Multiphase Winding Research Articles

Active Fault Current Mitigation With Multi-Phase Inverter and Windings for Resilience Against Short-Circuit Faults Between Adjacent Turns

Active Fault Current Mitigation With Multi-Phase Inverter and Windings for Resilience Against Short-Circuit Faults Between Adjacent Turns

Comparative Analysis of Noise and Vibration for Dual Three-Phase IPMSM Under Healthy and Multi-Phase Open-Circuit Fault Operations

The dual three-phase interior permanent magnet synchronous machines (IPMSMs) exhibit excellent fault-tolerant capabilities due to their multi-phase winding configurations. Under certain winding failure circumstances, by using the fault tolerant control (FTC) to reconstruct the normal rotating magnetomotive force, the machine can still provide the expected comparable torque as the healthy mode does. However, in the existing literature, limited attention was paid to the noise and vibration (NV) problems targeting the dual three-phase IPMSMs in FTC operation. To fill this knowledge gap, this paper conducts a quantitative comparison on the NV performance of a dual three-phase IPMSM under healthy and multi-phase open-circuit fault conditions under FTC. The comparative studies involve radial electromagnetic force, acceleration distribution, sound pressure level as well as machine housing deformation, which are analyzed under healthy and multi-phase open-circuit fault operations. Based on our exclusive findings, after applying the FTC, even though the machine can deliver the desired electromagnetic performance, the maximum deformation and sound pressure level of the IPMSM can be mitigated by 12.9% and 16.9%, respectively, compared to the ones under the faulty condition without FTC.

Performance Evaluation and Comparison of Three-Phase and Six-Phase Winding in Ultrahigh-Speed Machine for High-Power Application

This article investigates the influence of multiphase winding topologies in high-power ultra-high-speed machines (HP-UHSM) of 500 kr&#x002F;min. At this speed level, increasing the rotor&#x0027;s magnetic loading excites its critical bending resonances and leads to structural breakdown. On the other hand, increasing the stator&#x0027;s electric loading using the three-phase winding increases unwanted vibrations in a slotted stator and reduces the electromagnetic inter-action of the stator and rotor in a slotless stator. Consequently, the maximum output power level of UHSM (500 kr&#x002F;min or more) is limited to a few hundred watts only in the state-of-the-art. To over-come such a critical limitation, this article proposes a new design methodology for HP-UHSM, where the rotor&#x0027;s bending resonances and centrifugal stresses are restricted by limiting the maximum aspect ratio (<i>L&#x002F;D</i>), and an optimal multiphase winding is adopted in the slotless stator to increase the power level by effective electric loading. Also, a Multiphysics optimization is utilized to obtain the optimum magnetic loading and electric loading, where the bending resonance and other system limits are defined using multi-disciplinary design constraints. It is observed that the multiphase winding provides an added degree of freedom to increase the power level of UHSM without exciting the rotor&#x0027;s bending resonances and structural breakdown. Using the proposed method, a multiphase 2 kW 500 kr&#x002F;min HP-UHSM has been designed for the safety-critical AMEBA system and compared its Multiphysics performance with the three-phase machine having the same volume. Finally, exten-sive experiments are performed on both prototypes to validate the effectiveness of the proposed method. It is shown that the multi-phase HP-UHSM has no critical bending resonance below the 500 kr&#x002F;min, and it has 16.3&#x0025; higher output power with 1.18&#x0025; higher efficiency and 28.6&#x0025; lower back-EMF than the three-phase design.

Optimizing the Connection Diagram and Turns Number for the Three-Phase to Multiphase Transformer Converter Secondary Winding Coils

An approach to determining the optimal connection diagram and the number of turns for secondary winding coils of a three-phase to multiphase transformer-type converter is considered. Each phase of the device’s multiphase winding comprises three coils placed on different core limbs and connected in series with each other. To determine the connection diagram and the number of turns in the multiphase winding coils, it is necessary to solve an optimization problem with taking into account certain constraints that will make it possible to obtain the same number of turns in the series-connected coils of each secondary winding phase, a symmetrical multiphase EMF system, and uniformly distributed symmetrical multiphase load among the three primary winding phases. The formulated optimization problem with constraints is solved using the numerical interior point method. The application of the proposed approach is illustrated by an example of calculating the minimum number of turns in the coils of a three-phase to seven-phase converter, and the converter windings connection diagram is presented. The article gives the calculated apparent power values of the secondary winding coils with a symmetrical resistive-inductive load for a converter with different numbers of coil turns evaluated from solving the optimization problem with various constraints. A prototype three-phase to seven-phase converter has been fabricated on the basis of a three-phase transformer of a standard series. As a result of experimental studies of the prototype, the seven-phase winding instantaneous voltage waveforms, r.m.s. values of currents and voltages, and the primary winding power for no-load and symmetrical load modes have been obtained. The experimental study results have confirmed the calculation results adequacy. By using the proposed approach, it is possible to design a three-phase to multiphase converter with the number of multiphase secondary winding phases more than two. The designed secondary winding coils will have the minimal number of turns, which will make it possible to manufacture a device with smaller mass and dimension indicators and decrease the consumption of expensive electrical materials.

