Loss Calculation Research Articles

The Multiple Effects of RE Element Addition in Non-Oriented Silicon Steel

High-grade non-oriented silicon steel with high magnetic induction and low iron loss produced with low carbon emissions is crucial for the development of new energy and energy-saving motors. In this paper, the trace mixed rare earth (RE) elements exhibit a great potential to enhance magnetic properties in a lower carbon emission process by multiple effects on microstructure, texture, and inclusion in non-oriented silicon steel. With the trace-doped RE elements (0.004–0.030%), RE-rich precipitates preferentially form and subsequently adsorb fine inclusions below 1 μm to transform into spherical or ellipsoidal shape, which results in a significant increase in final recrystallization grain size. Moreover, the favorable λ texture (<001>//ND) is promoted while the detrimental γ texture (<111>//ND) is reduced, owing to the advantages in size and quantity of λ grains during the nucleation process. The improved magnetic properties of higher B50 and lower P15/50 are achieved with 0.004% RE at lower annealing temperature ranges. The increased λ texture is attributed to the heterogeneity in microstructure and texture as well as the grain boundary segregation of RE elements. However, a higher RE content (0.072%) leads to a deterioration in magnetic performance due to the formation of more stable RE-rich precipitates, smaller grains, and stronger γ texture. An iron loss calculation model was also proposed to guide the design of high-grade non-oriented silicon steel by incorporating the multiple effects of RE elements on grain size, recrystallization texture, and inclusion.

The validity of physical optics for microwave analysis: Accuracy through simplicity

Abstract Traditionally, the optics and microwave communities have been separated not only by the THz band but also by differences in technical knowledge, analytical and computational approaches, design processes, and measurement methodologies. In this contribution, we aim to bridge this divide by leveraging a computational asymptotic technique from optics, known as physical optics, which holds significant potential for the microwave/antenna community. This technique allows for precise microwave calculations for radiation patterns, reflection coefficients, material losses, and mutual coupling between antennas.

On the calculation of magnetic losses on non-narrow toroidal ring specimen

On the calculation of magnetic losses on non-narrow toroidal ring specimen

Reduced Order Model Coupling Frequency Domain Method for Calculation of Core Loss in SPM Machine Considering PWM Current Harmonics

Reduced Order Model Coupling Frequency Domain Method for Calculation of Core Loss in SPM Machine Considering PWM Current Harmonics

A review of theoretical loss calculation methods in medium-low voltage distribution networks

A review of theoretical loss calculation methods in medium-low voltage distribution networks

Power loss calculation for hybrid commutated converter

Power loss calculation for hybrid commutated converter

Virtual Synchronous Machine Based Direct Charging Power Control for the Two‐Stage EV Battery Charger

ABSTRACTIn this paper, a direct charging power control strategy (DCPC) based on virtual synchronous machine (VSM) technique is proposed for the two‐stage EV battery charger. In the proposed solution, the two‐stage charger involves a three‐phase full bridge‐based AC‐DC stage and a buck/boost DC‐DC stage. In control of the front‐end AC‐DC stage, the core algorithm of the traditional VSM is adopted. Nevertheless, unlike the traditional VSM‐based battery charging scheme, the DC‐bus closed‐loop in the traditional VSM algorithm is replaced by a positive feedback‐based DC power compensation loop, and meanwhile, the DC‐bus voltage is regulated by the rear stage DC‐DC converter. The proposed method can ensure stable DC‐bus voltage control and direct control of charging power. Due to the existence of power compensation control, the power balance between AC and DC terminals can be indirectly controlled without complex power losses calculation process. In addition, the autonomous AC frequency and voltage regulation abilities of the VSM technique can be inherited in the proposed method, which can appear a grid‐friendly charging pattern to ensure more stable battery charging. To verify the validity of the proposed method, systematic analysis and experiments are performed on a developed test bed.

