ПОРІВНЯЛЬНИЙ АНАЛІЗ МАГНІТНИХ СИСТЕМ ЕЛЕКТРОДВИГУНІВ З ПОСТІЙНИМИ МАГНІТАМИ ДЛЯ ТРАМВАЯ
A numerical study of eight configurations of magnetic systems of electric motors with permanent magnets for driving a tram was carried out. The permanent magnet electric motor can be used as a high-speed electric drive to replace the existing DC electric drive of a tram, and as a low-speed gearless...
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| Дата: | 2021 |
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| Автори: | , , |
| Формат: | Стаття |
| Мова: | Англійська |
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Інститут електродинаміки НАН України, Київ
2021
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Technical Electrodynamics| _version_ | 1870287621637275648 |
|---|---|
| author | Гребєніков, В.В. Гамалія, Р.В. Дадичін, С.А. |
| author_facet | Гребєніков, В.В. Гамалія, Р.В. Дадичін, С.А. |
| author_institution_txt_mv | [
{
"author": "В.В. Гребєніков",
"institution": "Інститут електродинаміки НАН України, пр. Перемоги, 56, Київ, 03057, Україна"
},
{
"author": "Р.В. Гамалія",
"institution": "Інститут електродинаміки НАН України, пр. Перемоги, 56, Київ, 03057, Україна"
},
{
"author": "С.А. Дадичін",
"institution": "Інститут електродинаміки НАН України, пр. Перемоги, 56, Київ, 03057, Україна"
}
] |
| author_sort | Гребєніков, В.В. |
| baseUrl_str | https://techned.org.ua/index.php/techned/oai |
| collection | OJS |
| datestamp_date | 2021-08-26T09:44:28Z |
| description | A numerical study of eight configurations of magnetic systems of electric motors with permanent magnets for driving a tram was carried out. The permanent magnet electric motor can be used as a high-speed electric drive to replace the existing DC electric drive of a tram, and as a low-speed gearless electric drive of a new generation tram. The most promising configurations of magnetic systems of electric motors with permanent magnets for tram drive have been determined. By varying the geometrical and winding parameters of each of the investigated models of electric motors, the mechanical characteristics are determined, at which the given torque and power are achieved in the entire range of the rotor speed. Also, a thermal calculation was performed taking into account the urban driving cycle of high-speed electric motors with air cooling by a fan and low-speed ones in liquid cooling mode. The calculation of the characteristics of the investigated electric motors was carried out in the Simcentre MotorSolve software package. References 13, figures 8, tables 3. |
| doi_str_mv | 10.15407/techned2021.05.027 |
| first_indexed | 2026-06-16T01:04:05Z |
| format | Article |
| fulltext |
ISSN 1607-7970. Техн. електродинаміка. 2021. № 5 27
ЕЛЕКТРОМЕХАНІЧНЕ ПЕРЕТВОРЕННЯ ЕНЕРГІЇ
DOI: https://doi.org/10.15407/techned2021.05.027
COMPARATIVE ANALYSIS OF MAGNETIC SYSTEMS
OF PERMANENT MAGNET MOTORS FOR TRAM
V.V. Grebenikov*, R.V. Gamaliia**, S.A. Dadychyn
Institute of Electrodynamics of National Academy of Sciences of Ukraine
Pr. Peremohy, 56, Kyiv, 03057, Ukraine, e-mail: elm1153@gmail.com
A numerical study of eight configurations of magnetic systems of electric motors with permanent magnets for driving a
tram was carried out. The permanent magnet electric motor can be used as a high-speed electric drive to replace the
existing DC electric drive of a tram, and as a low-speed gearless electric drive of a new generation tram. The most
promising configurations of magnetic systems of electric motors with permanent magnets for tram drive have been
determined. By varying the geometrical and winding parameters of each of the investigated models of electric motors,
the mechanical characteristics are determined, at which the given torque and power are achieved in the entire range of
the rotor speed. Also, a thermal calculation was performed taking into account the urban driving cycle of high-speed
electric motors with air cooling by a fan and low-speed ones in liquid cooling mode. The calculation of the
characteristics of the investigated electric motors was carried out in the Simcentre MotorSolve software package.
References 13, figures 8, tables 3.
Keywords: numerical modeling, electric motor, permanent magnets, electromagnetic torque, performance
characteristics, thermal calculation, electric tram drive.
Introduction. The current level of development of electric motors with permanent magnets and
power converters (inverters) allows us to consider them for new promising tram electric drive systems.
Currently, most tram cars use DC traction motors with series excitation [1]. This drive generates increased
torque at low speed and limited torque at high speed, which ensures the necessary dynamics of the tram. In
most cases, one voltage converter drives two motors joined in series. However, a series-excited DC traction
motor has several disadvantages. The drive does not fully provide dynamic braking at low tram speed. The
presence of a brush assembly reduces the resource and reliability of the engine. Probably, the modernization
of the traction drive based on DC motors with series excitation has reached its limit. Further improvement of
the tram drive efficiency is possible only with the transition to a new type of drive: asynchronous [2, 3],
permanent magnet motors [4, 5], etc.
Favorable conditions for the creation of new traction electric drive systems are provided by the
availability of modern efficient frequency converters of alternating current (inverters) on the market.
Therefore, at present, the AC traction drive system has become widespread. The traction drive includes a
frequency converter (inverter) and an AC motor: asynchronous or permanent magnet motor. The frequency
converter (inverter) provides the operation of one or two motors connected in parallel. As an example, we
can cite converters (inverters) of the BORDLINE CC400 DC type manufactured by ABB [6]. The AC
traction drive increases the efficiency and reliability of the drive.
