Modeling, Investigation, and Mitigation of AC Losses in IPM Machines with Hairpin Windings for EV Applications

Interior permanent magnet (IPM) machines with hairpin windings have attracted significant attention in EV applications owing to their low DC resistance and excellent thermal capabilities. In this paper, we present a comprehensive investigation of AC winding losses in IPM machines for traction applications, including analytical modeling, the influence of design parameters, and finite element (FE) verification. The proposed analytical model can predict the trends in AC winding losses for any number of bar conductors and slot/pole combinations. The results of the parametric study, obtained via the analytical model, are presented to examine the effects of key design parameters, such as conductor width and height, phase arrangement, and slot-per-pole-per-phase (SPP). To incorporate more practical issues into the analysis of IPM machines with hairpin windings, extensive FE simulations were conducted. The results indicated that the AC winding losses decrease with an increasing number of conductor layers and phases inside the slot.

Improving the Efficiency of Combination of Construction and Installation Works During the Underground Phase Under Conditions of Compacted Construction

Purpose. The urbanization development in the twenty-first century is characterized by increasing the share of multifunctional infrastructure complexes among the total volume of new and renovated construction. Projects with a developed stylobate part are characterized by significant demand, as well as placing parking lots in the space of underground floors. Such solutions make it possible to effectively use the underground space while minimizing the filling of 1–5 floors. The latter requirement is typical for the construction of historic centers, where urban restrictions regulate the maximum height of the building. The research is aimed at increasing the efficiency of works provided they are combined during the arrangement of underground phase of multifunctional complexes, which are built in the historic part of cities, in a densely built-up area and extremely limited space. Methodology. The authors reviewed the world experience in the installation of multifunctional complexes and introduced best practices in organizational and technological solutions during the development of design and technological documentation for the arrangement of underground phase of the object «New construction of a multifunctional complex with parking at 25 Volodymyra Vernadskoho Street, Dnipro.» The main construction processes of the underground phase arrangement in difficult conditions of compacted construction are considered and the critical elements during their design are determined. The technological sequence of performing related works by various contractors has been improved in order to create a time reserve and increase the reliability of the entire technological process. Findings. Organizational and technological solutions have been identified that allow combining construction and installation processes of underground phase of multifunctional complexes with a significant number of subcontractors under conditions of compacted construction, as well as under complex hydrogeological conditions or during construction in the historic buildings of the central part of cities. Originality. The authors for the first time conducted research in the field of underground phase arrangement given the location of construction equipment in the limited space of the construction site in the historic part of Dnipro and proposed a number of solutions to increase the reliability of the main construction process. Practical value. Based on the results obtained, one can correct the location of construction equipment and determine the rational sequence of construction and installation works, as well as predict the further development of construction technology. These studies can be useful during the study of disciplines «Technology of Construction Production», «Technology of special works», for the organization of scientific and practical seminars, refresher courses and more.

Caracterización dimensional con ultrasonido por arreglo de fases de discontinuidades inducidas en acero ASTM A36 mediante procesos de electroerosión y soldadura SMAW

This research evaluates the effect of the variables of Phased Array Ultrasonic Testing(PAUT) on the sectoral angular beam scans “S-Scan” and the geometric morphology of planar discontinuities such as the inclination forthe ultrasonic beam and the shape of the extremity on accuracy in measurements. The study was carried out in two stages. Duringthe first stage, eight ASTM A36 steel samples with machined notches by penetration from EDM and a welded sample with lack of penetration in a butt weld were designed and produced. In the second stage, it wasmeasured the size of the discontinuities using ultrasound inspection and different configurations of the phase arrangement. The effect of each variable and inspection setting with errors between 0.2 % and 120 % were determined by statistical analysis.

Design and Analyses of Multi-Carrier Pulse Width Modulation Techniques for Double Level Circuit Based Cascaded H-Bridge Multilevel Inverter

The paper introduces the cascaded H-Bridge multi-level inverter with single-phase arrangement connected series with full-bridge inverter and CHBMLI configuration integrated with Double level circuit is proposed to reduce the harmonic distortion to get high power quality. In the proposed configuration, a half-bridge inverter has been implemented to increase the output voltage waveform nearly twice as compared with the conventional Cascaded H-Bridge MLI. For high Power quality, the output voltage waveform with the reference of sinusoidal, the phase opposition disposition carrier arrangement has been utilized in PWM for producing gate pulse of switches. The high waveform of output voltage achieved with the less no of switches, less % THD distortion, less conduction and switching losses. The purposed symmetrical model of CHBMLI is successfully verified using MATLAB based on simulation with DLC configuration.

