Abstract: IET Electric Power ApplicationsVolume 13, Issue 9 p. 1273-1279 Research ArticleFree Access Rotor design for line start AF-PMSM Mustafa Eker, Mustafa Eker Department of Mechatronics Engineering, Tokat Gaziosmanpasa University, Tokat, TurkeySearch for more papers by this authorMehmet Akar, Corresponding Author Mehmet Akar [email protected] Department of Mechatronics Engineering, Tokat Gaziosmanpasa University, Tokat, TurkeySearch for more papers by this authorCem Emeksiz, Cem Emeksiz Department of Electrical and Electronics Engineering, Tokat Gaziosmanpasa University, Tokat, TurkeySearch for more papers by this authorZafer Dogan, Zafer Dogan orcid.org/0000-0002-7953-0578 Department of Electrical and Electronics Engineering, Tokat Gaziosmanpasa University, Tokat, TurkeySearch for more papers by this author Mustafa Eker, Mustafa Eker Department of Mechatronics Engineering, Tokat Gaziosmanpasa University, Tokat, TurkeySearch for more papers by this authorMehmet Akar, Corresponding Author Mehmet Akar [email protected] Department of Mechatronics Engineering, Tokat Gaziosmanpasa University, Tokat, TurkeySearch for more papers by this authorCem Emeksiz, Cem Emeksiz Department of Electrical and Electronics Engineering, Tokat Gaziosmanpasa University, Tokat, TurkeySearch for more papers by this authorZafer Dogan, Zafer Dogan orcid.org/0000-0002-7953-0578 Department of Electrical and Electronics Engineering, Tokat Gaziosmanpasa University, Tokat, TurkeySearch for more papers by this author First published: 05 March 2019 https://doi.org/10.1049/iet-epa.2018.5579Citations: 5AboutSectionsPDF ToolsRequest permissionExport citationAdd to favoritesTrack citation ShareShare Give accessShare full text accessShare full-text accessPlease review our Terms and Conditions of Use and check box below to share full-text version of article.I have read and accept the Wiley Online Library Terms and Conditions of UseShareable LinkUse the link below to share a full-text version of this article with your friends and colleagues. Learn more.Copy URL Share a linkShare onFacebookTwitterLinkedInRedditWechat Abstract This study presents design and performance analyses for a new line start axial flux permanent magnet synchronous motors (AF-PMSMs). The innovative part of this study is that AF-PMSM can start directly from the line and operate with high efficiency and power factor after synchronisation. Prototype manufacturing was carried out after completing the analytical and electromagnetic designs for the targeted motor. The synchronisation capacity, power capacity, power–speed characteristic, power-efficiency relationship along with the total harmonic distortion and back-emf waveform of the induced voltage have been examined for the prototype motor. Simulation studies have been verified experimentally. The results obtained were compared with an induction motor with the same power. It was observed as a result of the work carried out and a line start AF-PMSM is obtained that is 4–10% more efficient in comparison with an induction motor having the same power. 1 Introduction Electrical motors and the systems have a significant share in energy consumption and they comprise more than 40% of the electricity consumption [1-3]. This ratio in Europe reaches 70% for industrial production processes [2]. This issue related to electrical motors has forced producers/users to produce/use motors that are more efficient. The importance of electrical motors with regard to energy consumption has brought about related legal regulations, thus standards have been set for motors. The motors used were classified according to how they start their areas of use and their efficiencies [2, 3]. Even though induction motors are ranked first with regard to the usage ratios of electrical motors, there are also various applications in which the use of these motors is limited. In addition, high-energy consumption resulting from the extensive industrial use of induction motors with efficiencies of about 80% drive consumers to seek motors that are more efficient. High efficiency in motors can be attained by way of magnets that eliminate winding losses. The use of new generation motors with a fixed magnet structure has increased with the advent of magnet technology. In recent years, permanent magnet synchronous motors (PMSMs) are widely preferred in the industry especially as servo systems because of their advantages such as high efficiency, high power density, the ability to operate at variable speeds, volume–weight ratio, higher efficiency when compared with induction motors, formal compatibility with the applications, the ability to operate at high speeds and their conformity to speed control [4-6]. PMSMs are manufactured at different topologies. Axial flux (disc type) synchronous motor (AFSM) is one of these topologies. In this structure, magnetic flux passes directly from the air gap axially. In these types of motors, while rotor is manufactured disc, stator is manufactured ring structure. AFSMs are among the most frequently studied topics in recent years due to their flat structure, high torque volume ratios, high-efficiency values, power density, moment densities and so on [7-10]. In addition, axial flux PMSM (AF-PMSM) may be categorised with regard to production type as single stator