Resulting Vectors of Multiphase Winding Discrete Voltage States

Resulting Vectors of Multiphase Winding Discrete Voltage States

Design and Analysis of Dual Stator PMSM With Separately Controlled Dual Three-Phase Winding for eVTOL Propulsion

The propulsion system of the electric-powered vertical take-off and landing aircraft requires a high level of performances, including power density, efficiency, noise vibration and harshness, and fault tolerance. Among many types of conventional electric motor, the outer rotor surface-mounted permanent magnet synchronous motor (SPMSM) is widely used for its high power density and low torque pulsation. However, these advantages are degraded when the multiphase winding is applied to secure the fault-tolerance characteristics. To overcome the limit of conventional motor topology, the dual stator permanent magnet synchronous motor with separately controlled dual three-phase winding is proposed. The advantages of the proposed topology are resulted from the feature of mechanical, electrical, and magnetic isolation. To maximize the distinctive feature, a design process considering separated current vector control (SCVC) method is established. A design example is presented to demonstrate the impacts of the proposed design process considering SCVC on the power density maximization, torque harmonic reduction, and efficiency improvement. Finally, the experimental verification is presented to validate the proposed design and control techniques.

Low-Complexity Model-Predictive Control for a Nine-Phase Open-End Winding PMSM With Dead-Time Compensation

The heavy computational burden and the complexity in pulse generation based on multivector synthesis represent serious challenges for applying finite control set model-predictive control (FCS-MPC) in multiphase open-end winding (OW) drive systems. In this article, a low-complexity model-predictive control with dead-time compensation is proposed for the nine-phase OW permanent magnet synchronous machine drive system. First, to simultaneously eliminate voltage vectors on the third, fifth, and seventh harmonic planes, three vectors in the same direction are selected to synthesize the virtual vector (VV). In addition, a multivector synthesis algorithm is designed to generate a symmetrical pulse sequence. Then, in order to suppress the harmonic voltage vector caused by the dead time, an additional voltage vector was added to the VV. Finally, the deadbeat principle was introduced to calculate the reference voltage vector, and the optimal voltage vector is determined according to the position of the reference voltage vector, which reduces the computational burden successfully. The proposed method is studied and compared with traditional FCS-MPC schemes. Simulation and experimental results have verified the effectiveness of the proposed method, which reduces the computational burden and complexity and enables the use of FCS-MPC for multiphase OW drive systems.

Technical Review of Traction Drive Systems for Light Railways

Due to environmental concerns, governments around the world are taking measures to decarbonise railway transport by replacing diesel traction systems with cleaner alternatives. While the electrification of railway systems is spreading rapidly, it is unlikely that all routes will be electrified as the volume of passengers will not justify the high infrastructure costs. Therefore, it is expected that, for several lines, a combination of hydrogen and electric traction will be used, with the latter partly provided by fixed infrastructure and partly by batteries. Railway traction drives will then need to change to accommodate these new types of power supply. A detailed review of the available traction motors and drives is provided with this review, given application to the new hybrid-electric systems. In particular, permanent magnet synchronous motors with multiphase windings are evaluated in comparison with traditional three-phase machines. Additionally, low and medium-voltage multisource power converters have been reviewed, taking into account the introduction of wide band-gap semiconductor devices.