Electric and Magnetic Field Minimization using Optimal Phase Arrangement Techniques for MEA Overhead Power Transmission Lines

In order to minimize the electric and magnetic fields generated by Metropolitan Electricity Authority (MEA) overhead power transmission lines, the optimal phase arrangement techniques were applied for 3-circuits overhead power transmission lines (69/230 kV). In this paper, the mathematical model was formulated using a MATLAB program which validated by comparing the simulated results with the measured results where the South Thonburi power transmission lines at Rama 2 Road (outbound side) were evaluated with the same conditions. Finally, it can be concluded that the optimal phase arrangement techniques can minimize the generated electric and magnetic fields lowering than that of the limitation given by the World Health Organization.

An Optimal Phase Arrangement of Distribution Transformers under Risk Assessment

This paper presents a phase arrangement procedure for distribution transformers to improve system unbalance and voltage profile of distribution systems, while considering the location and uncertainties of the wind turbine (WT) and photovoltaics (PV). Based on historical data, the Monte Carlo method is used to calculate the power generation value-at-risk (VAR) of WTs/PVs installed under a given level of confidence. The main target of this paper is to reduce the line loss and unbalance factor during 24-hour intervals. Assessing the various confidence levels of risk, a feasible particle swarm optimization (FPSO) is proposed to solve the optimal location of WTs/PVs installed and transformer load arrangement. A three-phase power flow with equivalent current injection (ECI) is analyzed to demonstrate the operating efficiency of the FPSO in a Taipower feeder. Simulation results will support the planner in the proper location of WTs/PVs installed to reduce system losses and maintain the voltage profile. They can also provide more risk information for handing uncertainties when the renewable energy is connected to the distribution system.

System Unbalance Analyses and Improvement for Rooftop Photovoltaic Generation Systems in Distribution Networks

This paper studies the system unbalance caused by rooftop Photovoltaic Generation Systems (PVGSs) in distribution networks and proposes an improved method. The voltage and current unbalance studies for three extreme cases considering all rooftop PVGSs being connected to one single phase and then the stochastic analyses for the integration cases of rooftop PVGSs are considered. These three extreme cases lead to severe system unbalance problems. An improving method that combines the On Load Tap Changer (OLTC) and the optimal phase arrangement of distribution transformers is proposed in this paper to mitigate the system unbalance. The OLTC-based improving method is applied first. If the system unbalance is still out of range, the optimal phase arrangement of distribution transformers is further used to mitigate the system unbalance problem. The objective function of optimal phase arrangement is to minimize the system unbalance with the constraints of voltage limits, line flow limit, etc. Test results show that the proposed method can improve the system unbalance significantly even under very extreme cases.

Photocontrollable Mixed-Valent States in Platinum-Halide Ladder Compounds

Employing a two-orbital extended Peierls–Hubbard model, we demonstrate the photomanipulation of mixed-valent states in platinum-halide ladder compounds. There are two types of interchain valence arrangements, namely in-phase and out-of-phase types. The conversion of the in-phase structure to the out-of-phase structure is induced by photoirradiation, which is accelerated with increasing light intensity, while the reverse process hardly occurs. The out-of-phase arrangement is highly stabilized in the photoexcited states by the interchain electron transfer.

Circular Formation Control of Multiagent Systems with Any Preset Phase Arrangement

This paper deals with the circular formation control problem of multiagent systems for achieving any preset phase distribution. The control problem is decomposed into two parts: the first is to drive all the agents to a circle which either needs a target or not and the other is to arrange them in positions distributed on the circle according to the preset relative phases. The first part is solved by designing a circular motion control law to push the agents to approach a rotating transformed trajectory, and the other is settled using a phase-distributed protocol to decide the agents’ positioning on the circle, where the ring topology is adopted such that each agent can only sense the relative positions of its neighboring two agents that are immediately in front of or behind it. The stability of the closed-loop system is analyzed, and the performance of the proposed controller is verified through simulations.