Permanent magnet motors are one of the most promising for use in traction electric drives. When
using liquid cooling, permanent magnet motors provide the highest specific performance (torque and power
developed per unit mass of the motor). The small overall dimensions of the permanent magnet electric motor
make it possible to use more advanced kinematic diagrams of the tram car driving bogies.
Eventually, a drive system based on a frequency converter (inverter) and a permanent magnet motor
can compete with a traditional DC drive system. There are a large number of magnetic system configurations
for a permanent magnet traction drive. The advantage of a particular configuration can be determined based
on the requirements for the drive, as a rule, these are the overall dimensions of the electric motor and the
type of mechanical characteristics depending on the rotor speed [7–9].
© Grebenikov V.V., Gamaliia R.V., Dadychyn S.A., 2021
ORCID ID: * https://orcid.org/0000-0002-1114-1218 ; ** https://orcid.org/0000-0002-5729-7891
28 ISSN 1607-7970. Техн. електродинаміка. 2021. № 5
Research purpose. The aim of this work is a comparative analysis of several configurations of the
magnetic system of electric motors with permanent magnets in relation to the traction drive of a city tram
and an analysis of the advantages and disadvantages of various configurations of the magnetic systems of
electric motors. In the course of the study, electric motors with permanent magnets are conventionally
divided into two groups: high-speed motors (rated speed n=1750 rpm) as a variant of replacing the existing
traction electric drive of the tram; low-speed motors (n=320 rpm) for a gearless traction electric drive of
perspective low-floor tram models.
The first group of high-speed motors is designed to replace the existing TE-022 DC traction motor of
the T-3 tram. In this group, numerical investigations of four configurations of the magnetic system of electric
motors with a power of P=45 kW, n=1750 rpm were carried out. The second group of low-speed engines is
intended for the gearless drive of promising tram models. In this group, four modifications of the magnetic
system were also investigated, which have a power of P=46 kW and rated speed n=320 rpm. The same
power of the engines under study is the main criterion for comparing engines of different designs. Permanent
magnet motors of each group differ from each other in the configuration of the rotor and stator.
For each of the design options for an electric motor with permanent magnets, a calculation cycle is
envisaged in order to find the best option by varying a number of parameters (configuration of the magnetic
system of the rotor and stator, winding data, material properties).
Permanent magnet motor as an alternative to the existing TE-022 motor. The existing TE-022
engine of the T-3 tram is a DC motor with series excitation [1]. The main parameters of the TE-022 engine
are as follows: rated power – 45 kW; rated speed – 1750 rpm; maximum rotation speed – 4200 rpm; rated
voltage – 300 V; rated current – 150 A; efficiency – 91%; cooling air consumption – 7.5 m3 / min; electric
motor weight – 320 kg; length – 683 mm, diameter – 400 mm.
The mechanical characteristics of the TE-022 electric motor are favorable (convenient) for driving a
tram. The maximum (starting) torque of the traction electric drive is M=650 Nm. The maximum torque is
limited by the maximum current supplied by the drive control system. Most of the TE-022 traction motor
control systems provide a maximum motor current of no more than 300 A. With an increase in the rotational
speed, the torque and current of the electric motor decreases and at a rated speed of n=1750 rpm the
electromagnetic torque is M=260 Nm. At the maximum rotational speed n=4200 rpm, the torque is
M=50 Nm. The mechanical characteristic of the permanent magnet motor should be similar to that of the
existing TE - 022 motor.
The investigated system of a traction electric drive based on an electric motor with permanent
magnets provides for the installation of a converter (inverter) to control one or two motors connected in
parallel. The maximum torque of a permanent magnet motor is provided by the maximum output current of
the converter (inverter). The permanent magnet motor is cooled by an air cooling system.
All investigated variants of electric motors with permanent magnets have the same outer diameter of
the stator magnetic system, and the same electromagnetic loads (current density, magnetic induction value in
the stator teeth) are set for all variants. The current density in the windings at the rated speed is assumed to
be J=4.0 A/mm2, during start-up – J=10 A/mm2. The magnitude of the magnetic induction in the stator teeth
is limited to B=2.0 T.
A general view of the design options for the first group of the studied electric motors with permanent
magnets with a nominal speed of n=1750 rpm is shown in Fig. 1. The lower part of this figure shows a
general view of the rotor of each of the electric motors. To reduce the cogging torque the rotor poles skew is
made by one toothed division [10]. The M1 electric motor is multi-pole. The phase windings of the electric
motor are coils that are winded up on the stator teeth (covering the stator teeth), the dimension of stator iron
back is smaller than that of the stator of a traditional synchronous motor. There is an optimum ratio between
the number of rotor poles and the number of stator teeth that provides the best performance for the motor.
High electromagnetic loads are provided in the electric motor: magnetic induction in the air gap and linear
current load of the windings. The magnetic flux of the rotor pole is created by magnets with tangential
magnetization. By choosing a larger pole height (size of the magnets), it is possible to provide an increased
magnetic flux density in the motor gap. The lumped stator winding allows you to increase the size of slots
and, accordingly, increase the linear current load of the electric motor. At present, electric motors of this type
are produced in series mainly for low-speed gearless electric drives.
The M2 motor uses the traditional design of a permanent magnet synchronous motor, in which the
rotor poles are composed of tangentially magnetized prismatic permanent magnets, the stator contains a
distributed winding in which the phase coil covers the pole division. The M3 electric motor, in contrast to the
ISSN 1607-7970. Техн. електродинаміка. 2021. № 5 29
M2 electric motor, has a rotor with magnets of radial magnetization. To reduce eddy current losses,
permanent magnets of rotor poles are divided into 6 parts.
The M4 electric motor has an implicit-pole rotor, which is a package of electrical steel with
permanent magnets. The rotor electrical steel package has slots in which permanent magnets are installed.