ESTIMATION OF ELECTRICITY CONSUMPTION FOR WATER TRANSPORTATION IN PRESSURE PIPELINES AFTER THEIR REPAIR

The issues of using pipes made of different materials in water supply systems and the current situation with the technical condition of pressure pipeline transport are considered. It is noted that in order to ensure the standard service life of pipelines, it is necessary to carry out high-quality repair and restoration work using trenchless technologies and modern building materials, which include polymer pipes and flexible hoses. The object of research is a section of a dilapidated steel pipeline network of a certain thickness, diameter, depth and groundwater level above the tray. For the renovation of the pipeline, internal protective coatings are used, applied by dragging new pre-compressed polymer pipes and flexible polymer sleeves based on fiberglass. A description of trenchless technologies is presented, as well as automated programs that implement the tasks of determining the technological parameters (wall thickness of a polymer pipe and a polymer sleeve), hydraulic calculation of pressure losses depending on the degree of roughness of the pipeline walls, the inner diameter of a new two-layer pipe structure when passing a certain water flow, as well as the amount of electricity consumed for water transportation when appropriate wall thicknesses of protective coatings.

Improvement of the methodology for assessing power losses in in-plant power grids

To improve the reliability of calculations of electric power losses in low-voltage electric networks, it is necessary to take into account the influence of the main parameters of electrical equipment. In the course of the study, a structural diagram and an algorithm for determining the equivalent resistance of the section of the shop network have been proposed; the main factors determining the equivalent resistance of the circuit (resistance of low-voltage switching devices, heating temperature of conductors, ambient temperature, equipment load factor) have been identified; graphical dependencies of the change in the equivalent resistance of the radial and trunk sections of the circuit on the mean square equipment load factor and the heating temperature of conductors have been shown. The total error in estimating the equivalent resistance when calculating without taking into account the main studied parameters of equipment for radial, trunk and mixed circuits is 40 % or more. The error in the results of calculations without taking into account the resistance of contact connections of switching devices can reach 80 %. The obtained dependencies of the equivalent resistance on the main parameters of the equipment are recommended for use to improve the reliability of estimating electric power losses in intra-plant electric networks.

Efficiency Design of a Single-Phase Bidirectional Rectifier for Home Energy Management Systems

This paper examines the current state of Home Energy Management Systems (HEMSs), highlighting the key role of the single-phase bidirectional rectifier (SPBR). It provides a detailed design process for the converter used in HEMSs, with a particular focus on the bidirectional charge and discharge of high-voltage batteries. The converter’s operating conditions were determined through a comprehensive evaluation of its components, which were designed and assessed to enable accurate power loss calculations. This approach ensures proper component sizing and a clear understanding of the converter’s efficiency. A specialized electronic control circuit manages two operating modes of the converter: a boost rectifier with power factor correction (PFC) and a sinusoidal pulse width modulation (SPWM) inverter. To validate the design, a 7.4 kW prototype was developed using silicon carbide (SiC) metal oxide semiconductor field effect transistors (MOSFETs). The prototype achieved a peak efficiency of nearly 98% in both modes, with a unity power factor (PF) and total harmonic distortion (THD) below 7% at full power.

Interpretation of the Calculation Problem of Power Loss in Long-distance Transmission Lines——Starting from the Serious Errors in Calculation Methods in High School Physics Textbooks

This article points out the erroneous calculations of power loss and voltage loss in long-distance transmission lines in high school physics textbooks; Based on the basic circuit structure of long-distance power transmission, provide a series of correct functional relationships between power transmission power, line loss power and loss voltage, transmission line current and transformer ratio, load resistance, transmission line resistance, and the relationship between power supply voltage and transmission voltage, and discuss related issues based on these functional relationships.

INFLUENCE OF ANOMALOUS VALUES ON THE ACCURACY OF FORECASTING LOSSES IN DISTRIBUTION NETWORKS

The relevance of the study is determined by modern trends in managing the operation modes of distribution electrical networks using Smart Grid technologies, as well as the need to reduce the costs incurred by distribution system operators for purchasing electricity. Accurate load forecasting results at network nodes for different forecasting horizons are crucial for this purpose. Sudden changes in network topology can increase the errors in loss forecasts as a single time series, negatively impacting network management efficiency and increasing the costs of electricity procurement to cover losses. The study proposes using forecasting methods based on artificial neural networks for the calculation and prediction of electricity losses, along with a comparison of these methods. The calculations were performed using data from one of Ukraine's distribution system operators, and the test electrical network was adapted based on the CIGRE scheme for modeling electricity losses. Since the nodal load data contained gaps and anomalies, a two-step data analysis algorithm was employed using the DBSCAN clustering method for detection and correction. As a result of loss calculations based on cleaned data, the error was reduced threefold compared to calculations based on load factors. Applying data analysis methods and forecasting methods based on artificial neural networks significantly improves the accuracy of loss calculations and minimizes errors.