single rotor, single stator double rotor, double stator single rotor and multi-stator multi-rotor. In addition, topologies can be classified according to whether the magnets are surface-mounted or embedded, whether the stator core is slotted or not. AF-PMSM topologies are classified among themselves according to core shape, slot structure, coil structure and the positioning of the magnets. AF-PMSM topologies have advantages and disadvantages when compared with other topologies [11-16]. In addition, studies have also been carried out on various parameters such as back-emf induced in AFSM [16-18], cogging torque [19, 20] and torque ripple [21]. The fact that AFSMs cannot line start is among the major disadvantages. For this purpose, drivers with high capabilities are required. There is a need for either highly capable drivers or position sensors for these motors to start or they can start by line of a change in their rotor design. The first study for line-start AF-PMSM's was carried out by Mahmoudi et al. [22]. They placed a short-circuit ring on the internal diameter of the rotor disc encompassing the inner stator yoke for direct line-start. Non-slotted solid rotor was used with direct line start feature provided to the motor via the interaction of the magnetic field generated by the eddy current induced in the short-circuit ring and the air-gap rotating magnetic field. Two different designs were presented in another study by the researchers [23] as non-slotted and cageless solid rotor and composite rotor. Two different rings were added to the internal and external radii of the rotor disc. The composite rotor was coated with a 0.05 mm thick copper layer and three-dimensional (3D) finite-element analysis (FEA) was performed. It was observed based on the acquired results that both the synchronisation ability and starting torque of the composite road increased at a statistically significant level in comparison with the solid rotor. While the thin copper surface coated on the rotor ring increased the electrical conductivity of the material, it also enabled the rotor to start faster in addition to synchronising faster. The same researchers produced a solid rotor AF-PMSM prototype in another study [22]. It was concluded in this study that the prototype generates a high starting torque and is suited for high-performance applications but that re-synchronisation issues developed in the motor in cases of asynchronism at loads greater than the nominal load and at high speeds. Today, superior behaviours are expected from industrial motors such as stable reaction against sudden loads, instantaneous acceleration, ability to operate at low/high speeds, low energy consumption, low solid/high power and so on. Significant deficiencies are observed in meeting the superior demands of the industry when the aforementioned studies on AF-PMSMs are examined. The objective of this study was to line start an AFSM by adding a squirrel cage to the rotor while ensuring high efficiency and power factor. In accordance with the targeted values, a line-start AFSM was designed with 5.5 kW shaft power, nominal speed of 1500 rpm with an IE4 energy class and a prototype motor has been manufactured after electromagnetic, thermal and structural analyses. Synchronisation capacity of the prototype motor, its load speed characteristic, power efficiency relations in addition to back-emf and total harmonic distortion (THD) have been examined. Experimental results have verified the simulation work carried out during the study. A motor with a power factor of 0.98 and efficiency of 92.92% has been obtained as a result of the study with super premium efficiency (IE4) class. The designed hybrid motor is compared with two different motor groups. IEC 600034-30-1 standard was taken as the basis for determining these two groups. The qualifications of the prototype motors for eigenvalue and widespread impact are: the designed motor can be connected to line directly because of new rotor topology and can be a more efficient alternative for the induction motors especially in fixed speed applications. Due to line start and operating synchronous speed capabilities, prototype motor does not need the high quality and high-cost motor drives and position sensors and being compared to the radial flux motors, it will provide a high-performance modular structure with the modules that are aligned in axial way. The presented study is comprised of five sections. Section 1 is the introduction. General information on line start AF-PMSM was provided in Section 2. Final design and prototype production information are included in Section 3. Section 4 includes results and discussion. Conclusion is the final section. 