Structurally, all elements of the rotor magnetic circuit are located on the sheet of electrical steel: the north
and south poles, the "back" of the rotor poles. The elements of the rotor magnetic circuit are interconnected
by thin bridges, which provide a simple technology for manufacturing the rotor. The dimensions of the
bridges provide the mechanical strength of the rotor with a slight negative effect on the magnitude of the
rotor magnetic flux. There are various options for the configurations of the rotor poles. The skew of the rotor
poles is performed by a set of rotor sections shifted relative to each other by a given angle. At present, this
design of an electric motor with permanent magnets is one of the most promising for use in electric transport.
M1 M2 M3 M4
Fig. 1
For each of the design variants of the permanent magnet electric motor, a calculation cycle was
performed. By varying the basic geometrical parameters of the rotor and stator magnetic systems, winding
data and the properties of permanent magnets, a search was made for the best option, taking into account the
requirements for the drive (the power developed by the motor at a given rotor speed). Comparison of various
engine options was carried out at the same electromagnetic loads.
The calculation of the characteristics of electric motors is carried out in the Simcenter MotorSolve
package [13], which allows you to set the mode of electric current control of the motor. A sinusoidal form of
the supply current is adopted for all motor variants. Magnetic field patterns for the nominal mode of each of
the options are shown in Fig. 2. Analyzing the calculation results it should be noted that the maximum
magnetic induction in the teeth of the investigated electric motors is as follows: M1 – BM1 (tooth) = 1.92 T;
M2 – BM2 (tooth)=1.87 T; M3 – BM3 (tooth)=1.86 T; М4 – BM4 (tooth)=1.79 T. In the back of the stator, the
maximum values of the magnetic induction are as follows: M1 – BM1 (back) = 1.48 T; M2 – BM2 (back) = 1.82 T;
M3 – BM3 (back) =1.93 T; М4 – BM4 (back)=1.79 T. Thus, the dimensions and geometry of the magnetic system
are selected in such a way that the condition is fulfilled: the induction in the teeth and back of the stator is
limited to B=2.0 T.
Fig. 2
30 ISSN 1607-7970. Техн. електродинаміка. 2021. № 5
It should be noted that the considered permanent magnet motors must provide power in a wide range
of speed variation: from operating to maximum. The maximum rotational speed n=4200 rpm is more than
twice the operating speed n=1750 rpm. It is known that for permanent magnet electric motors providing a
wide variation in rotational speed is a problem. In a traditional permanent magnet motor, the flux is constant
and unregulated. With an increase in the rotor speed, the back-EMF induced in the stator windings also
increases, which leads to a decrease in the current in the windings. Thus, the maximum speed and power of
the motor are limited and depend on the parameters of the stator winding and the properties of the permanent
magnets of the rotor.
The fulfillment of the condition (requirement) for regulating the speed of the electric drive in a wide
range is ensured by the converter (inverter) by controlling the moments of switching the windings. The
moment of switching the motor windings is determined by the advance angle between the position of the q-
axis of the rotor and the middle axis of the switched winding. The value of the lead angle affects the value of
the rotor magnetic flux and, accordingly, the windings back-EMF. When carrying out numerical studies, the
lead angle was varied in such a way as to provide the maximum torque for a given rotor speed.
By varying the geometrical and winding parameters of each of the investigated models of electric
motors, the mechanical characteristics were determined at which a given torque and power is achieved in the
entire range of the rotor speed. As a result of numerical studies, promising designs of electric motors with
permanent magnets were found, on the basis of which it is advisable to create a tram electric drive. The
calculated characteristics of various options for electric motors are shown in Fig. 3. In Fig. 3, a shows the
dependences of the moment on the shaft of the electric motor, and in Fig. 3, b – dependence of power on the
rotor speed. The characteristics are given at the rated current in the motor windings.
а b
Fig. 3
Table 1 shows the technical parameters of the investigated electric motors with permanent magnets,
which can be considered as an option for replacing the existing TE-022 motor.
The main structural dimensions of the magnetic system of each version of the electric motor were
obtained by performing a series of calculations taking into account the fulfillment of the basic requirements:
ensuring the rated torque at rated speed and the highest possible torque at maximum speed. The calculating
results of the characteristics of electric motors with permanent magnets show that the variants of electric motors
M1, M3, M4 provide a given torque (P≥260 Nm) at a nominal speed n=1750 rpm and for an electric motor M2
it is slightly less and is P=251 Nm. In this case, in all versions of the investigated electric motors, the current
density in the windings and the magnetic induction in the stator steel are the same. All variants are brought to
the same power level (46÷51 kW) by changing the motor length. With the same motor diameter and its
electromagnetic loads, the motor length can be a criterion for comparing different motor options.
Numerical studies have shown that the M1 multi-pole electric motor has the greatest length of the
magnetic system in comparison with other options. However, the length of the magnetic system of the M1
electric motor is significantly less than the corresponding length of the TE-022 DC motor. The result of the
calculation of the M1 electric motor confirms the possibility of using a multi-pole electric motor with
permanent magnets and lumped windings for a relatively high-speed drive (n=1750 rpm). The mechanical
performance of the M1 electric motor is acceptable for transport systems. The starting torque of this motor is
higher than that of other electric motor options.
The calculation results for electric motors M2 and M4 confirm the prospects of these motors for
ISSN 1607-7970. Техн. електродинаміка. 2021. № 5 31
replacing the existing TE-022 drive. The design of the motors provides for salient-poles steel rotor, which
are adjoined by permanent magnets. By choosing the configuration of the pole and magnets, a large amount
of magnetic flux through the pole can be achieved with a relatively low reluctance of the main magnetic
circuit. The relatively low resistance of the main magnetic circuit favorably affects the ability of the control
system to regulate the motor torque by changing the lead angle of the winding commutation.
