Fig 11 - uploaded by Dahaman Ishak
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Stators and rotor of 12-slot/10-pole motors. (a) Stator with coils on all teeth, (b) stator with coils on alternate teeth, and (c) rotor. f Br (r) = 1 + R s r 2
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The electromagnetic performance of three-phase permanent magnet brushless motors in which the slot and pole numbers are similar and either all the teeth or only alternate teeth carry a concentrated coil is compared. Analytical and finite element techniques are employed to predict the air-gap flux density distribution, the cogging torque, electromot...
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Citations
... These machines also do not suffer from large cogging torque, so skewing is not necessary [20]. Furthermore, the concentrated windings reduce the mutual inductance between phases and so improve the fault tolerance of these machines [21]; this is of greatest effect when the coils are wound about only alternate teeth (single layer) as opposed to every tooth (double layer) [22]. However, these machines come with a substantial disadvantage in that the simple winding structure results in a large number of unwanted magneto-motive force (MMF) harmonics in the air-gap [23]. ...
... As a second converter is already the convention in offshore wind power, all the machines investigated at the 3 MW scale are also dual threephase ones. It has been demonstrated extensively in the literature that single-layer FSCW machines suffer from much higher rotor and PM eddy current losses than double-layer FSCW machines [22,25]. As the principal aim of this work is to reduce the rotor and PM eddy current losses, FSCW machines with single-layer windings are not considered. ...
... The common 12s/10p machine was selected as the initial FSCW machine for investigation at the 3 MW level. It is evident from the literature that a double-layer winding exhibits a much larger reduction in armature MMF harmonics and so reduced rotor loss when compared with a single-layer winding [22]. As this is a principal concern with the move to an FSCW, a double-layer winding was chosen. ...
This paper investigates the use of fractional-slot concentrated windings (FSCWs) in large-scale (MW level) offshore wind generators. It focuses specifically on a power rating of 3 MW and uses an existing direct-drive synchronous PM machine (DD-SPM) with 480s/160p and dual three-phase integer-slot winding (ISW) as a baseline. A multiple of the common 12s/10p FSCW machine is used that matches the electrical frequency of the ISW machine, yielding a 192s/160p dual three-phase machine. The hybrid star–delta connection has grown increasingly popular owing to its unique harmonic cancellation properties, which can help reduce rotor and PM eddy current losses in FSCW machines. In this paper, two dual three-phase star–delta-wound machines are scaled to 3 MW and included in the investigation. Specifically, a 384s/160p dual three-phase and dual star–delta winding machine, which is a multiplication of the 24s/10p machine, and a 192s/176p dual three-phase and dual star–delta winding machine, which is a multiplication of the 24s/22p machine, are used. These machines are investigated using finite element analysis (FEA) and compared on the basis of their air-gap flux density harmonics, open-circuit electro-motive force (EMF), torque performance, and losses and power. It is found that the proposed 384s/160p dual star–delta winding machine has the best electromagnetic performance of all, with a stator power that is 1.2% greater than that of the baseline ISW machine. However, this machine has a coil pitch of 2 and so loses the manufacturing and fault-tolerant advantage of having concentrated windings. If concentrated windings are desired, then the proposed 192s/176p dual star–delta winding machine is the best choice, with the stator power only 2.6% less than that of the baseline ISW machine, but unfortunately still has significant rotor and PM eddy current losses.
... It is feasible to prepare the fractional slot windings with various numbers of slots and poles combinations. But slot/pole combinations of 2p = Q −1 or 2p = Q − 2 are the best because of lower rotor losses and torque ripple [14,[34][35][36][37][38][39][40]. Accordingly, here, as shown in Fig. 1, some dissimilar 3-phase FSCW with various slot/pole numbers are considered. ...
... When the spatial distribution of the armature winding is known, the rotating MMF produced by the applied current can be described using the Fourier series function. The MMF distribution for various winding types including concentrated winding and distributed winding topology has been widely studied in many literatures [30][31][32][33] as a general expression. Such the general function is modeled through the following equation: ...
A new analytic model for calculating of the air‐gap flux density (AGFD) of surface‐mounted permanent magnet synchronous machines (SMPMSMs) is presented. This proposed model is capable to taking into account the effects of magnetic saturation, armature reaction and stator slots opening. Furthermore, the real form of air‐gap distribution and spatial distribution of flux density of the PM poles are considered. The armature reaction effect is modeled using phasor diagram analysis of the motor as a function of the load torque, the armature current amplitude, power factor and the inverse air gap length. Also, saturation phenomenon predicted using the new non‐linear proposed function in connection with the armature reaction effects and the properties of the lamination material. It is shown that the proposed model capable to predicting acceptably the air gap flux density waveform of the SMPMSMs at lagging and leading power factors and with the load torque variation. The presented analytical approach is verified by the two‐dimensional finite‐element analysis (FEA) results.