Analysis of winding MMF of PMSM with multi-phase and multi-layer layout using holospectrum method

A holographic spectrum method (HSM) of multi-phase and multi-layer winding magnetomotive force (MMF) for 12-slot/10-pole combination with fractional-slot concentrated-winding (FSCW) is proposed in this paper. Taking two kinds of traditional winding layout as example, amplitude and phase distribution of the vth harmonic are calculated. The holospectrum of the multi-phase and multi-layer winding are derived based on three-phase single-layer (TP-SL) and three-phase double-layer (TP-DL) holospectrum theory. Then the finite element method (FEM) is used to validate the resultant winding MMF calculated by the holospectrum method. Results show that two methods have a good consistency in changing tendency. Prototype manufacture and test of axial-flux PMSM with a double-three-phase four-layer (DTP-FL) winding have been completed. A load experiment with two groups of resistance is established to validate its output power of axial-flux permanent magnet synchronous machine (PMSM). The temperature distribution of axial-flux PMSM is evaluated with PT100 and infrared thermal imager. The experiments shows that the axial-flux PMSM runs at a relative temperature rise.

Performance Analysis of a Rewound Multiphase Synchronous Reluctance Machine

This article analyses the performance of synchronous reluctance motors (SynRMs) when an existing three-phase stator is rewound (REW) to a higher number of phases. The introduced rewinding technique offers an optimized distribution for air-gap flux, higher winding factor, and higher value for the fundamental component of the magnetomotive force with lower harmonics. The number of turns of the proposed multiphase winding is calculated, keeping fixed copper volume. Finite element simulations verified that the torque density of the REW five- and seven-phase SynRMs is enhanced by 6.56% and 3.37%, respectively, over the existing machine under rated conditions. The torque ripple is also reduced by 17.13% and 15.87%, respectively. Furthermore, the efficiency is enhanced with the REW machines by 0.3% at rated condition. Moreover, the torque gain is greatly increased to 23.48% at higher speed (9000 rpm) and the efficiency is also increased by 3%. The main advantage of the REW machine is clearly observed in case of an open-circuit fault. With one-phase opened, the REW machine can work at 78% of the healthy rated torque, while the three-phase machine works at only 43% with a very huge torque ripple about 228%. Experimental measurements are obtained to validate the theoretical work.

Multiphase Stator Winding: New Perspectives, Advanced Topologies, and Futuristic Applications

Multiphase winding configurations have gained significant attention in high-performance variable speed drives and wind energy conversion systems (WECS) owing to their myriad advantages. In the available literature, various multiphase winding layouts have been designed aiming at boosting the machine performance to meet the requirements of the proposed applications. Ultimately, this paper surveyed the state-of-the-art in the available multiphase winding layouts proposed for various innovative applications. Various types of windings were discussed, while investigating their advantages and limitations. This typically considers the winding layouts employed in multiphase induction motors (IMs) and permanent magnet (PM) machines with prime phase and multiple three-phase orders. This study extensively provides innovative winding arrangements that offer better machine characteristics in terms of torque density, efficiency, and fault-tolerance capability. Moreover, the construction of multiphase machines with general <italic xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">n</i> -phase using standard three-phase stator frames has been elaborated. This latter technique obviates the basic necessity of special stator frames with a prime number of phases. Finally, this paper sheds light on the commercial applications that include multiphase winding layouts.

Определение минимального числа витков катушек вторичной обмотки трансформаторного трехфазно-многофазного преобразователя числа фаз

The article has considered an approach to determining the minimum of the secondary winding coils turns of a transformer three-phase-multiphase phase number converter. Each phase of the secondary winding of the considered converter consists of three coils connected in series placed on three different rods of the magnetic circuit. In order to solve the optimization problem, the interior-point method is used. As an example, for a three-phase-five-phase converter has determined the minimum number of turns of the secondary winding, the total power consumed by the coils of the secondary winding is calculated. A vector diagram EMF of the coils of the secondary winding is constructed, explaining the formation of a symmetrical five-phase EMF system at the terminals of the secondary winding. Using the proposed approach, it is possible to design a transformer converter of the number of phases with a three-phase primary winding and a multiphase secondary winding, the number of phases of which is more than two.

МОДЕЛИРОВАНИЕ РАБОТЫ ТРЕХФАЗНО-МНОГОФАЗНОГО ТРАНСФОРМАТОРНОГО ПРЕОБРАЗОВАТЕЛЯ ЧИСЛА ФАЗ С ЛИНЕЙНОЙ СИММЕТРИЧНОЙ НАГРУЗКОЙ

Currently, various phases number converters are used in practice, which are necessary for the operation of rectifiers, inverters, multiphase electric machines and power transmission lines. Increasing phase numbers in most cases makes it possible to improve the energy, weight and size and other performance indica-tors of such converters and systems. The article lists phase number converters with different operating principles. A three-phase-multiphase transformer converter of the number of phases is considered in more detail, in which each phase of the multiphase secondary winding consists in general of three series-connected coils placed on each of the three rods of the transformer core. The work of a three-phase-five-phase transformer converter with a linear symmetric active-inductive load is analyzed. As a result of the calculation, the EMF, currents and total power of the coils of the secondary five-phase winding are determined. The total power of the coils of the secondary winding placed on one limb of the transformer core is equal to the power of the coils located on each of the other two limbs which allows for uniform power distribution of the multiphase load across the three phases of the primary winding.