Table 1
М1 М2 М3 М4
Poles number 10 6 4 6
Stator slots number 12 18 12 18
Number of turns 14 7 14 6
Stator outer diameter mm 350 350 350 350
Stator / rotor length mm 240 200 200 200
Rotor diameter mm 210 210 220 206
Air gap mm 1,0 1,0 1,0 1,0
Skew of poles on the rotor deg 30 20 30 20
Stator steel weight kg 70,6 68,7 54,6 73,7
Rotor steel weight kg 22,2 27,9 27,2 33,5
Windings (copper) weight kg 25,8 19,0 33,4 16,6
Weight of magnets kg 6,75 3,15 2,94 4,05
Total mass of the magnetic system kg 125 119 118 128
Magnetic system volume m3 0.023 0.019 0.019 0.019
Rated voltage V 600 600 600 600
Rated current A 75 75 75 75
Current density A/mm2 3,83 4,04 3,95 3,92
Rated mode
Lead angle el.degrees 40 35 15 30
Rated speed rpm 1750 1750 1750 1750
Rated torque Nm 279 251 262 264
Rated power kW 51 46 48 48,4
Specific power kW/m3 2210 2387 2496 2517
Specific torque kW/m3 12089 13051 13623 13727
Maximum mode
Lead angle el.degrees 72 69 64 71
Maximum speed rpm 4200 4200 4200 4200
Torque Nm 134,1 127 127 84,2
Power kw 55,8 55,7 55,8 39,8
Start mode
Lead angle el.degrees 0 10 10 30
Rotor speed rpm 500 500 500 500
Starting current A 200 200 200 200
Starting torque Nm 964 674 700 746
The calculation results for the M3 electric motor with permanent magnets installed on the outer
surface of the rotor show a significant effect of the number of winding turns on the mechanical
characteristics of the motor. Even with a decrease in the number of poles to four, with an increase in the
frequency of rotation above the nominal, back-EMF winding increases significantly and causes a decrease in
current and torque. Installing magnets on the outer surface of the rotor with radial magnetization increases
the reluctance of the magnetic circuit. With this configuration of the magnetic system, the ability of the
control system to reduce the magnetic flux is limited. With the accepted limitation of the current density in
the windings, the magnetomotive force (MDF) of the stator winding does not provide sufficient attenuation
of the magnetic flux of the rotor with permanent magnets. As a result, the mechanical characteristic of the
M3 electric motor at a speed higher than the rated speed does not provide the required stiffness of the
characteristic. The best specific characteristics at the rated rotor speed of the M4 electric motor, however,
this motor has the lowest power and torque at the maximum rotor speed (n=4200 rpm).
32 ISSN 1607-7970. Техн. електродинаміка. 2021. № 5
The mechanical characteristics of a permanent magnet electric motor largely depend on the control
system of the electric motor – the frequency converter. The maximum motor torque is determined by the
maximum current that the frequency converter can supply. Calculations of all variants of electric motors with
permanent magnets showed that there are no restrictions on reaching three times the rated torque. When the
motor is supplied with a current of 200 A, the voltage on the motor at start is less than the rated voltage.
Accordingly, there is the possibility of further increasing the current and torque. The starting torque is
limited by the cooling conditions of the winding at start.
Calculations of the variants of electric motors show that within the limits of the overall dimensions
of the TE-022 DC motor, the length of the electric motors with permanent magnets can be increased.
Accordingly, when the length of the permanent magnet motor is increased, a high overload capacity of the
motor can be ensured as compared to the TE-022 DC motor.
Thus, the replacement of the existing TE-022 DC motor with a permanent magnet motor is a
promising project to improve the efficiency and reliability of the T-3 tram.
Low speed gearless traction drive. Nowadays, the requirements for the tram have increased
significantly. A modern tram must be low-floor and provide a comfortable ride for a large number of
passengers. Leading tramway manufacturers are introducing a new motor bogie layout. The new layout of
the bogie provides for independently rotating wheels with a traction drive, which is placed on the outer side
of the wheel [11]. The use of new bogies can significantly improve the efficiency of the tram. An example of
a new tram design is the Skoda FORCITY ALFA tram [12].
The cart of this tram has an individual drive for each wheel, which ensures an ideal ride both on
bends and on straight sections. Traction motors are permanent magnet motors that are directly connected to
the wheel without a gearbox.
The new layout of the tram bogies limits the overall dimensions of the electric motor. Permanent
magnet motors are liquid cooled to generate high torque. Basic parameters of the ŠKODA ELECTRIC HLU
3436 P/44-VA tram drive of the FORCITY ALFA tram (Czech Republic): rated moment – 1460 Nm;
maximum moment – 2270 Nm; rated speed – 320 rpm; maximum rotation speed – 706 rpm; rated current –
85.4 A; electric motor weight – 252 kg.
When studying various design options for permanent magnet electric motors, all of them must meet the
specified technical requirements: torque, power, type of mechanical characteristics. The traction drive must
provide a rated torque Mnom=1450 Nm in continuous operation (S1). In this case, in the range from zero to the
rated speed nnom=200 rpm, the torque of the electric motor must be at least the rated one. With a further increase
in the speed to the maximum value nmax=700 rpm, the power of the electric motor must be at least Pnom=46 kW.
Also, the electric motor must provide a maximum torque Mmax=2270 Nm in short-term duty (S5).
For these initial data, four variants of the configuration of the magnetic system were also
investigated. All variants of permanent magnet motors have the same outer diameter of the magnet system.