2 Line start AF-PMSM 2.1 Suggested AF-PMSM AF-PMSMs are manufactured in different topologies. These topologies have different names according to the number of stator and rotors, stator slot structure, positioning of the magnets and the winding structure [23, 24]. The classification according to the number of stator and rotors is the most frequently used classification [10]. Fig. 1 shows the generalised display for AFSM [25]. Fig. 1Open in figure viewerPowerPoint Generalised display for AFSM , , , g and h in the figure represent stator outer diameter, internal diameter, stator effective length in the radial direction, airgap length and stator number, respectively [25]. In this study, single-sided AF-PMSM structure has been used which is accepted as the simplest structure. This structure is comprised of a single stator and a single rotor. This structure is compact and has a high torque capacity. Therefore, they are frequently preferred especially in military transport systems, servo electromechanical drivers and gearless elevator systems [5, 11]. Fig. 2 shows the line-start AF-PMSM visual. Fig. 2Open in figure viewerPowerPoint Model of the generated architecture Fig. 2 shows the stator core (1), magnets (2), squirrel cage (3) and rotor core (4) FEA models for the designed motor. 2.2 Line start AF-PMSM analytical and FEA design An electrical motor has to first go through the analytical design, electromagnetic design, structural design and thermal design stages before it can be manufactured. Line-start AF-PMSM design is based on general AF-PMSM topology. However, the squirrel cage rotor design criteria should also be taken into consideration due to the hybrid structure of the designed motor [25]. Due to the AF-PMSM geometry, the actual result cannot be obtained at 2D FEA solutions [26]. Therefore, 3D FEA solutions have been made during the FEA design of the designed AF-PMSM. ANSYS Electromagnetics Suite 16.0 software was used for detecting the magnetic circuits, power densities and circuit parameters of AF-PMSM [27]. In this study, line start AF-PMSM has been targeted with a power factor of 0.94 and efficiency of 94%, four poles and a shaft power of 5.5 kW that operates at a speed of 1500 rpm. First of all, the analytical design of the motor was made after which the electromagnetic design was completed. Electromagnetic design was completed by making changes in parameters such as stator–rotor dimensions (diameter-thickness), magnet thickness, magnet embrace and air gap length. Finally, structural and thermal designs were carried out via FEA [27]. Targeted values were reached in the analytical, electromagnetic, thermal and structural designs of the line start AF-PMSM [27]. The motor prototype was manufactured in accordance with the results obtained from the analytical and FEA calculations. Table 1 includes the values for the prototype to be manufactured. Fig. 3 shows the visual for line start AF-PMSM. Table 1. Analytical and FEA design data for the line start AF-PMSM to be produced Motor parameters Value Unit stator outer diameter 0.248 m stator inner diameter 0.132 m stator current 9.03 A number of conductors per slot 38 — connection star — back-emf 198 V line surge current density 21000 A/m magnet axial length 4 mm number of poles 4 — permanent magnet segments/pole 5 — sum of stator thickness (yoke + slot thickness) 60 mm sum of rotor thickness (yoke + slot thickness) 38 mm number of stator slots 36 — number of rotor cage slots 28 — wire diameter 1.151 mm2 number of strands 2 — axial air gap length 1 mm armature phase resistance 0.96 Ω squirrel cage resistance 1.06 Ω armature leakage reactance 2.082 Ω rotor leakage reactance 0.919 Ω power factor 0.936 — output power 5460 W input power 5862 W efficiency 93.14 % electromagnetic torque 35.01 Nm Fig. 3Open in figure viewerPowerPoint Model of the created architecture (a) Item 1 depicts stator core and item 2 shows stator windings, (b) Items 3,4 and 5 represent the magnets, short circuit cage and rotor core, respectively. Fig. 3 shows the quarter model of the manufactured motor. In Fig. 3a, stator core is depicted by item 1, whereas stator windings are shown by item 2. Items 3, 4 and 5 represent the magnets, short circuit cage and rotor core, respectively in Fig 3b. 3 Prototype manufacturing The suitable motor dimensions for the prototype were determined by considering the transient state values and the values after synchronisation. Many parameters such as motor stator currents, torque curves, acceleration curves, magnetic saturations were compared when making this selection. The prototype production for the line start AF-PMSM was carried out with the same methods used for the traditional AF-PMSM. A different type of production was used only for the rotor production due to the hybrid structure of the motor. The rotor was made of mass steel, while the rotor slots were made by grooving the mass steel, whereas the squirrel cage was made of aluminium. The axial rotor was placed on the cast formed after which the prepared aluminium cast was poured on it. Steel and cast aluminium were processed on the lathe workbench thus taking on their final form. Afterwards, the split magnets were installed on the rotor and squirrel cage bars. Table 2 shows the materials used for producing the prototype motor, while Fig. 4 shows the motor pictures. Table 2. Material type of line start AF-PMSM part Line start AF-PMSM part Material stator JFE_20JNEH1500 rotor steel 1010 magnet N45-SH stator windings copper squirrel cage aluminium Fig. 4Open in figure viewerPowerPoint Line start AF-PMSM pictures (a) Stator, (b) Rotor 4 Results and discussion 4.1 Simulation results The motor was operated for 1.8 s under dynamic conditions for the FEA analyses of the designed line start AF-PMSM. Various parameters for the motor were obtained such as three-phase currents, electromagnetic torque, speed, efficiency