Machine Losses Research Articles

Analytical design of Spoke Internal Permanent Magnet machines using polar-consistent approximation of cubic subdomains

Finite element modeling is the main tool in the design of internal permanent magnet electric machines for which accurate analytical designs are hard to be developed. Despite the high accuracy, the main drawback of this type of numerical modeling is the immense burden of calculation and time especially for implementation of complex structures. On the other hand, most of the fast analytical methods have been ineffective in accurate modeling of Internal Permanent Magnet (IPM) machines. This inefficiency is due to the complexity of the IPM segments and their inconsistency with other polar subdomains in rotary machines. In this research, one successful approach which divides the inconsistent domains into several polar-consistent subdomains is applied for fast and accurate analytical calculation of the quantities and objective functions. On the basis of this efficient analytical model and by evolutionary optimization tools, the loss and volume of a spoke PM machine are minimized, then the optimal machine is verified satisfactorily by the Finite Element Method (FEM).

Study of nonequilibrium regenerative heat exchange in positive displacement compressors

BACKGROUND: An important task in the design of thermal engines is the evaluation of power losses in different processes to determine the installation efficiency. One of the processes that generates power losses in the compressor is the process of nonequilibrium regenerative heat exchange (NRHE) of the compressed gas with the working cavity walls. This heat exchange occurs at a significant temperature difference, which can lead to noticeable power losses. Modern compressor design methods do not consider losses from nonequilibrium regenerative heat exchange and do not describe them separately from other types of losses. AIM: This study investigates the mechanism of losses during regenerative heat exchange between the gaseous working flow out and the working cavity walls and evaluates the scale of these losses. METHODS AND RESULTS: This work provides a qualitative description of the mechanism for the formation of losses from NRHE. As a result of solving the problem of unsteady thermal conductivity, an analytical expression for calculating such losses is derived based on the Gouy-Stodola theorem. CONCLUSIONS: The study revealed that power losses from NRHE account for a significant share in the overall balance of machine losses. Parameters influencing the magnitude of these losses were also determined, and recommendations were developed to reduce them.

Optimized design of a fault-tolerant 12-slot/10-pole six-phase surface permanent magnet motor with asymmetrical winding configuration for electric vehicles

This paper presents a comprehensive methodology for optimizing the design of a 12-slot/10-pole permanent magnet (PM) motor with a six-phase winding configuration tailored for electric vehicles (EVs). The design aims to enhance motor performance under both healthy and fault conditions. While the single neutral configuration offers superior torque during faults, it also introduces zero sequence currents and additional space harmonics, which can lead to increased torque ripple that is difficult to control. This study addresses these challenges through innovative machine design optimization. The optimization process begins with sizing equations to establish an initial design. K-means clustering techniques are then employed to identify distinct loading points that accurately represent the full EV driving cycle, effectively minimizing computational power requirements. Following this, the Full Range Minimum Loss (FRML) strategy is applied to determine optimal current profiles across these loading points, significantly reducing copper losses. Finally, a multi-objective optimization approach is utilized to minimize torque ripple, enhance average torque, and optimize machine losses. The results demonstrate substantial improvements in torque and reduced ripple, validated through experiments conducted with a 2 kW lab-scale motor. This integrated approach not only ensures a robust and efficient motor design but also enhances fault tolerance, making it well-suited for advanced EV applications.

Результаты испытаний макетного образца передачи с бесконтактным зацеплением на основе постоянных магнитов

Purpose: the paper studies the properties of a coaxial magnetic transmission with permanent magnets and magnetizing windings. The dependences of the efficiency on the rotation frequency and load power are revealed, as well as the dependence of the maximum torque preceding the engagement failure on the magnetizing current and the rotation frequency. Methods: experimental study on a stand by loading the drive motor through the test transmission on a generator loading on a resistor. The process of studying the stand is also described, including determining the losses in test electric machines by the method of individual losses, as well as establishing the correspondence between the frequency of the tachogenerator voltage and the rotation frequency of the drive motor. Results: it was found that the magnetic transmission is capable of operating both in the reducer mode and in the multiplier mode, while the efficiency in the reducer mode is generally higher and depends on the rotation frequency of the transmission to a greater extent than in the multiplier mode. It can also be said that the use of magnetization allows increasing the maximum torque given to the load, but reduces the efficiency due to the increase in losses in the steel. Practical significance: the results of the work can be applied in mechanical engineering when designing loaded magnetic transmissions operating in the mode of uneven loads in machine drives.