Comparison of Combined Winding Strategies for Radial Nonsalient Bearingless Machines

This paper investigates and compares two popular combined winding configurations for bearingless machines, the multi-phase (MP) and dual-purpose no-voltage (DPNV) windings. Each of these winding configurations has the ability to independently create suspension force and drive torque using the same stator coils. The paper develops analogous bearingless motor force and torque models, space vector equivalent circuits, and a current regulation architecture for each combined winding approach. A comprehensive comparison is made between the two combined winding topologies by using these analogous models and through an experimental study. It is shown that, from a motor design perspective, these combined winding topologies are equivalent for certain design conditions, but that each winding places very different demands upon the drive power electronics. The paper concludes that the optimal choice of winding configuration depends on the machine parameters and the expected loading and drive cycle. When compared in terms of total current stress exerted on the bearingless drive, the MP winding is preferred when over half of the coil current is used to produce torque rather than force. In terms of the drive's volt-ampere rating, the DPNV winding is shown to be advantageous for high operating speeds and low torque values.

Analysis of features of magnetic field of a synchronous electric machine with a multi-phase fractional slot winding in a polyharmonic mode of operation

An analytical model has been developed for calculating magnetic field in a multiphase synchronous electric machine with fractional toothed windings. For this, a harmonic analysis of the distribution functions of the magnetic field of excitation and the magnetic field of the armature reaction was carried out, taking into account the presence of higher harmonic components in the function of the magnetomotive force of permanent magnets, variable magnetic conductivity of the air gap, polyharmonic mode of operation of a multiphase electric machine and a non-sinusoidal law of variation of spatial winding functions. As a result of the analysis, the substantiation is given that in the investigated electric machine a nine-phase winding can extract with the greatest efficiency the harmonic components of the first and third order of a rotating magnetic field to create flux linkage and induce an electromotive force (as well as create a magnetomotive force with prevailing spatial harmonics of the first and third order). In the investigated electric machine, the amplitudes of the working harmonics of the induction of the modulated magnetic field of the armature reaction can be increased due to the modulation of the inoperative harmonics of the magnetomotive force of the armature response by the stator teeth to the first and third order. To check the developed provisions, a magnetostatic vector model of the magnetic field of the investigated electric machine was created. The simulation results confirmed the high efficiency of the developed analytical model for calculating the magnetic field in a synchronous electric machine with fractional toothed windings. The use of such a model will make it possible to reveal most reliably the influence of the geometricparameters of the magnetic circuit and the multiphase winding circuit on the nature of the change in the functions of the magnetic field in the air gap with the lowest time costs in the process of optimizing an electric machine.

Analytical analysis and performance characterization of brushless doubly fed induction machines based on general air-gap field modulation theory

Air-gap magnetic field modulation has been widely observed in electric machines. In this study, we present an analytical analysis and performance characterization of brushless doubly fed induction machines (BDFIMs) fed by two independent converters from the perspective of air-gap field modulation. The spiral-loop winding is studied in detail as an example to show the generalized workflow that can also be used to analyze other short-circuited rotor winding types, such as nested-loop and multiphase double-layer windings. Magnetic field conversion factors are introduced to characterize the modulation behavior of special rotor windings and facilitate their comparison in terms of cross-coupling capability, average torque, and harmonic content of the air-gap flux density waveforms. The stator magnetomotive force (MMF), rotor MMF, and resultant air-gap MMF are considered, based on which the closed-form inductance formulas are derived, and the torque equation is obtained along with the optimal current angle for maximum torque operation by using the virtual work principle. The design equations are then developed for the initial sizing and geometry scaling of the BDFIMs. Transient finite element analysis and experimental measurements are performed to validate the analysis.