Also, for all variants, the same electromagnetic loads (current density, magnetic induction value in the stator
teeth) are set. A general view of the design variants of the investigated electric motors with permanent
magnets is shown in Fig. 4.
The relatively low rotor speed, not more than nmax=700 rpm, allows the use of a larger number of
poles than for M1-M4 electric motors. For the M7 electric motor, the magnets are not divided into parts,
since at a low rotor speed; the effect of eddy currents is not significant.
Magnetic field patterns for the nominal mode of each of the options are shown in Fig. 5. Analyzing
the calculation results, it should be noted that the maximum magnetic induction in the teeth of the
investigated electric motors is as follows: M5–- BM5 (tooth)=1.94 T; M6 – BM6 (tooth)=2.0 T; M7 – BM7
(tooth)=1.82 T; М8 – BM8 (tooth)=1.96 T. In the back of the stator, the maximum values of magnetic
induction are as follows: M5 – BM5 (back)=1.14 T; M6 – BM6 (back)=2.0 T; M7 – BM7 (back)=1.73 T;
М8 – BM8 (back)=1.98 T. For low-speed motors, the condition is also fulfilled that the induction in the teeth
and back of the stator is limited to B=2.0 T.
Calculations of variants for low-speed gearless traction motors with permanent magnets showed that
the main parameter that determines the motor torque is the current density in the windings. The design of the
permanent magnet motor allows high current densities in the windings. The presence of permanent magnets
and the associated high resistance of the magnetic circuit practically exclude saturation of the stator steel at
high currents. As a result, the torque is limited by the permissible current load of the motor windings. With
liquid cooling of an electric motor with permanent magnets, the current density in the windings can reach
ISSN 1607-7970. Техн. електродинаміка. 2021. № 5 33
values up to 20 A/mm2, which ensures high specific indicators of the motor (the ratio of the torque to the
mass of the motor).
М5 М6 М7 М8
Fig. 4
Fig. 5
When performing calculations of various variants for electric motors with permanent magnets, the
current density in the windings was taken equal to 10 A/mm2. At a given current density, the specified torque
of the electric motor was ensured with its limited dimensions (outer diameter, length). The length of the
electric motors in the various variants is from 280 to 335 mm.
By varying the geometrical and winding parameters for each of the investigated models of electric
motors, the mechanical characteristics are determined at which a given torque is achieved at a nominal speed
n=320 rpm and the maximum possible torque is provided with an increase in the rotational speed to n=700 rpm.
The calculated characteristics of various options for electric motors are shown in Fig. 6. In Fig. 6, a shows the
dependences of the moment on the shaft of the electric motor, and in Fig. 6, b – dependence of power on the
rotor speed. The characteristics of the electric motors are given at the rated current of the electric motor.
Table 2 shows the technical parameters of the investigated electric motors with permanent magnets.
When analyzing various design options for permanent magnet electric motors, options M5, M6 and M8
should be highlighted, these options provide rated power in a wide range of rotor speed variation: from
nominal to maximum. The multi-pole design of the rotor allows the control system to fully regulate the
magnetic flux of the motor at maximum speed.
The variant of the M5 electric motor has the best specific performance at the rated speed. The
presence of a large number of rotor poles N=20, when using modern control methods, does not negatively
affect the characteristics of the motor.
34 ISSN 1607-7970. Техн. електродинаміка. 2021. № 5
а b
Fig. 6
The M7 variant does not provide the specified power at the maximum speed. In this case, the control
system does not provide a decrease in the back-EMF stator windings at increased rotor speed. The variant of
the M7 electric motor is inferior in terms of weight and dimensions at the rated rotor speed in comparison
with other options. For the M7 electric motor, the specific characteristics (power and torque referred to the
volume of the electric motor) at the rated speed are the worst.
Table 2
М5 М6 М7 М8
Poles number 20 8 8 8
Stator slots number 24 24 24 24
Number of turns 14 16 9 12
Stator outer diameter mm 400 400 400 400
Stator / rotor length mm 280 300 325 335
Rotor diameter mm 280 230 300 260
Center hole diameter mm 210 120 220 185
Air gap mm 1,0 1,0 1,0 1,0
Stator steel weight Kg 93,6 141 103 143
Rotor steel weight Kg 27,7 53,8 65,2 67,2
Windings (copper) weight Kg 23,1 33 19,7 25,1
Weight of magnets Kg 11,8 8,25 10,0 8,68
Total system weight Kg 156 236 197 244
Magnetic system volume m3 0.0352 0.0377 0.0408 0.0421
Rated current A 85 85 85 85
Current density A/mm2 9,89 9,97 10,10 10,5
Rated mode
Lead angle el.degrees 11 18 5 43
Rated speed rpm 320 320 320 320
Rated torque Nm 1480 1470 1290 1480
Rated power kW 50 49 45 46
Specific power kW/m3 1420 1300 1078 1093
Specific torque Nm/m3 42045 38992 31618 35154
Maximum mode
Lead angle el.degrees 58 75 67 77
Maximum speed rpm 700 700 700 700
Torque Nm 820 670 359 694
Power kw 50 49 26 51
Start mode
Lead angle el.degrees 0 10 10 30
Starting current A 212 212 212 212
Starting torque Nm 3747 4686 3192 3236
ISSN 1607-7970. Техн. електродинаміка. 2021. № 5 35
Fig. 7
Heating calculation of the investigated electric motors. As a result of a number of calculations, by
varying the geometric parameters of the magnetic system of electric motors, the optimal ratios between the
outer and inner diameters of the rotor, as well as the main dimensions of the magnetic system, providing the
required value of the electromagnetic moment in a given range of rotation frequency (n=0 ÷ 4200 rpm for high-
speed and n=0 ÷ 750 rpm – low-speed tram drive). It should be noted that for a high-speed drive, air cooling is
used by a fan; for a low-speed gearless drive, a high value of the electromagnetic torque for a given materials
(permanent magnets, windings, stator and rotor iron) did not exceed the permissible values. Therefore, it is
necessary to perform a thermal calculation of electric motors taking into account the urban driving cycle, which
describes the movement of a vehicle in the city (engine operation at minimum speed, starting and accelerating
to a certain speed, engine braking from one speed to another, parking) [3]. When performing thermal
calculations, the study was carried out for the cycles of tram movement, which are given in Table 3.
