ОПТИМАЛЬНОЕ ПРОЕКТИРОВАНИЕ БЕЗРЕДУКТОРНОЙ МАШИНЫ С ПЕРЕКЛЮЧЕНИЕМ ПОТОКА ДЛЯ ВЕТРОГЕНЕРАТОРА

The relevance of the research is caused by the increasing need for autonomous hybrid power plants using renewable sources to reduce the consumption of fossil fuels. Improving the performance and reducing the cost of gearless wind generators used in such power plants will contribute to improvement of technical and economic characteristics of the plants. The main aim of the research includes the elaboration of an effective approach for optimizing the flux switching generator for gearless wind turbines, which reduces the use of computing resources, in comparison with existing approaches; elaboration of recommendations for the design of the flux switching wind generator with permanent magnets on the stator; improving the initial design of the generator. Objects of the research are the mathematical model and the design of flux switching generator with permanent magnets on the stator. Methods: assessment and analysis of wind speed data worldwide; derivative-free optimization method; finite element method; mathematical modeling; statistical methods. Results. The multicriteria optimization of the design of a gearless wind flux switching generator was carried out. As a result, the generator efficiency was increased, its torque ripple and the rated power of the electronic converter of the wind turbine system were reduced. General recommendations regarding the geometry are obtained which can be used for designing similar flux switching generators. A method is proposed for construction of substituting profiles of the operating characteristics of wind turbines, which can be used to reduce computational effort during the optimization. The computational cost reduction using the obtained method is demonstrated using the example of replacing the original nine-point working profile of a wind turbine with a substituting two-point one. © 2020 Tomsk Polytechnic University, Publishing House. All rights reserved

Comparison of Interior Permanent Magnet and Synchronous Homopolar Motors for a Mining Dump Truck Traction Drive Operated in Wide Constant Power Speed Range

Synchronous homopolar motors (SHMs) with an excitation winding located at the stator and a toothed salient pole rotor are a good alternative to motors traditionally used in traction applications such as induction motors or interior permanent magnet synchronous motors (IPMSM). This study presents the results of a theoretical comparison between an IPMSM and an SHM in a traction application with a constant power speed range of 1:10, which is specific to the mining truck drives, and with a rated power of 370 kW. The considered IPMSM and SHM have the same number of phases, poles and stator slots, and the same outer diameter of the stator lamination. The IPMSM design is optimized using the Nelder–Mead method. The main objectives of optimization are to minimize the average losses in the operating cycle and to limit the required power of the semiconductor inverter. The performance of the optimized IPMSM is compared with the previously obtained performance of the SHM optimized by the same method. Although the average losses in the operating cycle in the compared motors are approximately equal, the losses at high speed for the IPMSM are about two times greater than at low speed with maximum torque, which means that there is a need to intensify the IPMSM cooling system and there is deterioration of reliability. The advantage of the IPMSM is the reduction in the length of the active part by 30%. The advantage of the SHM is that there is 4.6 times lower cost of active materials. In addition, the SHM is more reliable than the IPMSM, as there is no risk of overheating, demagnetization or degradation of permanent magnets over time. © 2022 by the authors. Licensee MDPI, Basel, Switzerland.Russian Science Foundation, RSF: 21-19-00696Funding: The research was performed with the support of the Russian Science Foundation grant (project № 21-19-00696)

Traction synchronous homopolar motor: Simplified computation technique and experimental validation

Synchronous homopolar motors (SHMs) have been attracting the attention of researchers for many decades. Various mathematical models of SHM have been proposed to deal with its complicated magnetic circuit. Among them, there are time-consuming 3D finite element models (FEM), equivalent circuit models neglecting some significant features of the machine design, and 2D FEM models with virtual excitation winding distorting its magnetic field picture. This paper proposes a novel 2D FEM of SHM and shows that since there are no sources of excitation in the cross-sections of the rotor and stator stacks, no virtual elements are required. This model uses the general solution of the Gauss's law for magnetism containing excitation flux. The model is based on a set of magnetostatic boundary value problems for various rotor positions. The set of boundary problems is completed with the excitation equivalent circuit. The losses in the armature and field windings and the stator and rotor magnetic cores are computed in postprocessing. All these computations are carried out for a single combination of stator and rotor stack. A symmetrization algorithm is proposed to extend the obtained results to the whole SHM. A comparison of the theoretical and experimental data for a nine-phase three-section 320 kW SHM is carried out. These SHMs were used in a mining truck with a carrying capacity of 90 tons. © 2020 Institute of Electrical and Electronics Engineers Inc.. All rights reserved.This work was supported by the Russian Science Foundation under Grant 16-19-10618