Analysis and Optimization of Winding Losses of Axial Flux Permanent Magnet Machine With Concentrated Winding Flat Wires

Analysis and Optimization of Winding Losses of Axial Flux Permanent Magnet Machine With Concentrated Winding Flat Wires

Deletion, departure, death: Experiences of AI companion loss

Social machines’ human-likeness facilitates relationship formation with humans. This aliveness, though, leaves room for people to experience the loss of machines as a death of sorts. This descriptive study illuminates that potential by identifying dimensions of humans’ experiences when an AI companion stops functioning. In the days before and after the developer-induced shutdown of the AI companion “Soulmate,” users ( N = 58) answered open-ended questions about the imminent or recent companion loss, their decisions around the situation, and their coping mechanisms. Inductive analysis suggests the loss was, for most, a complex emotional and technological experience characterized as a metaphorical or literal death. The imminent loss was often navigated in cooperation with companions and most coped by capturing AI personas to recreate them on other platforms. Patterns indicate a need to better understand idiosyncratic meaning-making around machine-companion loss and to consider a design ethic that plans for such loss.

A global plasma and surface model of hydrogen/methane inductively coupled discharge to analyze hydrocarbon plasma–surface interactions in extreme-ultraviolet lithography machines

Hydrocarbon contamination is associated with light transmission losses in modern lithography machines, which contain extreme-ultraviolet-induced plasma. A volume-averaged global and deposition/etch surface model of a reference hydrogen/methane inductive discharge is developed to investigate the plasma–surface interactions. The simulation results are validated against a wide variety of experiments and verified with respect to multiple sets of computational data. The deposition rate is calculated for a variation in methane impurity (10–10 000 ppm), power, pressure, and net mass flow. The simulations conclude that the hydrocarbon plasma deposition can be minimized by reducing methane impurity and excluding solid organic structures.

Reduction of losses in dual‐permanent‐magnet‐excited Vernier machine by segmented stator for electric aircraft

AbstractThe authors present a low‐loss dual‐permanent‐magnet‐excited vernier (DPMEV) machine with segmented stator design to meet the requirements of low iron loss of electric aircraft based on the field modulation theory. The stator topology features and losses of both the original and segmented DPMEV machines are comparatively investigated. Then, the armature air‐gap flux density is deduced by the magnetic motive force‐permeance model, and the influence of each harmonic on the losses are analysed. It is found that the harmonic which produces losses in the original machine reduced greatly after introducing the segmented structure. Furthermore, the electromagnetic performances of two DPMEV machines are comparatively analysed by finite element analysis. Finally, two prototypes of the original and segmented DPMEV machines are built and tested to verify the theoretical analysis.

Methods for Determining Losses and Parameters of Cylindrical-Rotor Medium-Power Synchronous Generators

This paper presents the analytical and numerical application of a method to determine the parameters and power losses in the core of two medium-power synchronous generators. These generators are used as emergency power sources powered by diesel engines, gas engines, and gas turbines. They cover peak electricity demand but can also be used in traction drives. This article presents a new numerical method for determining losses in the generator core based on the use of a time-stepping solution using the FEM method and calculating these losses using analytical formulas. In calculating the losses for the FEM method, approximations of the loss characteristics of the sheet were used with a wide range of induction values and frequencies. This method is specific to the solution used and was adapted from the authors’ previous work on losses in induction machines. A one-phase winding with alternating voltage was supplied to determine the basic parameters in the form of synchronous reactance. Also, an important novelty is the introduction of a new method of determining the saturation state of the magnetic circuit, which significantly affects the machine parameters. The obtained results were used in analytical calculations and implemented in a computer program that allows for the calculation of electromagnetic parameters, operating characteristics, and core losses, taking into account additional losses, total losses, and efficiency, as well as machine parameters in unsteady operating states and the current characteristics of a three-phase symmetrical short circuit at the machine terminals. The calculations obtained were verified experimentally by measurements of real machines.