Table 3
М1-М4 М5-М8
Interval
Duration
(sec)
Torque
(Nm)
Start Speed
(rpm)
End Speed
(rpm)
Torque
(Nm)
Start Speed
(rpm)
End Speed
(rpm)
1 (overclocking) 14 650 0 500 2300 0 200
2 (motion) 80 260 500 4200 1500 200 700
3 (free moving) 26 0 4200 1750 0 700 320
4 (braking) 10 -200 1750 0 -2000 320 0
5 (parking) 15 0 0 0 0 0 0
The calculation of the temperature of electric motors M1-M4 was carried out in the Infolytica
MotorSolve package [13], taking into account the driving cycle and air cooling by fan. The flow rate of the
cooled air was set equal to 3 m/s. In Fig. 7 shows
the picture of the thermal field for electric motors
M1 ÷ M4. According to the results of the thermal
calculation, all parts of the electric motors do not
heat up above 60° C. The calculation of the
temperature of the investigated electric motors
M5–M8 was carried out in the Infolytica
MotorSolve package [13], taking into account
liquid cooling. The cooling system is a series of
channels evenly spaced along the entire outer
surface of the electric motor housing and oriented
along the axis of rotation of the electric motor. A
coolant (water) is pumped through these channels
with the help of a circulation pump at a
predetermined speed and a predetermined initial
temperature. Moving through the channels of the cooling system, the coolant takes away the heat generated
by the windings of the electric motor.
Initial data for thermal calculation are as follows: number of cooling channels – Nc=120; the shape
of the cooling channels is round; diameter of the cooling channels dc=8 mm; the initial temperature at the
inlet to the cooling channels is 40°С, the capacity of the circulation pump is Q=3 l / min. Fig. 8, a shows a
picture of the thermal field of M6 ÷ M8 electric motors with liquid cooling, from which it follows that all
parts of the electric motors do not heat up above the permissible temperature (the maximum heating
temperature of the M6 motor windings is 120С, for magnets – 110 С (the temperature stability of the
N45SH magnets is 150С). It should be noted that without liquid cooling, the windings and magnets heat up
above the permissible temperature. This is demonstrated by the graphs shown in Fig. 8, b. From these graphs
it follows that in the absence of liquid cooling, the heating temperature of the magnets after 240 minutes of
engine operation is 170С, and the windings – 200С, which is not permissible and would lead to the exit of
the motor from the side.
Conclusions.
1. Numerical research and comparative analysis of various variants of magnetic systems of electric
motors with permanent magnets shows the fundamental possibility of creating on their basis, both traditional
(high-speed) and gearless (low-speed) traction electric tram drive.
36 ISSN 1607-7970. Техн. електродинаміка. 2021. № 5
2. A comparative analysis of various options for permanent magnet electric motors was carried out on
condition that the motors were connected to a sinusoidal current source and optimal regulation was ensured
by changing the moment of switching the windings (lead angle). This power supply mode for electric motors
can be provided by modern power converters with vector control.
a b
Fig. 8
3. Research have shown that all variants of high-speed electric motors with permanent magnets M1,
M2, M3, M4 are competitive with the existing TE-022 DC electric motor and can be promising as its
replacement as one of the options for increasing the efficiency and reliability of the T3 tram. The M4 electric
motor has the best specific characteristics at the nominal rotor speed; however, this motor has the lowest
power and torque at the maximum rotor speed (n=4200 rpm), therefore the most promising options are M2
and M3, since the mass of permanent magnets in these options is the smallest.
4. For a low-speed gearless tram drive of a new generation, variants of electric motors with permanent
magnets M5, M6, M8 are the most promising. The M7 motor version has the best specific performance at the
rated speed. This variant has the largest number of stator poles compared to other variants.
5. Thermal calculation of the investigated electric motors, carried out taking into account the driving
cycle, showed that for a high-speed electric drive, all parts of the electric motors do not heat up above 60°C
when air cooled with a fan. For a low-speed gearless drive with liquid cooling, all parts of the electric motors
do not heat up above the permissible temperature (the maximum heating temperature of the windings is
120C, for the magnets – 110C (the temperature stability of the N45SH magnets is 150C).
Роботу виконано за держбюджетною темою «Розвиток наукових основ і розробка принципів побудови
електромеханічних перетворювачів енергії з постійними магнітами та магнітними редукторами», (шифр
«МАГРЕД»), КПКВК 6541030.
1. Ivanov M.D., Ponomarev A.A., Ieropol'skij B.K. Tram cars T-3. Moskva: Transport, 1977. 240 p. (Rus)
2. Volkov V.A. Optimization of electric consumption of trolleybus with traction frequency-regulated
asynchronous engine and super-condensating driver of generated energy. Elektromekhanіchnі і energozberіgayuchі
sistemi. 2019. Vypusk 1(45). Pp. 87-103. (Rus)
3. Peresada S.M., Kovbasa S.N., Bovkunovich V.S. Comparative testing of algorithms for vector and frequency
control of the torque of an induction motor in electromechanical systems of passenger electric transport. Vіsnik
Kremenchuc'kogo derzhavnogo polіtekhnіchnogo unіversitetu іmenі Mihajla Ostrograds'kogo. 2009. Vypusk 4 (57), ch.