... The conventional double-layer winding machines were presented as poor candidates for independent operation and control due to higher mutual coupling between the phase winding since each slot contains two coil sides. Whereas double-layer winding provides the benefits of low harmonic content in EMF, low torque ripples, and lower losses [15]. An attempt has been made with non-overlapped double-layer winding in a modular three-phase machine to provide a smaller mutual inductance [16]. ...
This paper proposes a three-phase dual-winding permanent magnet synchronous machine (PMSM) providing multitasked operation for accessory drive systems in hybrid electric vehicles (HEV). The novelty of this research lies in the machine having special slots and pole combinations with specific configuration of two sets of double-layer concentrated group winding separated by the unwound tooth between the phase groups formed on the same stator to achieve both the motoring and generator operation simultaneously as well as independently. These operations are accomplished by incorporating motor and generator winding separately on the same stator of a single PMSM machine. This single machine is particularly designed to eliminate the mutual coupling between these two sets of windings such that the load variation on the generator does not affect the mechanical output power of the motor. To confirm this multitasking, the electromagnetic design of the machine has been presented, and its operating modes are analyzed. The performance is compared using finite element analysis with that of a conventional PMSM machine having a double-layer winding configuration.
... It is possible to design fractional-slot windings with too many different combinations of numbers of poles and slots [14,[34][35][36][37][38][39][40]. But here, in order to take into account the effects of slot numbers and winding topologies on the MMF and consequently, electromagnetic performance, five famous windings with the pole numbers equal to 10 are of concern. ...
Fractional‐slot concentrated‐windings are appreciated for their simple construction, short end‐winding length, high copper fill factor, low cogging torque, good field‐weakening capability and fault‐tolerant ability. However, in comparison to the conventional distributed windings, the fractional‐slot concentrated‐windings are characterised with high space magnetomotive force (MMF) harmonics, which results in undesirable effects on the machine performance, such as localised core saturation, eddy current loss in the rotor and noise and vibration. In order to improve winding characteristics, several techniques have been developed recently. This manuscript introduces the 5 new winding topologies by using the general concept of stator slot shifting. It means that, in order to cancel undesirable MMF harmonics, by doubling (or tripling or even multiplying) the slot number and dividing the winding and then relatively shifting the winding by one (or more) slots, the undesirable harmonics have been eliminated effectively. The best choice is chosen according to the lowest amount of the MMF harmonic, highest value of winding factor and torque desirable characteristics. At the end, comprehensive comparisons for the designed synchronous reluctance motor (SynRel) equipped with proposed windings and also distributed winding are presented. The analytical study and 2D FEM analysis results show that it is possible to get an ideal low space‐harmonic winding topology, and consequently, a low torque ripple for these motors.
... The main purpose of magnetic isolation is to pursue low mutual inductance between faulty and healthy windings [23,24]. In the presence of fault operation, fault winding could put the healthy winding at risk by induced voltage derived from the fault current. ...
Permanent magnet synchronous machines provide many dramatic electromagnetic performances such as high efficiency and high power density, which make them more competitive in aircraft electrification, whereas, designing a permanent magnet starter–generator (PMSG), with given consideration to fault tolerance (FT), is a significant challenge and requires great effort. In this paper, a comprehensive FT PMSG design process is proposed which is applied to power systems of turboprops. Firstly, potential slot/pole combinations were selected based on winding factor, harmonic losses and manufacture issues. Then, pursuing high power density, a multiple objective optimization process was carried out to comprehensively rank performances. To meet a fault tolerance target, electrical, magnetic and thermal isolation topologies were investigated and compared, among which 18 slot/12 pole with dual three-phase was selected as the optimal one, with a power density of 7.9 kW/kg. Finally, a finite element analysis verified the performance in normal and post-fault scenarios. The candidate machine has merits concerning high power density and post-fault performance.
... It is noted that for the original 12-slot/10-pole and 14-pole machines (2p = N s � 2) as shown in Figure 2, there are no significant differences in the stator windings apart from the phase sequences. Consequently, it is expected that the resultant electromagnetic performances for the two 12-slot machines could be very similar in their dual 3-phase configurations [25][26][27][28]. However, in this study, it will be shown that for the 24-slot dual 3-phase machines, the resultant electromagnetic performances could be significantly different, especially on one group of 3-phase faulty conditions. ...
... From Figure 6, it can be seen that the 14-pole PM machine has slightly larger back-EMF amplitudes than the 10-pole machine. This is because the 14-pole machine has a larger rotor outer diameter than the 10-pole machine [28], Table 1. ...
... Besides, the FEApredicted torque and torque ripple with current variation are also obtained and shown in Figure 8. Due to the relatively larger back-EMF as shown in Figure 5, the resultant torque output is also larger for the 14-pole machine, Figures 7-8. It can be further seen that the torque pulsations on healthy conditions are quite small and mainly at the 12th harmonic, Thus, the torque ripple (%) for the PM machine can be described as [28,29]. ...