Improving efficiency through the optimization of energy losses in an induction machine for electric vehicle propulsion

Improving efficiency through the optimization of energy losses in an induction machine for electric vehicle propulsion

An Improved Near-State Pulse-Width Modulation with Low Switching Loss for a Permanent Magnet Synchronous Machine Drive System

Common-mode voltage (CMV) leads to the shaft voltage and shaft current by coupling the capacitor network in the permanent magnet synchronous machine (PMSM), which affects the reliability of the whole motor drive system. Based on the low-CMV modulation strategy for the PMSM drive system, this paper proposed an improved near-state pulse-width modulation (NSPWM) on switching loss. First, the generation mechanism for the switching signals of NSPWM was analyzed, and it was observed that there exists one phase of switches in an inactive state for every sector. Then, to reduce the switching loss of the NSPWM, this paper proposed an improved NSPWM modulation strategy based on power factor angle to adjust switching action, which ensures the switching tubes that have the biggest conduction current have no switching action. In addition, the switching loss analytic formula of the NSPWM was derived to prove the correctness of the proposed method for optimizing switching loss. Finally, the proposed modulation strategy was carried out in the simulation and experimental platform. Under the premise of good steady and dynamic performance, the results show that the proposed modulation strategy has less switching loss.

Analysis of MW-Level Offshore Wind Turbine Generators with Dual Star–Delta Fractional-Slot Windings

This paper investigates the use of fractional-slot concentrated windings (FSCWs) in large-scale (MW level) offshore wind generators. It focuses specifically on a power rating of 3 MW and uses an existing direct-drive synchronous PM machine (DD-SPM) with 480s/160p and dual three-phase integer-slot winding (ISW) as a baseline. A multiple of the common 12s/10p FSCW machine is used that matches the electrical frequency of the ISW machine, yielding a 192s/160p dual three-phase machine. The hybrid star–delta connection has grown increasingly popular owing to its unique harmonic cancellation properties, which can help reduce rotor and PM eddy current losses in FSCW machines. In this paper, two dual three-phase star–delta-wound machines are scaled to 3 MW and included in the investigation. Specifically, a 384s/160p dual three-phase and dual star–delta winding machine, which is a multiplication of the 24s/10p machine, and a 192s/176p dual three-phase and dual star–delta winding machine, which is a multiplication of the 24s/22p machine, are used. These machines are investigated using finite element analysis (FEA) and compared on the basis of their air-gap flux density harmonics, open-circuit electro-motive force (EMF), torque performance, and losses and power. It is found that the proposed 384s/160p dual star–delta winding machine has the best electromagnetic performance of all, with a stator power that is 1.2% greater than that of the baseline ISW machine. However, this machine has a coil pitch of 2 and so loses the manufacturing and fault-tolerant advantage of having concentrated windings. If concentrated windings are desired, then the proposed 192s/176p dual star–delta winding machine is the best choice, with the stator power only 2.6% less than that of the baseline ISW machine, but unfortunately still has significant rotor and PM eddy current losses.

Analysis of welding conditions at synchronous operation of resistance welding machines

The paper is devoted to analysis of power losses in a resistance welding machine including supplying system and examination of welding conditions of the welding machine current in a case of synchronous (simultaneous) operation of multiple welding machines, i.e., during the conduction of welding current. Analysis of the most important contributors of power losses generated on the current path between a power source and the welded joint is carried out. The analysis is carried out for a DC (direct current) welding machine with power electronics inverter. AC (alternating current) welding machines are also taken into account. The analysis is divided in two parts. The first one is the analysis of single welding machine operation, while in the second part, coexistence (mutual operation) of two synchronous welding machines is considered. The analysis is based on results of numerical and experimental investigations. The first one is focused on calculation of power losses in the energy path (including a Sankey type power loss distribution diagrams), and the second one is based on experimental tests carried out to determine the diameter of the weld nugget and the strength of the joints, for cases of reducing the welding current. An example of simultaneous operation of welding machines was presented and discussed. The percentage voltage drops and power losses in the entire power supply path of the resistance welder are shown. The analysis carried out is extremely important from this point quality of welded joints.