1. Pp. 13-16. DOI: https://doi.org/ela.kpi.ua/handle/123456789/38973. (Rus)
4. Zakharov A., Kobelev A., Makarov L., Skitovich S. Research, Development, Manufacturing and Application
of Energy Efficient Electric Motors. X International Conference on Electrical Power Drive Systems (ICEPDS). 2018.
Novocherkassk, Russia, October 3-6, 2018. Pp. 1-6. DOI: https://doi.org/10.1109/ICEPDS.2018.8571692 .
5. Tergemes K.T., Amangaliyev Y.Z., Karassayeva A.R. Perspective Directions of the Development of Electric
Transports’ Electric Drive. International Multi-Conference on Industrial Engineering and Modern Technologies
(FarEastCon). 2019. Vladivostok, Russia, October 1-4, 2019. Pp. 1-5.
DOI: https://doi.org/10.1109/FarEastCon.2019.8934792 .
ISSN 1607-7970. Техн. електродинаміка. 2021. № 5 37
6. Traction converters. URL: www.abb.com/tractionconverters (accessed: 16.05.2021)
7. Vaskovskyi Yu.M., Haidenko Yu.A., Rusiatynskyi A.E. Mathematical modeling and selecting of construction
parameters for traction synchronous motors with permanent magnets. Tekhnіchna elektrodinamіka. 2013. No 6. Pp. 40-
45. (Rus)
8. Huynh T.A, Hsieh M-F. Performance Analysis of Permanent Magnet Motors for Electric Vehicles (EV)
Traction Considering Driving Cycles. Energies. 2018. Vol. 11(6): 1385. DOI: https://doi.org/10.3390/en11061385 9 .
9. Ehab Sayed, Rong Yang, Jianbin Liang, Mohamed H. Bakr, Berker Bilgin, Ali Emadi. Design of unscrewed
interior permanent magnet traction motor with asymmetric flux barriers and shifted magnets for electric vehicles.
Electric Power Components and Systems. 2020. Vol. 48. No 6-7. Pp. 652-657. DOI:
https://doi.org/10.1080/15325008.2020.1797938
10. Grebenikov V.V., Priymak M.V. Methods for reducing the pulsations of the electromagnetic moment in
electric machines with permanent magnets of tangential magnetization. Vіsnik Natsіonalnoho tekhnіchnoho unіversitetu
KhPІ. 2014. Vypusk 38. Serіya: Elektrichnі mashini ta elektromekhanіchne peretvorennya energії. Pp. 69 – 78. (Rus)
11. Nikitin V.V., Parmas A.YA.-YU., Pivovarov V.M., Sattarov R.R. Gearless traction electric drive of urban rail
transport. Izvestiya PGUPS. Sovremennye tekhnologii – transportu. 2013. No 1. Pp. 31-38. (Rus)
12. Tram «Forcity Alfa» Praga. URL: www.skoda.cz/ru/references/tramcar-forcity-alfa-prague (accessed:
16.05.2021) (Rus)
13. Simcentre Motorsolve URL: https://www.infologicdesign.co.uk/motorsolve (accessed: 16.05.2021)
ПОРІВНЯЛЬНИЙ АНАЛІЗ МАГНІТНИХ СИСТЕМ ЕЛЕКТРОДВИГУНІВ
З ПОСТІЙНИМИ МАГНІТАМИ ДЛЯ ТРАМВАЯ
В.В. Гребеніков*, докт. техн. наук, Р.В. Гамалія**, канд. фіз.-мат. наук, С.А. Дадичін
Інститут електродинаміки НАН України,
пр. Перемоги, 56, Київ, 03057, Україна,
e-mail: elm1153@gmail.com
Проведено чисельне дослідження восьми конфігурацій магнітної систем електродвигунів з постійними
магнітами для приводу трамвая. Електродвигун з постійними магнітами може бути використаний як
високошвидкісний для заміни існуючого електроприводу постійного струму трамвая, а також як
низькошвидкісний безредукторний електропривод трамвая нового покоління. Визначено найбільш перспективні
конфігурації магнітних систем з постійними магнітами для приводу трамвая. Шляхом варіації геометричних і
обмотувальних параметрів кожної з досліджуваних моделей електродвигунів, визначено механічні
характеристики, за яких досягається заданий момент і потужність у всьому діапазоні частоти обертання
ротора. Також виконано тепловий розрахунок з урахуванням міського їздового циклу високошвидкісних
двигунів у разі повітряного охолодження вентилятором і низькошвидкісних – в режимі рідинного
охолодження. Розрахунок характеристик досліджуваних електродвигунів виконаний у програмному пакеті
Simcentre MotorSolve. Бібл. 13, рис. 8, табл. 3
Ключові слова: чисельне моделювання, електродвигун, постійні магніти, електромагнітний момент, робочі
характеристики, тепловий розрахунок, електропривод трамвая.