Hybrid mechanism‐data‐driven iron loss modelling for permanent magnet synchronous motors considering multiphysics coupling effects

AbstractThe precise calculation of iron losses in permanent magnet synchronous motors (PMSMs) remains challenging due to the interplay between various disciplines such as electromagnetism, magnetism, and thermal/mechanical dynamics. Purely mechanistic models require detailed theoretical knowledge and exact parameters, often struggling to accurately describe complex systems, while purely data‐driven methods lack interpretability, which are susceptible to data noise and outliers in feature extraction and complicated pattern recognition. Consequently, this paper aims to present a hybrid mechanism‐data‐driven model for accurately estimating the iron loss for PMSMs, considering the multiphysics coupling effects. Specifically, based on the well‐defined physical principles, an advanced iron loss analytical model that simultaneously considers mechanical stress, temperature rise, harmonics, load currents, and changing frequency is developed and then utilised to calculate numerous loss data under different operating conditions, providing a certain level of stability and reliability for prediction accuracy. Subsequently, a convolutional neural network (CNN) algorithm is employed to perform deep learning to extract features and patterns from the data. By defining a suitable loss function, the pre‐trained model was fine‐tuned and optimised using a small amount of actual data. To validate its superiority, extensive numerical and experimental analyses are conducted on the prototype. The results demonstrate that the iron losses computed using this hybrid model overcome the limitations of singular methods by effectively leveraging both theoretical knowledge and real‐world data, thus accurately accommodating various application scenarios. This integrated approach enhances the accuracy, stability, and interpretability of the model, laying a solid foundation for more specialised applications in the future.

Formulation of Mosquito Repellant Freshener Gel with China Grass as Gel Base and Lemon Grass Oil as Mosquito -Repellant

Background: Mosquitoes transmit severe diseases, including malaria, dengue, and Zika virus, necessitating effective mosquito repellents. While traditional repellents are typically sprays or lotions, these can be inconvenient and leave residues. A more convenient alternative is mosquito repellent gel, offering ease of application, lasting effects, and a more enjoyable user experience. This study focuses on a gel-based mosquito-repelling air freshener containing lemongrass oil, known for its mosquito-repelling properties and fresh citrus-like scent. Methodology: The study developed a mosquito repellent gel infused with lemongrass oil, containing active constituents such as neral, isoneral, and limonene. Sensory assessments evaluated the gel’s color and odor using 150 individual’s comments, and a hedonic test was conducted with 180 participants aged between 25-30 to assess product acceptability when applied to clothing and inanimate objects. To determine the longevity of the gel, total liquid evaporation was measured by weight loss over a four-week period, and the repellent's effectiveness was tested in a closed room. Results: Sensory assessment confirmed an acceptable color and a citrus-like odor for the gel, while the hedonic test indicated a favorable user response. Weight loss calculations demonstrated the gel's sustained presence over time. The closed-room test confirmed the gel's effectiveness in repelling mosquitoes. Conclusion: The lemongrass oil-based mosquito repellent gel is a promising alternative to traditional repellents, offering both user convenience and effective mosquito protection. Its long-lasting formula and positive sensory characteristics make it a viable option for personal and environmental use in mosquito-prone areas.

Optimization algorithm of power system line loss management using big data analytics

As global energy demand continues to rise and renewable energy sources develop rapidly, the operational efficiency and stability of power systems have emerged as primary challenges in energy management. Line loss within these systems is a critical factor for both energy efficiency and economic performance. This study leverages an electric energy data management platform that facilitates the sharing of archival information, the development of line loss calculation models, and the automated computation of electricity and line loss formulas. This ensures accurate and real-time calculations of line losses in the power grid, supporting multi-time scale analyses and providing timely, comprehensive data for effective line loss management. The platform utilizes theoretical line loss values to identify anomalies, which are categorized into five types: topological relationships, archival information, data collection, electricity metering, and consumption behavior. In response to the abnormal monthly power imbalance rate of 220 kV and 110 KV stations, and the − 3.684% exceeding the − 1% assessment limit, the designed line loss management system service layer does not need to go deep into the bottom layer of the power system. It hides the complexity of the power grid through middleware and provides data, application, and security services.