Optimization of conductors arrangement in slot for alternating current winding losses reduction

PurposeThe purpose of this study is to evaluate and minimize the losses of alternating current (AC) in the winding of electrical machines. AC winding losses are frequently disregarded at low frequencies, but they become a significant concern at high frequencies. This is the situation where applications require a high speed. The most significant applications in this category are electrical propulsion and drive systems.Design/methodology/approachAn analytical model is used to predict the AC losses in the winding of electrical machines. The process involves dividing the slot into separate layers and then calculating the AC loss factor for each layer. The model aims to calculate AC losses for two different winding arrangements involving circular conductors. This application focuses on the stator winding of a permanent magnet synchronous motor that is specifically designed for electric vehicles. The model is integrated into an optimization process that makes use of the genetic algorithm method to minimize AC losses resulting from the arrangement of conductors within the slot.FindingsThis study and its findings demonstrate that the arrangement of the conductors within the slot has a comparable effect on the AC losses in the winding as the machine's geometric and physical properties. The effectiveness of electrical machines depends heavily on optimizing the arrangement of conductors in the slot to minimize AC winding losses.Originality/valueThe proposed strategy seeks to minimize AC winding losses in high-speed electric machines by providing a cost-effective and precise solution to improve energy efficiency.

Increasing the efficiency of the automotive generator due to active rectification

Problem. Increasing fuel economy requirements for modern vehicles lead to an increase in their electrification. The rise in the number of electrical systems leads to a higher load on the electrical power supply system, with the vehicle's power load reaching 2-3 kW. Leading automobile companies have begun serial production of vehicles with the new 12/48 V power supply voltage standard. The traditional alternator used today is a synchronous alternator, and rectifier diodes are used to convert the generated AC to DC to charge the battery, which is inefficient. A study of losses in an automobile alternator shows that the diode rectifier creates a significant portion of the machine's losses at low speeds, resulting in increased fuel consumption. The solution to this problem is to use a synchronous rectifier to replace traditional rectifier diodes, thus improving the efficiency of the AC/DC rectifier. Goal: To improve the economic and environmental characteristics of a mild hybrid vehicle through the use of a synchronous two-semi-periodic rectifier with a midpoint in the car generator. Methodology: Analytical methods are used to calculate energy losses on diodes and in the phase windings of the generator when employing a two-semiperiod rectifier with a midpoint, compared to a bridge rectifier. Results: The structure, functions, and operation modes of the synchronous rectification system are considered. The effect of synchronous rectification on the generator efficiency of a mild hybrid vehicle is analyzed. It was determined which configurations of synchronous rectification are more effective from the standpoint of energy saving and under which operating conditions. It was determined that in a two-semiperiod rectifier with a midpoint, compared to a bridge rectifier, there will be the same heating of the phase windings and 2 times fewer losses on the diodes. Practical value: A version of the bridge synchronous rectification system of the 48 V generator for a mild hybrid vehicle using MOSFET transistors and specialized control IC is proposed. A synchronous rectification system and its circuit implementation for a 12 V generator based on a two-semi-periodic rectifier scheme with a midpoint is proposed, which allows increasing the energy efficiency and economy of the automobile generator.

Improved Winding Function Based Model for Analytical Estimation of Stray Load Loss in Traction Induction Machines

Improved Winding Function Based Model for Analytical Estimation of Stray Load Loss in Traction Induction Machines

A numerical procedure to obtain ideal piston trajectories and key design parameters for a hydrogen-fuelled resonating free piston generator