Winding MMF and PM MMF Analysis of Axial-Flux Machine with Multi-Phase and Multi-Layer Winding

According to star graph and winding distribution, winding MMFs of three kinds of 12-slot/10-pole multi-phase and multi-layer winding layout are analyzed by the improved winding function method. Analysis results show that multi-phase and multi-layer winding can suppress even order and (12n ± 1) order harmonics, thereby reducing the eddy-current loss in PMs. Based on the unfolded LPMSM model, rotor MMF, air gap flux density, and no-load back-EMF are analyzed by the analytical permeance function method, which is validated by Teslameter and no-load experiment. Winding MMF is validated by FEM. An axial-flux integrated starting/generator (ISG) with double-three-phase four-layer (DTP-FL) winding, segmented armature and PM, and centrifugal fan is designed and manufactured. The no-load and load test with two groups of resistance established has validated the reasonability of the mentioned method. Experiments show that the axial-flux ISG prototype can run at a relative temperature rise.

Пульсация потенциала общей точки трехфазной и пятифазной обмоток двигателя относительно «нуля» преобразователя

The aim of the study is to determine the parameters characterizing the ripple of a motor's three- and five-phase windings common point potentials (for the star winding connection diagram) with respect to the converter zero point. One of the reserves for decreasing electromagnetically induced vibration of an electric motor with a rotating field is to increase the number of working winding phases. The study subject is a five-phase motor winding connected to a bridge converter, namely, its ability to reduce electromagnetically induced vibration in comparison with that in using a three-phase winding. The common point potential ripple parameters are studied, and an approach is proposed to estimating the amplitude modulation of the space-time voltage vector of three- and five-phase windings under the influence of the common point potential ripple with respect to the converter zero point. Theoretical studies were carried out using the Fourier series expansion method and vector analysis methods. To confirm the theoretical results, experimental studies of the prototypes of three-phase and five-phase synchronous motors with inductors made on the basis of permanent magnets were carried out. The main results have shown the following. With increasing the number of phases of the rotating field motor working winding connected to a bridge converter, the common point potential ripple amplitude with respect to the converter zero point decreases, and the ripple frequency increases. The product of ripple amplitude by frequency remains unchanged. It is assumed that the common point potential ripple of the motor multiphase winding with respect to the converter zero terminal results in the amplitude modulation of the space-time voltage vector. With increasing the number of winding phases, the modulation amplitude decreases, and the modulation frequency increases. A five-phase motor has a lower level of the working winding common point potential ripple with respect to the converter zero point in comparison with a three-phase motor. Thus, it can be assumed that there will be a lower level of electromagnetically induced vibration in using a simple converter operation algorithm. The obtained results can be used in designing electric traction systems with vector control on the basis of multiphase motors. With increasing the number of phases, the common point potential ripple amplitude in a multiphase winding with respect to the converter zero point decreases, and the ripple frequency increases. Thus, the common point potential ripple amplitude in a five-phase winding is 5/3 times less than that in a three-phase winding, and the ripple frequency increases by 5/3 times, respectively. With increasing the number of working winding phases, the amplitude modulation of the resulting space-time voltage vector decreases. This circumstance has a positive effect on decreasing the electromagnetically induced vibration.

A General Investigation on the Differential Leakage Factor for Symmetrical and Asymmetrical Multiphase Winding Design

This work provides an investigation based on a fast estimation of the degree of unbalance (D.U.%) and the differential leakage factor (σ0) of multiphase electrical machine windings. This analysis is carried out by exploring almost 5000 combinations in terms of number of slots, pole pairs, phases and layers. The variability of the leakage factor is examined for each condition, defining an optimal region for its minimization. As a result, an extended mapping is carried out for both the degree of unbalance and the leakage factor, providing a useful tool during the early design stage of winding configurations for multiphase electric machines, even with slight asymmetries. The results obtained from this investigation are validated through finite element analysis and demonstrate that the differential leakage factor can be significantly reduced by adopting winding configurations with slight asymmetries, which also represent a valuable alternative in the electrical machine design.

Design, Analysis and Validation of a Six-Phase Induction Machine from a Commercial Three-Phase for Academic Research

Multiphase machines have been reemerged for high-power as well as fault-tolerant applications such as electric vehicles and wind turbines. Nevertheless, these types of machines are typically built only for industries for specific purposes. Therefore, the availability of multiphase machines in the market for academic research work, for instance at universities, is limited due to they require special construction processes and involve high initial costs for the companies. For that reason, the aim of this paper is to present a step-by-step design of a multiphase winding of an induction machine (IM) from a commercial three-phase IM for academic research use. The obtained results will be first analyzed by using the ANSYS Maxwell simulation environment. Then, a model-based current controller will be performed to validate the proposed design and the electric parameters of the six-phase IM.