Aleksey Paramonov

In contemporary automotive, maritime, and commercial vehicle technology, various types of transport rely on permanent magnet synchronous motors for their space-saving advantages. However, these motors come with certain drawbacks. Permanent magnets, while efficient, can prove costly and have issues maintaining consistent flux, especially when requiring wide constant power speed ranges in the field weakening domain. Consequently, an appealing substitute for permanent magnet motor systems might involve motors that incorporate a field winding, offering potential benefits in terms of both cost and performance adaptability. The article presents a new design of a traction synchronous motor with a field winding on the rotor with a two-phase brushless harmonic exciter that increases the electromotive force on the field winding. This article also proposes a zero-sequence current injector circuit using only the lower transistor, which does not require an expensive upper driver. Its mathematical model is proposed considering PWM and the simulation results are presented. The operation of the motor with relay control of the excitation flux is considered.

Many modern electric drives for cars, trucks, ships, etc., use permanent magnet synchronous motors because of their compact size. At the same time, permanent magnets are expensive, and their uncontrolled flux is a problem when it is necessary to provide a wide constant power speed range in the field weakening region. An alternative to permanent magnet motors is synchronous motors with field windings. This article presents a novel design of a traction brushless synchronous motor with a field winding and a two-phase harmonic exciter winding on the rotor and zero-sequence signal injection. The two-phase harmonic exciter winding increases the electromotive force on the field winding compared to a single-phase one and makes it possible to start the motor at any rotor position. This article discusses the advantages of the proposed design over conventional solutions. A simplified mathematical model based on the finite element method for steady state simulation is presented. The machine performance of a hysteresis current controller and a field-oriented PI current controller are compared using the model.

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.

Line-start permanent magnet synchronous motors (LSPMSMs) are of great interest to researchers because of their high energy efficiency, due to the growing interest of manufacturers in energy-efficient units. However, LSPMSMs face some difficulties in starting and synchronization processes. The LSPMSM lumped parameter model is applicable to estimating the successfulness of starting and further synchronization. The parameters of such a model can be determined using computer-aided identification algorithms applied to real motor transient processes’ curves. This problem demands significant computational time. A comparison between two algorithms, differential evolution and Nelder–Mead, is presented in this article. The algorithms were used for 0.55 kW, 1500 rpm LSPMSM parameter identification. Moreover, to increase computational speed, it is proposed to stop and restart the algorithms’ procedures, changing their parameters after a certain number of iterations. A significant advantage of the Nelder–Mead algorithm is shown for the solving of the considered problem.

The use of Line-Start Permanent Magnet Synchronous Motors (LSPMSM) improves the efficiency of conventional direct-on-line electric motor-driven fluid machinery such as pumps and fans. Such motors have increased efficiency compared to induction motors and do not have an excitation winding compared to classical synchronous motors with an excitation winding. However, LSPMSMs have difficulty in starting mechanisms with a high moment of inertia. This problem can be exacerbated by a reduced supply network voltage and a voltage drop on the cable. This article investigates the transients during the startup of an industrial centrifugal pump with a line-start permanent magnet synchronous motor. The simulation results showed that when the voltage on the motor terminals is reduced by 10%, the synchronization is delayed. The use of the cable also leads to a reduction in the voltage at the motor terminals in a steady state, but the time synchronization delay is more significant than that with a corresponding reduction in the supply voltage. The considered simulation example shows that the line-start permanent magnet synchronous motor has no problems with starting the pumping unit, even with a reduced supply voltage. The conclusions of this paper support a wider use of energy-efficient electric motors and can be used when selecting an electric motor to drive a centrifugal pump.

Direct-on-line synchronous motors are a good alternative to induction motors in fluid machinery drives due to their greater energy efficiency but have the significant disadvantage of limiting the maximum moment of inertia of the loading mechanism to ensure their successful and reliable start-up. This disadvantage is critical in centrifugal fans with a massive steel impeller. In this article, using a mathematical model, the dynamics of starting and synchronizing a permanent magnet synchronous motor fed directly from the mains as part of a fan drive are studied. The simulation results show the possibility of increasing the maximum moment of inertia of the load at the successful start-up of a direct-on-line synchronous motor by adjusting the hydraulic part of the fan pipeline by means of throttling. The conclusions of this paper can be used when selecting an electric motor to drive industrial fans and can contribute to wider use of energy-efficient synchronous motors with direct start-up from the mains.

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.

Рассмотрено применение генетического алгоритма для проектирования линейных асинхронных электродвигателей, проведено его сравнение с классическими методами. Представлены результаты решения оптимизационной задачи для двух конструкций: лабораторного линейного асинхронного электродвигателя на базе трехфазного индуктора SL-5-100 и тягового одностороннего линейного асинхронного электродвигателя городской транспортной системы. Критерий оптимальности включал максимизацию коэффициентов мощности и полезного действия, а также жесткости механической характеристики при обеспечении пускового тягового усилия не менее заданного значения. Описаны результаты оптимизации таких параметров вторичного элемента, как ширина и толщина проводящей полосы, толщина магнитопровода. Актуальность задачи оптимизации параметров вторичного элемента при неизменных параметрах индуктора обусловлена тем, что один и тот же индуктор может использоваться для построения различных конструкций, при этом вторичный элемент создается под каждое конкретное применение и интегрируется непосредственно в рабочий орган механизма либо является приводимым в движение изделием. Для расчета тяговых и энергетических характеристик линейных асинхронных электродвигателей использовалась электромагнитная модель на основе детализированных схем замещения, учитывающая продольный и поперечный краевые эффекты и обеспечивающая время расчета для одного набора параметров около 1 с. В соответствии с данной моделью электродвигатель сводится к совокупности трех детализированных схем замещения: магнитной цепи, первичной и вторичной электрических цепей. Результатом оптимизации указанных электродвигателей стало повышение коэффициента полезного действия на 1,6 и 1,4 % соответственно, коэффициента мощности – на 0,9 и 0,2 %, увеличение жесткости тяговых характеристик и пускового тягового усилия.

Aim. The comparative analysis of energy consumption, electricity costs during lifetime cycle and payback period of a pump unit with 90 kW 2-pole induction motors, belonging to various energy efficiency classes, feeding directly from power grid. Methods. The examined operating modes aligned with a typical operating cycle of a pump unit with approximately constant flow rate of 75-110 % of the rated flow. The calculations were based on the pump and induction motors nameplate data, which, in their turn, were based on the manufacturers’ experimental data. Results. The calculations of energy consumption, electricity costs and payback periods of a pump unit with 90 kW 2-pole induction motors, feeding directly from power grid have been performed in the article. The application of induction motors belonging to IE2, IE3 and IE4 energy efficiency classes has been discussed. Practical value. It has been demonstrated, than in case of replacement of an induction motor of energy efficiency class IE2 due to planned retrofit, payback period for an IE4 induction motor is 2.18 years, energy savings within a calculated 20-year operating period are 268MW·h, which makes €41110 in money terms. Under the same conditions, the replacement of an induction motor of energy efficiency class IE2 with an induction motor of energy efficiency class IE3 will allow to save 88 MW·h within a calculated operating period, which, expressed in monetary terms, is €13500 and the payback period is 5.11 years. Thus, the article proves that despite a higher initial price, the choice of an induction motor of energy efficiency class IE4 tends to be more economically advantageous.

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