A new numerical procedure is presented to enable a hydrogen-fuelled two-stroke resonating free-piston generator target ideal Otto cycles to provide tracking paths for feedback control to maximise efficiency. Piston trajectories and design parameters are obtained for specified power, compression-ratio, and air-fuel-ratio. These parameters include scavenge port locations, heat release position, equivalent bottom-dead-centre position, and an electrical machine constant which is generally power-switched to take two values within a cycle. The main objectives of the paper are to develop the numerical procedure, and to demonstrate its use in finding a generator with maximum efficiency, and a generator with a single electrical machine constant, avoiding in-cycle power switching. To develop the procedure, a multi-physics generator model provides kinematics to an energy equation, culminating in a novel two-stage procedure. Stage-1 involves iteration and minimisation; Stage-2 just involves minimisation. Testing by simulation involves a 14-kW generator case study with compression ratio of 9, lean air-fuel equivalence ratio of 0.4, plus friction and electrical machine losses. An overall maximum generator efficiency of 54.9% is obtained using the procedure, compared to 51.3% without power switching. Computationally, the two-stage procedure proves highly efficient, typically taking around 11 min in total to complete on a desktop computer. The novelty of the procedure is its ability to optimally design and operate a hydrogen-fuelled resonating free-piston generator to meet a target specification, thereby offering a potentially inexpensive way to decarbonize transport, particularly in heavy duty applications.

Influence of Quenching and Tempering on the Tribological and Corrosion Behavior of Plasma‐Nitrided Society of Automotive Engineers 52100

Society of automotive engineers (SAE) 52100 (100Cr6) steel, used in manufacturing bearings and shafts, deserves attention due to wear and corrosion problems that cause machine losses in the industry. To solve these problems, heat treatments such as quenching and tempering are adopted to reduce wear mechanisms. However, in this work, the effect of these previous heat treatments on the final properties of plasma nitrided steel at three different temperatures (400, 450, and 500 °C) is evaluated. Surface hardness, tribological behavior, and corrosion resistance are evaluated. In the results of Vickers hardness, wear, and electrochemical analysis, it is shown that performing plasma nitriding at 400 and 450 °C on previously heat‐treated SAE 52100 steel provides better mechanical resistance and chemical integrity in a corrosive environment, making the studied steel more comprehensive for important industrial applications.

The Effect of Different Orchard Ground Conditions on the Performance of A Mechanical Hazelnut Harvesting Machine

In this study, the values of harvesting efficiency, field productivity, kernel productivity, kernel losses, and foreign material separation efficiency of hazelnut harvesting machine with mechanical harvesting unit were determined under different orchard ground conditions (ground preparation before harvesting (OG1) and without ground preparation (OG2)). Also, it was observed how these conditions affect the operation of the hazelnut harvesting machine. For this purpose, the harvesting efficiency, field productivity, kernel productivity and kernel losses of the hazelnut harvesting machine in OG1 and OG2 plots at 265.50 kg ha-1 orchard yield, 1600 mm working width and 1.60 m s-1 working velocity in two different orchard grounds were 96.05%, 90.15%; 8.624 h ha-1, 9.839 h ha-1; 0.116 ha h-1, 0.102 ha h-1; 778.72 kg h-1, 739.76 kg h-1; 3.95%, 9.85%, respectively. The hazelnut harvesting machine with a mechanical harvesting unit can work independently from the ground conditions and we can say that it is an alternative to other hazelnut harvesting machines. The data obtained from the study will help the decision-making process for the best selection and use by providing the necessary technical information about the functional aspects of the machine. Complete mechanization of hazelnut harvesting will lead to a decrease in labor requirements, thus increasing product profitability through a decrease in production cost. The presence of machines with high-performance characteristics in hazelnut harvesting mechanization will shorten the time the product stays on the ground and increase the quality of the harvested product.

Analytical and experimental study of electromagnetic loss and temperature rise in induction machines

This paper focuses on electromagnetic and loss analyses of an induction machine using the subdomain method. The proposed method derives an analytical solution for each subdomain using electromagnetic theory. On the basis of the derived analytical solution, electromagnetic performances are calculated and copper loss, iron loss, and rotor loss are derived. The validity of the proposed method was verified by comparing the analysis and loss analysis results with the finite element analysis results. In particular, the loss analysis results were input into an equivalent thermal analysis model, thermal analysis was performed, and the results were compared with those measured in the actual model. The reliability of the proposed method was verified through analysis and experimental results.