALEO/TwGEO), −1.35%K−1 (AGEO/TwLEO), −0.69%K−1 (ALEO/TwLEO), −0.02 %K−1 (AGEO/To), and −0.50 %K−1 (ALEO/To). Among these, only the TwGEO values provided a valid cloud feedback signal. This is because GEO's field of view is large enough to simultaneously capture cloud cover over the entire TWP. Plain Language Summary Geostationary satellites are essential for accurately estimating cloud feedback strength over the tropical western Pacific (TWP). Cloud feedback strength is the change in cloudiness that results from a change in sea surface temperature (SST). When using data from both geostationary and low‐earth orbit satellites, the resulting cloud feedback signals are very different. This is because geostationary satellites have a large enough field of view to capture cloud cover over the entire TWP, while low‐earth orbit satellites do not. Therefore, geostationary satellites are the only reliable source of data for estimating cloud feedback strength over the TWP. This is important because cloud feedback is a major uncertainty in climate models. Key Points In the tropical western Pacific (TWP), the cloud‐sea surface temperature (SST) relation has been subject to the analysis methods with satellite observations The negative relationship is revealed only when the daily SST is weighted with the clear‐sky fraction from a geostationary satellite This disparity arises from the capability of geostationary satellites to simultaneously capture a snapshot of the entire TWP area

Synchronous motors with a field winding in the rotor, known as wound-rotor synchronous motors (WRSMs) or electrically excited synchronous motors (EESMs), are claimed to be a good alternative to induction motors and even permanent-magnet synchronous motors (PMSMs) in electric traction applications. WRSMs do not require expensive rare-earth magnets and potentially have high power and torque density, and lower inverter power and cost, especially in applications demanding a wide constant-power speed range. Designing WRSMs for electric traction imposes some challenges and requires careful analysis. This paper provides an overview of commercial WRSMs for ground electric transport over the past 40 years, a comparison of WRSMs with other types of electric motors suitable for electric traction, and an overview of optimization methods and brushless excitation technologies for such machines. The goals of this paper are to present and discuss design approaches for traction WRSMs, to benchmark WRSMs against other motor types used in ground electric transport, and to highlight the most promising WRSM topologies and design techniques.

Here or There (HOT) instruction is a blended synchronous approach that enables students from on-campus (“here”) or a remote location (“there”) to participate together in class activities in real time. The purpose of this article is to share three different cases at two universities that illustrate different implementations of HOT instruction, explain the affordances of these varied approaches, provide best practices that are common to each, and share lessons learned along the way. Readers will gain a better understanding of how to implement a range of innovative HOT approaches, and in what context(s) they might choose one approach over another. The authors’ experience indicates that sound pedagogical principles along with pragmatic considerations, such as class size, available technology, and instructor’s skills, should guide decisions regarding use of these blended synchronous approaches. Future research should look towards what impact blended synchronous environments have on student outcomes.

Grid‐forming control of direct‐drive permanent magnet synchronous generator (D‐PMSG) wind turbine is an effective method to improve the frequency stability and provide inertia support for the system. In conventional virtual synchronous generator (VSG)–based grid‐forming control, fixed inertia and droop coefficients can result in poor frequency regulation under varying frequencies, and excessive reduction in rotor speed may lead to disconnection. This study analyzes the frequency support capability of rotor kinetic energy and the speed recovery characteristics of VSG‐based D‐PMSGs. It proposes a frequency support strategy for D‐PMSG that uses Adaptive Sliding Mode Extended State Observer (ASM‐ESO) to enhance the frequency regulation capability and reduce the risk of secondary frequency drops during rotor speed recovery. A grid‐forming D‐PMSG system based on the RT‐LAB platform is adopted to conduct the proposed frequency support strategy performance evaluation.