and power factor. Inertia moment value is another variable that should be taken into consideration for line start motors. Total inertia value for the motor and load is of critical importance in order to ensure that the motor is synchronised and that it starts at the required amount of time. While inertia moment was calculated analytically as 0.11615348 kgm2, a value of 0.10902735 kgm2 was obtained via the software used. As can be seen, the values are very close. The value calculated by Maxwell was taken as a reference during analyses via FEA and the per unit values were increased from 1 to 2.0 p.u in increments of 0.1 p.u while examining the motor starting capacity via FEA. Fig. 5 shows the FEA analysis results carried out for determining the safe inertia range for the presented motor. It can be observed upon examining the graph that the motor could reach synchronous speed until 1.4 p.u after which it failed to synchronise. An inertia moment value of 1 p.u. was taken as a basis in simulation and experimental studies. Fig. 5Open in figure viewerPowerPoint FEA analysis results of different inertia moments Fig. 6 displays a phase current graph, torque graph and speed graph for the motor operated for 1.8 s under the full load at ANSYS Maxwell operating at a rate of 1500 rpm with time intervals of 0.001 s [27]. Fig. 6Open in figure viewerPowerPoint Graphs for the FEA results (a) One phase current of stator, (b) Torque, (c) Speed [27] It can be observed upon examining the graphs that the rms value of the stator A phase current was 60.49 A at the start which was obtained as 10.43 A after reaching the synchronous speed. The electromagnetic torque is greater than the load torque in the torque curve until the motor reaches the synchronous speed. Even though negative peaks are observed in the torque under transient state, the average torque in the transient state is positive and 57.12 Nm on average, while the average torque value is 35.26 Nm after reaching the synchronous speed. It is observed in the motor speed graph that the motor reaches synchronous speed in a short time of 1.2 s. It has also been observed that there are oscillations in the transient state in the speed curve. The motor has reached a maximum value of 1675 rpm. After this value, the motor reached synchronous speed despite the fact that there was an oscillation of 253 rpm in rotor speed. Detailed information can be found in [27] for FEA analysis of the suggested topology. 4.2 Experimental results A test setup was prepared for testing the performance of the prototype motor. Various motor parameters such as motor three-phase current, power factor, motor speed, motor shaft, input power, load torque can be recorded with the prepared test setup. Fig. 7 shows the setup used for the experimental studies on the prototype motor of line start AF-PMSM. Fig. 7Open in figure viewerPowerPoint Test bench The test setup was manufactured to allow the coupling of two different motors. The prototype motor numbered 1 in Fig. 7 was assembled onto the motor via a coupler (numbered 2) and bearing (numbered 3). The dc motor in photo 4 was operated in torque control mode thereby carrying out the motor loading. The load cell numbered 5 was used for torque measurement. While the encoder numbered 6 was used to acquire speed data. The driver has a programmable input/output, harmonic filtering and Modbus protocol on Ethernet physical connection structure. Data transfer is carried out via Ethernet at a rate of 10 Mbit/s. 4.2.1 Synchronisation capability Different starting shaft torque values were applied on the motor shaft to test the synchronisation capability. First, the motor was operated with no load after which different shaft torque values up to the nominal torque value (35 Nm) was applied and the start graphs of the motor were acquired. Fig. 8 shows the start graphs of the motor at three different shaft torque values. In addition, Fig. 9 compares the FEA and experimentally determined acceleration curves when 35 Nm torque is applied on the motor shaft. Fig. 8Open in figure viewerPowerPoint Rotor speed curve at experimentally different shaft torques Fig. 9Open in figure viewerPowerPoint Comparison of the rotor speed curve experimental and FEA results when 35 Nm shaft torque is applied It can be seen in Fig. 8 that the motor has reached maximum speed under no load in 0.51 s and the synchronous speed in 0.91 s. The motor reaches maximum speed in 0.58 and synchronous speed in 1.05 when 50% of the nominal shaft torque is applied on the motor shaft. The motor reaches maximum speed in 1.015 s and synchronous speed in 1.3 s at full shaft torque value. The average speed value was 1500 rpm at all shaft torque values after the motor reached synchronous speed. In addition, even though the FEA and experimental results for the shaft torque applied on the motor shaft differ during start, the synchronisation times are similar. The motor is synchronised in 1.4 s according to both the experimental and FEA analysis results. The motor was started by applying 44 Nm load value on the motor shaft after which its synchronisation capability was examined. The motor could not synchronise at this value and the speed oscillated between 1427 and 1194 rpm as can be seen in Fig. 10. The motor successfully synchronised up to the