Comparison of minimum energy consumption indicators for electric motors powered directly from the mains at part loads

The article presents a comparison of minimum energy consumption indicators for motors powered directly from the mains at part load conditions. The energy characteristics of induction motors and line-start permanent magnet synchronous motors of different energy efficiency classes are compared. As an example, the calculations of proposed energy consumption indicators are provided for the throttle-controlled 2.2 kW pump unit with variable flow-time profile. It is shown that if a motor is used mostly at part load conditions and was chosen by its energy efficiency class only, minimum energy consumption might not be achieved. Universal average efficiency indicator is suggested for motors running at variable loads with output power much lower than the rated power. The comparison shows that the proposed average efficiency does not depend on a specific application or load profile and describes the motor energy consumption enough for practical goals. Thus, this indicator can be used for fast evaluation and selection of a motor by the lowest energy consumption criterion, especially without detailed information about load profile. Calculation of this indicator requires only motor efficiency data per 4 points 25, 50, 75, 100% of rated load. © Published under licence by IOP Publishing Ltd

Energy efficiency analysis of fixed-speed pump drives with various types of motors

The paper presents a comparative analysis of energy consumption by 2.2 kW electric motors of various types and energy efficiency classes in the electric drive of a pump unit with throttle control in a water supply system. Line-start permanent-magnet synchronous motors of the IE4 energy efficiency class and induction motors of the IE4 and IE3 energy efficiency classes of various manufacturers were considered (IE4 and IE3 are labels of energy efficiency classes of electric motors according to IEC 60034-30-1 standard). Energy consumption at a hydraulic load changing under a typical duty cycle was calculated based on the nameplate data of the pump and electric motors. The developed method shows that selecting an electric motor based on the IE energy efficiency class under the IEC 60034-30-1 standard (i.e., based on efficiency at a rated load) may not provide the minimum energy consumption of a variable flow pump unit over a typical duty cycle. In particular, the considered IE4 class line-start permanent-magnet synchronous motors do not provide significant advantages over IE4 class induction motors, and sometimes even over IE3 class induction motors when they are used in variable flow pump units. © 2019 by the authors.Ministry of Education and Science of the Russian Federation, MinobrnaukaThe research was conducted as part of theme no. 8.9549.2017/8.9. within the frame of the government task of the Ministry of Education and Science of the Russian Federation regarding R&D

Developing the mechatronics and robotics at Nizhny Tagil Technological Institute of Ural Federal University

This report concerns the development trends of the Mechatronics and Mechanics at Nizhny Tagil Technological Institute (branch of Ural Federal University)

Comparative Study of Energy Consumption and co2 Emissions of Variable-Speed Electric Drives with Induction and Synchronous Reluctance Motors in Pump Units

This study carried out a comparative analysis of indicators of electricity consumption and CO2 emissions for four-pole induction motors (IMs) of efficiency classes IE3 and IE4 with a rated power of 2.2–200 kW in a variable speed pump unit. In addition, innovative IE4 converter-fed synchronous reluctance motors (SynRMs) were evaluated. The comparison was derived from the manufacturer’s specifications for the power drive systems (PDSs) at various rotational speeds and loads. The results showed that the emission indicators for IE3 class motors were significantly worse compared with IE4 class motors for low power ratings, which make up the vast majority of electric motors in service. This justifies expanding the mandatory power range for IE4 motors to at least 7.5–200 kW or even 0.75–200 kW, as it will dramatically contribute to the achievement of the new ambitious goals for reducing greenhouse gas emissions. In addition, the operational advantages of IE4 SynRMs over IE4 IMs were demonstrated, such as their simpler design and manufacturing technology at a price comparable to that of IE3 IMs. © 2021 by the authors. Licensee MDPI, Basel, Switzerland.Funding: The work was partially supported by the Ministry of Science and Higher Education of the Russian Federation (through the basic part of the government mandate, Project No. FEUZ 2020-0060)

Comparative study of induction motors of IE2, IE3 and IE4 efficiency classes in pump applications taking into account CO2 emission intensity

The high energy intensity of the modern industry and the threat of climate change determine the high urgency of increasing the energy efficiency of electric motors. In this paper, energy consumption, energy costs, payback periods, and CO2 emissions of 75 kW, 4 pole induction motors with direct grid supply in a fixed-speed pump unit are evaluated. Motors of the IE2, IE3, and IE4 efficiency classes according to IEC 60034-30-1 standard are compared in terms of life-time energy savings, payback period, and CO2 emissions. To carry out the analysis, polynomial interpolation of the data from the available manufacturer datasheets of the motors is used. It concluded that even though the initial investment cost of the IE4-motor is higher than that of IE3-motor, the IE4-motor is more profitable if more than 3 years of operation are considered and also provides significant reductions of CO2 emissions. The paper presents a calculation method of the aforementioned indicators which can be useful for companies, researchers, and engineers for quick assessment and selection of technical solutions. © 2020 by the authors. Licensee MDPI, Basel, Switzerland.The work was partially supported by the Ministry of Science and Higher Education of the Russian Federation (through the basic part of the government mandate, Project No. FEUZ-2020-0060)

Analysis of Coupled Thermal and Electromagnetic Processes in Linear Induction Motors Based on a Three-Dimensional Thermal Model

The article describes a mathematical model of interconnected electromechanical and thermal processes in a linear induction motor (LIM). Here, we present the structure of the thermal model and provide the calculation formulas of the model. The thermal model consisted of eight control volumes on each tooth pitch of the LIM. Moreover, we also present a model of electromechanical processes and its interaction with the thermal model. The electromechanical model was based on the detailed magnetic and electrical equivalent circuits of the LIM. Model verification was performed using a model based on the finite element method and using experimental data. We also conducted a study focused on the necessity of considering the influence of various features of the thermal processes. We herein discuss the application of the model implemented in the MATLAB/Simulink, which was used to analyze the thermal performance of linear transport and technological induction motors. For the traction single-sided linear induction motor, we determined limits of safe operation by considering the unevenness of heating along the length in two cases: natural cooling and forced cooling. For forced cooling, required values of air flow were determined. For the arc induction motor of the screw press, the influence of various factors (i.e., reduction of the stroke, the use of a soft start, and the use of a forced cooling) on heating was evaluated. © 2021 by the authors. Licensee MDPI, Basel, Switzerland.Funding: The work was partially supported by the Ministry of Science and Higher Education of the Russian Federation (through the basic part of the government mandate, Project No. FEUZ 2020-0060)

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

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