Design optimization of a traction synchronous homopolar motor

Synchronous homopolar motors (SHMs) have been attracting the attention of researchers for many decades. They are used in a variety of equipment such as aircraft and train generators, weld-ing inverters, and as traction motors. Various mathematical models of SHMs have been proposed to deal with their complicated magnetic circuit. However, mathematical techniques for optimizing SHMs have not yet been proposed. This paper discusses various aspects of the optimal design of traction SHMs, applying the one-criterion unconstrained Nelder–Mead method. The considered motor is intended for use in a mining dump truck with a carrying capacity of 90 tons. The objective function for the SHM optimization was designed to reduce/improve the following main characteristics: total motor power loss, maximum winding current, and torque ripple. One of the difficulties in optimizing SHMs is the three-dimensional structure of their magnetic core, which usually requires the use of a three-dimensional finite element model. However, in this study, an original two-dimensional finite element model of a SHM was used; it allowed the drastic reduction in the computational burden, enabling objective optimization. As a result of optimization, the total losses in the motor decreased by up to 1.16 times and the torque ripple decreased by up to 1.34 times; the maximum armature winding current in the motor mode decreased by 8%. © 2021 by the authors. Licensee MDPI, Basel, Switzerland.The research was performed with the support of the Russian Science Foundation grant (Project No. 21-19-00696)

Inverter Volt-ampere Capacity Reduction by Optimization of the Traction Synchronous Homopolar Motor

The synchronous homopolar motor (SHM) with an excitation winding on the stator and a toothed rotor is a good alternative to traction induction motors for hybrid mining trucks. The main problem in the design of the SHM electric drives is that the magnetic flux forms three-dimensional loops and, as a result, the lack of high-quality optimization methods, which leads to the need to overrate the installed power of the inverter. This article discusses the procedure and results of optimization of a commercially available 370 kW traction SHM using the Nelder–Mead method. The objective function is composed to mainly improve the following characteristics of the traction SHM: total motor power loss and maximum armature winding current. In addition, terms are introduced into the objective function to make it possible to limit the voltage, the loss in the excitation winding, and the maximum magnetic flux density in the non-laminated sections of the magnetic core. As a result of the optimization, the motor losses and the maximum current required by the motor from the inverter were significantly reduced. The achieved reduction in the maximum current allows the cost of the IGBT modules of the inverter to be reduced by 1.4 times (by $ 2295), and also allows the AC component of the DC-link current to be reduced by the same amount. © 2021 by the authors. Licensee MDPI, Basel, Switzerland.Funding: The research was performed with the support of the Russian Science Foundation grant (Project № 21-19-00696)

Indirect Efficiency Measurement Method for Line-Start Permanent Magnet Synchronous Motors

Despite the great potential and the high performance of energy-efficient line-start permanent magnet synchronous motors (LSPMSMs), their developers face a great deal of difficulties, one of which is the lack of reliable and accurate testing methods for such electrical machines. In this paper, we propose a new method for indirectly determining the efficiency of LSPMSM through the summation of individual loss components. The standard input-output method usually used for these machines is based on torque measurement, requires expensive measuring equipment, and, as a rule, has great uncertainty. Contrarily, the proposed method does not require direct measurement of torque and mechanical power on the shaft and is less sensitive to measurement uncertainties. The theoretical substantiation of the proposed method and its experimental verification using a commercially available four-pole LSPMSM with a rated power of 0.55 kW are presented. Satisfactory convergence of the experimental results obtained using the standard input-output method and using the proposed indirect method is shown. © 2022 by the authors. Licensee MDPI, Basel, Switzerland