nominal load value, however it could not synchronise above the nominal load. Fig. 10Open in figure viewerPowerPoint Rotor speed graph at 125% nominal shaft load 4.2.2 Break down torque The objective is to determine the torque value at which the line start AF-PMSM strays off from the synchronous speed after a shaft torque is applied. In this experiment, the motor is first operated with no load, after which the shaft torque value applied on the motor shaft was gradually increased by values of 2 Nm. The values obtained as a result of this experiment are displayed in Fig. 11. Fig. 11Open in figure viewerPowerPoint Break down moment results: torque–speed graph The motor was first operated with no load and the torque applied on the shaft was increased gradually by 2 Nm until it reached the value of 48 Nm. It was observed in Fig. 11 that there was no straying from the synchronous speed even when the nominal load applied on the motor shaft was 140%. In other words, the motor did not stray from the synchronous speed value despite a shaft load of 7.5 kW. The average rms value drawn by the stator windings was measured as 12.4 A. The shaft torque applied was stopped at this value to avoid the damaging of the windings and magnets. 4.2.3 Sudden load change test In this experiment, changes that may occur in the synchronous speed of the motor were examined due to sudden changes in the torque values applied on the motor shaft. The torque applied on the shaft was suddenly increased/decreased after the motor was operated at the nominal torque value. The torque value applied on the shaft was suddenly dropped down to 25 Nm after the motor was operated with a nominal shaft torque applied on the motor shaft. Afterwards, a nominal torque value was reapplied on the motor shaft. The torque value applied on the motor shaft was then suddenly increased up to 40 Nm. The changes that take place in rotor speed in these instances were examined. The graphs obtained have been shown in Fig. 12. Fig. 12Open in figure viewerPowerPoint Speed graph for the sudden load change applied on the shaft The sudden shaft torque changes (increase/decrease) on the motor shaft indicated that the rotor did not stray off from the synchronous speed. Highest oscillations caused by shaft torque changes were observed when the applied torque was dropped from 40 Nm to 0. An oscillation of 80 rpm was observed. These oscillations are momentary and did not result in any stray from the synchronous speed. 4.2.4 Back-emf test and THD There is a direct relation between the manufactured electromagnetic torque and back-emf. For this test, the line start AF-PMSM was operated in generator mode and the voltage induced at the winding at no load was measured when it was rotating at a speed of 1500 rpm. The acquired values have been given in Fig. 13. Fig. 13Open in figure viewerPowerPoint Waveforms of the voltage induced in the windings Fig. 13 shows the waveforms for the voltage induced in the windings for a period of 0.1 s. It was observed upon examining the graphs that a sinusoidal wave has been obtained with a maximum value of 297.54 V and a phase difference of 120°. Although, the shape of the voltages induced at the windings were similar to each other and sinusoidal, harmonics were observed in waveforms. Therefore, the THD value that took place in the signals was also examined. Fig. 13 shows the THD value for the voltage signals induced. The THD graph in Fig. 14 has three fundamental aspects. These are fundamental component, harmonics and unconsidered DC and noise signals. It is observed that the fundamental component is generated at 50 Hz which is the operating frequency of the motor and that the harmonics are generated at the second, third, fourth, fifth and sixth levels of the fundamental component. The THD value at these signals was calculated as −20.59 dB. The THD value at the signal was obtained at 9.73%. Fig. 14Open in figure viewerPowerPoint THD graph for the induced voltage 4.2.5 Performance curves The performance curves of the line start AF-PMSM were provided comparatively with the results acquired via FEA. Line start AF-PMSM was experimentally operated by applying a shaft torque of 35 Nm until the thermal regime was reached and the experimental study was carried out afterwards. A load of 6 kW was applied on the shaft of the line start AF-PMSM at certain intervals and the current, efficiency and power factor values of the line start AF-PMSM were examined. In FEA, the performance curves were acquired via Electric Machines Design Toolkit of the used software. The toolkit allows for the computation and display of torque–speed curves and efficiency maps for electric machines. It integrates various effects such as skewing, DC/AC winding resistance, end-turn winding inductance, frequency-dependent core loss coefficients and mechanical loss. Mechanical and ventilation losses in FEA were taken as 1.2%*Pshaft (4 poles machines) which is also used in design standards while additional losses were taken as 0.5%*Pshaft (include friction and other additional losses). The acquired values have been given in Figs. 15-17. Fig. 15Open in figure viewerPowerPoint Comparison of the efficiency values acquired via FEA and through experiments Fig. 16Open in figure viewerPowerPoint Comparison of the power factor