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

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)

Comparative Study of Electrically Excited Conventional and Homopolar Synchronous Motors for the Traction Drive of a Mining Dump Truck Operating in a Wide Speed Range in Field-Weakening Region

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. © 2022 by the authors

Оптимизация параметров вторичного элемента односторонних линейных асинхронных электродвигателей с использованием генетического алгоритма

The article focuses on the use of genetic algorithms for the design of linear induction motors. Comparison of genetic algorithm with classical methods in the context of electrical machines designing has been carried out. The results of solving an optimization problem for two designs are presented, viz. a laboratory linear induction electric motor based on a three-phase SL-5-100 inductor and a traction single-sided linear induction electric motor of an urban transport system. The optimality criterion included maximizing the power factor and efficiency, as well as the rigidity of the mechanical characteristic while ensuring a starting traction force of at least a set value. The results of optimization of such parameters of the secondary element as the width and thickness of the conductive strip as well as the thickness of the magnetic circuit are described. The relevance of the problem of optimizing the parameters of the secondary element with unchanged parameters of the inductor is due to the fact that the same inductor can be used to build various structures, while the secondary element is created for each specific application and integrated directly into the working body of the mechanism or is a driven product. To calculate the traction and energy characteristics of linear induction electric motors, an electromagnetic model based on detailed equivalent circuits was used, taking into account longitudinal and transverse edge effects and providing a calculation time for one set of parameters of about 1 s. In accordance with this model, the electric motor is reduced to a set of three detailed equivalent circuits: a magnetic circuit, primary and secondary electrical circuits. The result of the optimization of these electric motors was an increase in the efficiency by 1.6 and 1.4 %, respectively, an increase in the power factor by 0.9 and 0.2 %, and an increase in the rigidity of traction characteristics and starting traction force. © Belarusian National Technical University, 2021

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

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)

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)

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)

Comparative Study of Induction and Wound Rotor Synchronous Motors for the Traction Drive of a Mining Dump Truck Operating in Wide Constant Power Speed Range

Motors with rare earth permanent magnets are the most compact and energy efficient in most applications. However, their use as traction motors for off-highway vehicles, such as mining dump trucks, is challenging not only because of the high cost of the magnets, but also because of the difficulty of providing a wide range of constant power speed control due to the unregulated permanent magnet flux. For this reason, induction motors remain the most popular type of motor for hybrid and all-electric mining dump trucks. However, the use of an induction motor results in increased power loss, increased current, and high temperature ripple of the power switches of the solid-state inverter when stopping on a slope with an electric brake. In this article, a theoretical comparison between an induction motor (IM) and a magnet-free wound rotor synchronous motor (WRSM) with a rotor DC-excitation in a mining dump truck drive is presented. Both motors have an identical stator outer diameter, and their geometry is optimized using the Nelder-Mead method. 2D finite element analysis in the time domain is used to calculate the IM characteristics. Steady-state characteristics of the motors such as efficiency, losses, torque ripple, required inverter power, dimensions, weight and cost of active materials are compared. In addition, losses and temperature ripples in the power modules of the semiconductor inverter, which affect the reliability of the drive, are compared when using the considered motors. The study demonstrates that the WRSM offers significant benefits such as reduced power loss, inverter power requirement, cost and mass of active materials, making it promising for use in mining trucks. © 2013 IEEE.Ministry of Education and Science of the Russian Federation, Minobrnauka: FSWF-2023-0017This work was supported by the Ministry of Science and Higher Education of the Russian Federation under Project FSWF-2023-0017

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