Применение метода Нелдера–Мида для оптимизации одноименнополюсного синхронного двигателя для карьерного самосвала

The relevance of the study is in the increasing need for the use of mining dump trucks with a diesel-electric (hybrid) drive for the development of minerals. Improving the operational and cost characteristics of the electric drive of mining dump trucks helps to reduce costs in the development of minerals. The main aim of the study is to find an effective approach to optimizing a synchronous homopolar motor for driving the rear wheels of a mining dump truck, which makes it possible to solve the problem of the high demand for computing resources when simulating a three-dimensional magnetic field of the motor; develop the recommendations for the design of a synchronous homopolar motor with an excitation winding on the stator; apply the optimization to reduce power losses and maximum motor current for a given traction characteristic of the drive, and to reduce the current rating and cost of the semiconductor inverter module of the electric drive of a mining dump truck with the type of motor under consideration. Object of the research is a design of a six-pole nine-phase synchronous homopolar motor with an excitation winding on the stator with a power rating of 370 kW. Methods: derivative-free optimization method; equivalent circuit method; mathematical modeling; two-dimensional finite element method. Results. A novel approach to optimization of a synchronous homopolar motor is proposed. This approach is effective from the point of view of the accuracy of calculating the characteristics and computational costs. As a result of optimization, the motor losses and the maximum current required by the motor from the inverter have been significantly reduced. The achieved reduction of the motor current allows reducing the cost of the semiconductor modules of the inverter by 1,4 times (by 2295 United States dollars), and also allows reducing the alternating component in the current of the direct current link of the inverter by the same amount. © 2022 Tomsk Polytechnic University, Publishing House. All rights reserved.The research was performed with the support of the Russian Science Foundation grant (Project No. 21-19-00696)

СРАВНИТЕЛЬНЫЙ АНАЛИЗ ДВУХ ОДНОФАЗНЫХ ВЫСОКОСКОРОСТНЫХ МАШИН С МАГНИТАМИ НА СТАТОРЕ

Purpose. Single-phase machines with permanent magnets on the rotor are widely used in a variety of applications of a low rated power. When these machines are applied in high-speed applications, a retaining ring on the rotor core must be often used. However, it makes the assembly more complex and the high-speed machines become more expensive. On the other hand, machines with magnets on the stator still can be a valuable alternative due to their simple and reliable rotor design. In this paper the comparative study of performances of two single-phase electrical machines with magnets on the stator (flux reversal electrical machine and hybrid switched reluctance machine) is presented. The following performances have been compared: efficiency, weight, active materials cost, value of rated current of switches of the frequency converter. Methodology. Calculation of electrical machines performances using solving two-dimension boundary magnetostatics problems. Results. The theoretical comparison of the flux reversal electrical machine and the hybrid switched reluctance machine has been carried out; the comparison on specific torque and efficiency of the two aforementioned machines have been obtained. The flux reversal machine has a significantly higher efficiency and  a fewer weight. In addition, it has a lower value of rated current. On the contrary, the cost of active materials of the hybrid switched reluctance one is much less. Originality. The presented results can assist in selecting the best design alternative of electrical machines in the following applications: electrical blowers, household appliances, fans, pumps and compressors of a low rated power etc. Practical value. The comparisons results of the flux reversal electrical machine and the hybrid switched reluctance machine has been obtained for the first time.Цель. Исследование характеристик двух высокоскоростных однофазных электрических машин с магнитами на статоре (электрическая машина с переменным направлением потока и гибридная вентильно-индукторная реактивная машина): сравниваются такие характеристики как КПД, вес, стоимость активных материалов, номинальный ток элементов преобразователя частоты. Методика. Расчет характеристик электрической машины с помощью решения двухмерных краевых магнитостатических задач. Результаты. Произведено сопоставление двух типов однофазных машин с магнитами на статоре; получено расчетное сравнение характеристик однофазной электрической машины с переменным направлением потока и однофазной гибридной вентильно-индукторной реактивной машины; получены результаты сравнения массы и размеров КПД двух машин. Научная новизна. Впервые получены результаты сравнения однофазной электрической машины с переменным направлением потока и однофазной гибридной вентильно-индукторной реактивной машины. Практическое значение. Полученные результаты могут помочь при выборе лучшей конструкцией электродвигателя в рассматриваемых приложениях: электрический турбонаддув, бытовые приборы, вентиляторы, насосы и компрессоры малой мощности и т.д