In this study, the electromagnetic performances of dual 3‐phase permanent magnet (PM) machines with coil span of two slot‐pitches are comparatively investigated. It mainly focuses on two PM machines with different slot/pole number combinations (Ns/2p), that is, the 24‐slot/10‐pole and 24‐slot/14‐pole machines (2p = Ns/2 ± 2). First, winding configurations are illustrated for these two dual 3‐phase machines with 30° angle displacement. Then, the winding factor, back electromotive force, average torque, torque ripple, iron and PM losses, short‐circuit (SC) current, and PM irreversible demagnetisation are analysed and compared for both machines on the conditions of healthy operation and one set of three‐phase fault, that is, SC or open circuit (OC), respectively. The comparative results show that on healthy condition the 14‐pole PM machine has a slightly larger torque output. Besides, on 3‐phase OC condition, the 14‐pole machine also performs better over‐rating torque capability. In terms of iron and PM losses, the 10‐pole machine has smaller iron losses but larger PM losses than the 14‐pole machine. Moreover, on 3‐phase SC condition, the 14‐pole machine has a significantly lower risk of PM irreversible demagnetisation than the 10‐pole machine, although both machines have very similar SC currents. Finally, the 24‐slot/10‐ and 14‐pole dual 3‐phase PM machines are both prototyped and some tests are carried out for validation.
... Both designs consist of identical stator/rotor pole number combination, i.e., 12 stator-slot/10 rotor-pole (12s/10p) and same concentrated non-overlapping winding topology. Therefore, the corresponding phase vectors and winding arrangement for both motor topologies are depicted in Fig. 7. Since there are two coil sides in one stator slot, such type of winding arrangement is referred to as a double-layer (DL) winding [20]. The major difference between the two motor topologies investigated is the rotor configurations. ...
... A dual three-phase 12s/10p IPM motor with single layer winding is shown in Fig. 13(a), which only has one coil side in one stator slot. This type of winding layout is commonly adopted in the safety-critical applications, giving the benefit in physical, electromagnetic and thermal separation between phases [20]. Converting the winding layout from double layer to single layer which halves the number of phase vectors as shown in Fig. 13(b). ...
Electric power steering (EPS) plays a critical role towards safety and comfort especially for modern vehicles with ever-increasing complexity. The evolution of EPS technologies require not only vehicle dynamics and fuel efficiency but also higher standards of steering function. Apart from providing essential electromechanical energy conversion, the performance of EPS motor has received attention from industry and academic community in terms of high torque/power density and low level of noise and vibration. This paper details aspects of design and analysis of permanent magnet synchronous motor (PMSM) for EPS application. Furthermore, the concept of multi-phase motor is adopted factoring redundancy design in achieving fail-operational for safety critical applications such as steer-by-wire (SbW) system for autonomous driving. The motor topologies investigated have been modelled utilising Motor-CAD software.
... These works can be divided into two categories. One is the FT methods for the conventional permanent magnet machines [5][6][7][8][9][10][11][12][13][14][15][16][17][18][19][20][21][22]. The other is some new topologies with good faulttolerance [23][24][25][26][27][28][29][30][31][32]. ...
... The winding configuration of machine which can be divided into overlapping and non-overlapping. Adopting the fractionalslot concentrated-winding [10] (FSCW, Fig. 5), electrical machine can satisfy the requirement of magnetic isolation. ...
... Yapılan tasarım da hava aralıgı degeri 1 mm olarak belirlenmiştir. Tasarımda performansı belirleyen bir diger kriter ise tel çapı ve sarım sayısının belirlenmesidir [27]. Denklem (8)'de tel çapının belirlenmesinde kullanılan ifadeye yer verilmektedir. ...
İnsansız kara araçları (İKA) sahip oldukları farklı modüller sebebiyle araştırmacılara çeşitli çalışma alanları sunmaktadır. Bu modüller sensör teknolojileri, gömülü sistemler, haritalandırma ve konumlama, yörünge takibi, mekanik tasarım, elektrik motoru ve batarya teknolojileri gibi alanlardan oluşabilmektedir. Bu araştırma alanlarından elektrik motoru teknolojisinde her ne kadar bahsedilen diğer alanlara göre daha fazla limit tasarım değerlerine ulaşılmış olsa da insansız araçların sahip oldukları karmaşık ve kendine özgü kısıtlar sebebiyle farklı tasarım yaklaşımlarına ihtiyaç duyulmaktadır. Yapılan çalışmada çok yönlü hareket kabiliyetli, düşük sürtünmeli ve yüksek titreşimli bir İKA için özel bir dış rotorlu fırçasız doğru akım motoru (FDAM) tasarlanmıştır. Yapılan tasarımda düşük hız, yüksek moment ve yüksek verimde bir FDAM’u kısıtlı alan ve hacim koşulları göz önünde bulundurularak kolay imal edilebilir bir yapıda geliştirilmiştir. Çalışmada analitik çözümler ANSYS RMxprt, 2 ve 3 boyutlu analizler ise sonlu elemanlar yöntemine (SEY) dayanan ANSYS Maxwell ile yapılmıştır. Elde edilen sonuçlar, başlangıç motivasyonu ile tasarım çıktıları arasındaki uygunluğu göstermiş ve üretilebilir bir elektrik motoru geliştirilmiştir.