values acquired via FEA and through experiments Fig. 17Open in figure viewerPowerPoint Comparison of the stator current average rms values acquired via FEA and through experiments It is indicated in Fig. 15 that the difference between the electromagnetic and experimental results decreases with increasing torque applied on the shaft. Efficiency was obtained as 92.92% as a result of the experiments when the shaft power of the prototype motor was 5.5 kW; whereas it was 93.13% in the results obtained via FEA. It has been observed according to the experimental results that the prototype motor has operated at an efficiency of 91.5% starting from an output power of 2.8 kW. After this power value, average efficiency was calculated experimentally as 92.54%, whereas it was 93.54% according to FEA results. Differences were observed between the experiment and FEA results at values with lower shaft power. This is due to the various approaches applied during FEA analysis and differences in manufacturing. According to Fig. 16, instances when the prototype motor shaft power is 100% are close to the ohmic operating region both experimentally and according to electromagnetic results. Although experimentally the power factor is 0.971 at full load, it has been calculated as 0.989 according to the analysis results. It is observed that the difference between the results acquired via experiments and FEA decrease with increasing motor shaft power. Although experimentally an average power factor of 0.96 was obtained at 50% of the nominal load and higher, the power factor value for the same loads was 0.97 according to the FEA results (Table 3). Table 3. Comparison of the FEA and experimental results for line start AF-PMSM at nominal load Result Current, A Power factor Efficiency, % FEA 9.03 0.989 93.13 experimental 9.02 0.971 92.92 In Fig. 17, average values of three-phase rms currents show that while the prototype motor experimentally draws a current of 9.02 A at full load, a current of 9.03 A was obtained during the FEA analysis. No significant differences were obtained according to the graph between the experimental and FEA curves. In general, experimental results are matched with the FEA. The average value for the stator currents was in general equal and a difference of 0.01 A was observed at the nominal load value. A difference of 0.018 in power factor and a difference of 0.21% in efficiency were observed at the nominal load value The fact that the motors used and manufactured in our day have different efficiency values has brought about the necessity for various legal regulations. Production of low-efficiency motors has been prohibited according to the rules set forth by IEC. Efficiency classification has been placed under a different title. One of these is the line start TS EN 60034-30-1 motors category within the scope of TS EN 60034-30-1. The prototype motor has a structure which can be an alternative to the motors in this standard. Therefore, the prototype motor is compared in Table 4 with an induction motor with the same power that is used in the industry within the scope of IEC 60034-30-1. Table 4. Comparison of prototype AF-PMSM and induction motor Induction motor_1 Induction motor_2 Prototype AF-PMSM rated current, A 11.2 11.0 9.02 power factor 0.81–0.83 0.81–0.85 0.971 efficiency, % 87.7 89.6 92.92 efficiency classes of line operated AC motors IE2 IE3 IE4 It can be observed from Table 4 that the prototype motor has better values in comparison with the traditional induction motor. In addition to these values, the ratio of the start currents to the rated current was 7 for the induction motor, whereas this value has been obtained as 5.8 for the prototype motor. In general, the prototype motor operates with a lower current, higher power factor and efficiency at the rated values. 5 Conclusion In this study, a hybrid AF-PMSM design was completed which can line start like an induction motor in the transient state and operate with high efficiency and power factor at the transient state. The results acquired via FEA have been verified experimentally. All experiments have yielded successful results except the inability to synchronise when the load applied to the rotor of the prototype motor was above the nominal load value. The values acquired via FEA have been verified experimentally and similarities were observed. When the current studies carried out for PMSMs are examined, it can be observed that there are studies on line start for radial flux types and driver start for axial flux types. With this study, a hybrid structure has been developed and the manufactured prototype has reached the desired values. A design that can be an alternative to current motors especially in applications such as fan, pump and elevator applications has been acquired. The fact that the line start AF-PMSM designed falls under the IE4 efficiency class during this period when it is emphasised that higher efficiency motors should be preferred has increased the importance of this study further. 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Publication Year: 2019
Publication Date: 2019-01-22
Language: en
Type: article
Indexed In: ['crossref']
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Cited By Count: 8
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