СРАВНЕНИЕ ЭНЕРГОПОТРЕБЛЕНИЯ РАЗЛИЧНЫМИ ЭЛЕКТРОДВИГАТЕЛЯМИ, РАБОТАЮЩИМИ В СОСТАВЕ НАСОСНОГО АГРЕГАТА

Purpose. Comparative analysis of energy consumption of various types electric motors in fixed speed centrifugal industrial pump applications is carried out. The purpose of the analysis is to choose the most efficient motor in the considered application. It is assumed that hydraulic flow of the pump is adjusted by throttling. The rated power of the pump unit is 2.2 kW. Direct on line motors of various energy efficiency classes from various manufacturers are considered: induction motors with permanent magnets on the rotor of IE4 class and squirrel cage induction motors of IE3 and IE4 classes. Methodology. Assessment of energy consumption of the motors is carried out based on the catalogue data from manufacturers of the pump and the motors. Pump hydraulic equations, interpolation of motor catalogue data and statistical data are also used. Results. The following values have been obtained: annual and daily energy consumption of the motors and electricity cost savings comparing with the least effective motor considered. Practical value. The following practical consideration are presented based on the theoretical results: choosing the motor based only on its IE efficiency class according to IEC 60034-30-1 is not enough to ensure the minimum energy consumption of pump units with variable flow during the load cycle. In addition, the energy consumption may be higher in the case of permanent magnet motors of IE4 class in comparison with induction motors of IE4 or even IE3 class. Therefore, it is necessary to take into account efficiency of the motors at underload and it is needed to calculate the energy consumption during the actual load cycle. It should be noted, that the existing approach based on the Energy Efficiency Index (EEI) calculation does not provide information about absolute values of energy savings and cost savings, in contrast to the described approach. While choosing motors to run in the considered application it is also important to take into account that the motors with permanent magnets on the rotor have significantly higher price and very restricted starting capabilities comparing with induction motors. In addition, the production of rare earth magnets causes a significant environmental damage.Цель. Сравнительный анализ энергопотребления электродвигателей разных типов и классов энергоэффективности в электроприводе центробежного насоса мощностью 2,2 кВт системы водоснабжения с дроссельным регулированием. Сравнивались синхронные электродвигатели с прямым пуском и постоянными магнитами на роторе класса энергоэффективности IE4 и асинхронные электродвигатели классов энергоэффективности IE4 и IE3 различных производителей. Методика. Расчет энергопотребления проводился на основе данных насоса и электродвигателей, предоставляемых производителями, и включал в себя расчет энергопотребления центробежным насосом в типовом рабочем цикле, предполагающем работу с пониженными нагрузками в течение продолжительного времени. Результат. Получены расчетные данные по суточному и годовому энергопотреблению рассмотренных электродвигателей в типовом рабочем цикле насоса, годовая стоимость электроэнергии исходя из среднеевропейского тарифа, экономия в денежном выражении относительно наихудшего электродвигателя из рассмотренных. Практическое значение. Показано, что выбор электродвигателя по КПД при номинальной нагрузке, то есть фактически на основе присвоенного в соответствии со стандартом IEC 60034-30-1 класса энергоэффективности IE, не приводит к минимальному энергопотреблению центробежного насосного агрегата с переменной подачей в течение типового рабочего цикла. Также показано, что применение в насосных агрегатах с переменным расходом синхронных электродвигателей с прямым пуском и постоянными магнитами класса IE4 в ряде случаев приводит к большему энергопотреблению, чем применение асинхронных электродвигателей класса IE4, а иногда и класса IE3. Таким образом, при выборе класса энергоэффективности электродвигателя как для насосного агрегата, так и для любого другого механизма, работающего значительное время при пониженных нагрузках, следует проводить расчет энергопотребления на основании данных о типовом рабочем цикле либо экспериментальных данных. При этом существующий подход, основанный на определении индекса энергетической эффективности EEI, не дает информации об экономии электроэнергии в натуральном и стоимостном выражениях, в отличие от описанного в работе подхода. При выборе электродвигателя по принципу действия следует учитывать помимо энергопотребления, то, что синхронные электродвигатели с постоянными магнитами имеют большую стоимость, чем асинхронные электродвигатели, имеются трудности их запуска при значительном моменте инерции, а получение магнитов из редкоземельных металлов сопряжено со значительным экологическим ущербом