Надійшла 24.05.2021
|
| id | techned_org_ua-article-189 |
| institution | Technical Electrodynamics |
| keywords_txt_mv | keywords |
| language | English |
| last_indexed | 2026-06-16T01:04:05Z |
| publishDate | 2021 |
| publisher | Інститут електродинаміки НАН України, Київ |
| record_format | ojs |
| resource_txt_mv | technedorgua/55/61856f335a1b9af760dd255999476b55.pdf |
| spelling | techned_org_ua-article-1892021-08-26T09:44:28Z COMPARATIVE ANALYSIS OF MAGNETIC SYSTEMS OF PERMANENT MAGNET MOTORS FOR TRAM ПОРІВНЯЛЬНИЙ АНАЛІЗ МАГНІТНИХ СИСТЕМ ЕЛЕКТРОДВИГУНІВ З ПОСТІЙНИМИ МАГНІТАМИ ДЛЯ ТРАМВАЯ Гребєніков, В.В. Гамалія, Р.В. Дадичін, С.А. numerical modeling electric motor permanent magnets electromagnetic torque performance characteristics thermal calculation electric tram drive чисельне моделювання електродвигун постійні магніти електромагнітний момент робочі характеристики тепловий розрахунок електропривод трамвая A numerical study of eight configurations of magnetic systems of electric motors with permanent magnets for driving a tram was carried out. The permanent magnet electric motor can be used as a high-speed electric drive to replace the existing DC electric drive of a tram, and as a low-speed gearless electric drive of a new generation tram. The most promising configurations of magnetic systems of electric motors with permanent magnets for tram drive have been determined. By varying the geometrical and winding parameters of each of the investigated models of electric motors, the mechanical characteristics are determined, at which the given torque and power are achieved in the entire range of the rotor speed. Also, a thermal calculation was performed taking into account the urban driving cycle of high-speed electric motors with air cooling by a fan and low-speed ones in liquid cooling mode. The calculation of the characteristics of the investigated electric motors was carried out in the Simcentre MotorSolve software package. References 13, figures 8, tables 3. Проведено чисельне дослідження восьми конфігурацій магнітної систем електродвигунів з постійними магнітами для приводу трамвая. Електродвигун з постійними магнітами може бути використаний як високошвидкісний для заміни існуючого електроприводу постійного струму трамвая, а також як низькошвидкісний безредукторний електропривод трамвая нового покоління. Визначено найбільш перспективні конфігурації магнітних систем з постійними магнітами для приводу трамвая. Шляхом варіації геометричних і обмотувальних параметрів кожної з досліджуваних моделей електродвигунів, визначено механічні характеристики, за яких досягається заданий момент і потужність у всьому діапазоні частоти обертання ротора. Також виконано тепловий розрахунок з урахуванням міського їздового циклу високошвидкісних двигунів у разі повітряного охолодження вентилятором і низькошвидкісних - в режимі рідинного охолодження. Розрахунок характеристик досліджуваних електродвигунів виконаний у програмному пакеті Simcentre MotorSolve. Бібл. 13, рис. 8, табл. 3 Інститут електродинаміки НАН України, Київ 2021-08-26 Article Article application/pdf https://techned.org.ua/index.php/techned/article/view/189 10.15407/techned2021.05.027 Tekhnichna Elektrodynamika; No. 5 (2021): TEKHNICNA ELEKTRODYNAMIKA; 027 ТЕХНІЧНА ЕЛЕКТРОДИНАМІКА; № 5 (2021): ТЕХНІЧНА ЕЛЕКТРОДИНАМІКА; 027 2218-1903 1607-7970 10.15407/techned2021.05 en https://techned.org.ua/index.php/techned/article/view/189/153 Авторське право (c) 2021 ТЕХНІЧНА ЕЛЕКТРОДИНАМІКА https://creativecommons.org/licenses/by-nc-nd/4.0 |
| spellingShingle | чисельне моделювання електродвигун постійні магніти електромагнітний момент робочі характеристики тепловий розрахунок електропривод трамвая Гребєніков, В.В. Гамалія, Р.В. Дадичін, С.А. ПОРІВНЯЛЬНИЙ АНАЛІЗ МАГНІТНИХ СИСТЕМ ЕЛЕКТРОДВИГУНІВ З ПОСТІЙНИМИ МАГНІТАМИ ДЛЯ ТРАМВАЯ |
| title | ПОРІВНЯЛЬНИЙ АНАЛІЗ МАГНІТНИХ СИСТЕМ ЕЛЕКТРОДВИГУНІВ З ПОСТІЙНИМИ МАГНІТАМИ ДЛЯ ТРАМВАЯ |
| title_alt | COMPARATIVE ANALYSIS OF MAGNETIC SYSTEMS OF PERMANENT MAGNET MOTORS FOR TRAM |
| title_full | ПОРІВНЯЛЬНИЙ АНАЛІЗ МАГНІТНИХ СИСТЕМ ЕЛЕКТРОДВИГУНІВ З ПОСТІЙНИМИ МАГНІТАМИ ДЛЯ ТРАМВАЯ |
| title_fullStr | ПОРІВНЯЛЬНИЙ АНАЛІЗ МАГНІТНИХ СИСТЕМ ЕЛЕКТРОДВИГУНІВ З ПОСТІЙНИМИ МАГНІТАМИ ДЛЯ ТРАМВАЯ |
| title_full_unstemmed | ПОРІВНЯЛЬНИЙ АНАЛІЗ МАГНІТНИХ СИСТЕМ ЕЛЕКТРОДВИГУНІВ З ПОСТІЙНИМИ МАГНІТАМИ ДЛЯ ТРАМВАЯ |
| title_short | ПОРІВНЯЛЬНИЙ АНАЛІЗ МАГНІТНИХ СИСТЕМ ЕЛЕКТРОДВИГУНІВ З ПОСТІЙНИМИ МАГНІТАМИ ДЛЯ ТРАМВАЯ |
| title_sort | порівняльний аналіз магнітних систем електродвигунів з постійними магнітами для трамвая |
| topic | чисельне моделювання електродвигун постійні магніти електромагнітний момент робочі характеристики тепловий розрахунок електропривод трамвая |
| topic_facet | numerical modeling electric motor permanent magnets electromagnetic torque performance characteristics thermal calculation electric tram drive чисельне моделювання електродвигун постійні магніти електромагнітний момент робочі характеристики тепловий розрахунок електропривод трамвая |
| url | https://techned.org.ua/index.php/techned/article/view/189 |
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