Design of Sonic Cage to attenuate noise in Mines using Sonic Crystal and Melamine Foam

Abstract Sonic crystals (SCs) are structures made of sound scatterers periodically arranged in a square or triangular lattice. Recent research on sonic crystals has demonstrated that they are efficient materials for controlling the propagation of sound. They attenuate sound in certain frequency bands due to Bragg scattering across the periodic scatterers. This range of frequencies is known as the bandgap, and it is found that sound propagation is significantly reduced in this bandgap region. Belt conveyors linked sequentially to create extensive pathways across surface mines contribute significantly to noise pollution. Typically, noise emission regulations are surpassed in areas where these conveyors operate, especially at night. The operation of belt conveyors predominantly contributes to the overall noise produced by the technological infrastructure. Hence, it is crucial to aim at decreasing their noise emissions. So, with an aim to attain elevated noise reduction, various intuitive sonic cage designs made of sonic crystals such as rigid scatterers, resonant scatterers, and multi resonant scatterers were suggested and followed by the calculation of free-field insertion loss (IL). Insertion Loss (IL) refers to the decrease in noise level at a specific location resulting from the installation of a noise control device along the sound path between the sound source and that particular location. The novelty of this work is that a class of periodic structures, called the radial sonic crystals are presented, in polar coordinates. The initial investigation shows the insertion loss of the proposed sonic cage followed by calculation of insertion loss of hybrid sonic cage design using melamine foam.

Merge Loss Calculation Method for Highly Imbalanced Data Multiclass Classification.

In real classification scenarios, the number distribution of modeling samples is usually out of proportion. Most of the existing classification methods still face challenges in comprehensive model performance for imbalanced data. In this article, a novel theoretical framework is proposed that establishes a proportion coefficient independent of the number distribution of modeling samples and a general merge loss calculation method independent of class distribution. The loss calculation method of the imbalanced problem focuses on both the global and batch sample levels. Specifically, the loss function calculation introduces the true-positive rate (TPR) and the false-positive rate (FPR) to ensure the independence and balance of loss calculation for each class. Based on this, global and local loss weight coefficients are generated from the entire dataset and batch dataset for the multiclass classification problem, and a merge weight loss function is calculated after unifying the weight coefficient scale. Furthermore, the designed loss function is applied to different neural network models and datasets. The method shows better performance on imbalanced datasets than state-of-the-art methods.

A Fast Graph-Theory-Based Algorithm for Waveform Reconstruction and Loss Calculation in Voltage Source Converters

A Fast Graph-Theory-Based Algorithm for Waveform Reconstruction and Loss Calculation in Voltage Source Converters

Calculation and measurement of motor and converter losses according to IEC 61800-9-2 ED2

Calculated and measured motor and converter losses are compared using the example of a four-pole asynchronous motor with a rated output of 110 kW, operated on a standard converter. The determination of the motor losses using the polynomial approach to describe the motor losses in the field weakening range shows a clear deviation from the measurements. To calculate the converter losses, an equation for calculating the losses in DC link chokes was shown. The polynomial approach to describe the motor losses as a function of torque and speed can also be used for converters in the constant flux range. The semi-analytical model for calculating the converter losses shows satisfactory accuracy even when the motor is operated in the field weakening range.

Calculation of heat loss for choosing a heating system in the chamber

Abstract The work studied the features of the chamber (linear dimensions, wall materials, etc.). It was revealed that the smaller the temperature difference between the environment and the air temperature inside the chamber, the lower the percentage of losses in the chamber. It has been established that due to the convective action, the hot air in the chamber predominantly rises upward. In this case, the heating elements were connected in series with each other. Power was supplied from a 220 V network through power lines. We have developed a system for monitoring the temperature inside the chamber and lamp operation in the Automation Studio 5.2 program. This system allows one to regulate the air temperature inside the chamber. Calculations were also carried out to identify the effect of temperature differences on heat loss in the chamber device. Experiments and engineering calculations have shown that in a small chamber the temperature required for seed germination cannot be achieved immediately. In the two - position closed chamber load plot, the energy consumption area is 9.4% larger than the energy consumption areas of the subsequent periodic energy consumption areas. It can be seen that heating the chamber itself requires additional electricity.