АНАЛИЗ ПОТРЕБЛЕНИЯ ЭЛЕКТРОЭНЕРГИИ АСИНХРОННЫМИ ДВИГАТЕЛЯМИ КЛАССОВ ЭФФЕКТИВНОСТИ IE1 И IE2 В НАСОСНОЙ УСТАНОВКЕ МОЩНОСТЬЮ 11 кВт

Purpose. Comparative analysis of energy consumption indicators of electric motors of different energy efficiency classes in an electric drive of a centrifugal pump with power of 11 kW of a water supply system with throttle regulation. Methodology. In this paper a comparison of energy consumption of 11 kW pump units with induction motors of energy efficiency classes IE1 and IE2 is presented. The induction motors are powered directly from the mains. Both considered pump configurations have the same fluid flow rate characteristic of open pump systems. The amount of water consumed by the pump is adjusted by throttling. Results. The results on the daily and annual energy consumption of the two considered pump system configurations are obtained. It is shown that the pump unit using the IE2 class motor provides the annual energy savings of 9.65 thousand rubles and the life cycle energy savings of 158 thousand rubles compared to the IE1 class motor. The payback period of the IE2 class motor is calculated, which is 5 months if a new installation is commissioned and 2 years if the motor is replaced in an operating installation. Practical value. Nowadays the countries of the Eurasian Economic Union mainly use electric motors of the lowest energy efficiency class IE1, according to the IEC 60034-30 Standard (GOST IEC 60034-30-1-2016). However, according to the decision of the Commission of the Eurasian Economic Union, since the 1st of September, 2021 all general-purpose motors shall not be less efficient than the IE2 efficiency level. Therefore, the analysis of the economic effect of replacing IE1 class motors with IE2 class motors becomes relevant for the countries of the Eurasian Union. Pump drives are one of the most important consumers of electricity. Most of the pump drives are powered directly from the mains.На сегодняшний день в странах Евразийского экономического союза в основном применяются электродвигатели низкого класса энергоэффективности IE1, согласно стандарту МЭК 60034-30 (ГОСТ МЭК 60034-30-1-2016). Однако, согласно решению комиссии Евразийского экономического союза, с 1 сентября 2021 г. значение коэффициента полезного действия двигателей не должно быть меньше значений, установленных для класса энергетической эффективности IE2. Поэтому для стран Евразийского союза актуальным становится анализ экономического эффекта от замены двигателей класса IE1 на двигатели класса IE2. В данной работе представлен сравнительный анализ показателей энергопотребления асинхронных электродвигателей классов энергоэффективности IE1 и IE2 в электроприводе центробежного насоса мощностью 11 кВт системы водоснабжения с дроссельным регулированием. Асинхронные двигатели питаются напрямую от электрической сети. Обе насосные системы имеют один и тот же график расхода жидкости, характерный для разомкнутых насосных систем. Количество расходуемой насосом воды регулируется за счет дросселирования. Получены результаты по суточному и годовому энергопотреблению двух рассмотренных конфигураций насосной системы. Показано что система, где применяется асинхронный двигатель класса энергоэффективности IE2, обеспечивает экономию 118,6 евро за год и 2000 евро за жизненный цикл, по сравнению с асинхронным двигателем класса IE1. Рассчитан срок окупаемости двигателя класса IE2, который составляет 5 месяцев в случае введения в строй новой установки и 2 года, в случае замены двигателя в работающей установке.