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An 8-pole 48-slot dual three-phase synchronous reluctance motor has been tested under half control mode, that is, when only a single three-phase system is supplied while the other is not operating. Changing the terminal connections of the motor prototype available, two different winding configurations have been tested. This allows their performances to be experimentally compared. At first, the cross coupling effect between the axis in $dq$ reference is analyzed, by measuring the flux linkages for different current combinations. The torque characteristics are compared in terms of torque map, maximum torque capability and torque ripple. Then the finite element analysis has been used to explain the experimental results and to investigate the radial forces on the rotor. Finally, the impact of a lack of symmetry between the two three-phase system is investigated. [ABSTRACT FROM AUTHOR]

This article proposes a novel dual three-phase flux-modulated switched reluctance motor (SRM) drive with maximum torque per ampere (MTPA) capability. Different from the existing open-winding structure, the stator winding is in dual three-phase connection, which effectively eliminates the side effects of the zero-sequence harmonic voltage component. Hence, the modulating region of the space vector pulsewidth modulation can be enhanced together with the increase of the dc-link voltage utilization ratio. The mathematical models of the dual three-phase flux-modulated SRM in the stationary reference frame and synchronous rotating reference frame are analyzed in detail. By considering the inductance nonlinearity, the MTPA control strategy is proposed based on the polynomial fitting method, which not only improves the torque capability but also simplifies the calculation of the current control system. The contributions of fundamental and harmonic currents to the electromagnetic torque are considered. By online adjusting the ratio of the dc-biased current component to the ac current component, the torque capacity can be improved. Besides, the effectiveness of the proposed MTPA control strategy can be enhanced by suppressing the harmonic current components caused by distorted back electromotive force. Experimental validations are provided to verify the effectiveness of the proposed SRM drive. [ABSTRACT FROM AUTHOR]

This two-part article compares the torque performance of 12 types of ac machines based on the same surface current density, tooth flux density, and rotor dimensions. Part II examines the torque capability of machines more recently developed which utilize the wave shaping capability of a solid-state frequency inverter. Essen's equation, as utilized in Part II, is modified to accommodate machines requiring non-sinusoidal waveforms. The “tau” factor, introduced in Part I, is also modified and is again used as means for comparison of any ac machine with an “ideal” machine based now upon a modified form of Essen's equation. [ABSTRACT FROM AUTHOR]

Integral-slot electrical machines require modifications and optimization of both stator and rotor to maximize the machine performance. In addition, sub-harmonics in magneto-motive force distributions is an important issue in motors with fractional-slot concentrated windings. These additional sub- and super-harmonics increase iron losses, which becomes an even bigger challenge in high speed/frequency applications. A permanent-magnet (PM) motor with unbalanced winding (UBW) and unconventional slot numbers is a good option for applications that require smooth torque output and low back electromotive force voltage harmonics. In this paper, different winding configurations and displacements of an unconventional nine-phase PM motor with both balanced fractional-slot winding and UBW structures have been investigated. The focus has been on 117-slot with 12-pole (for the balanced winding motor) and 36-pole (for the UBW motor) combinations. Motor prototypes with UBW configurations have been manufactured. The finite-element analyses results have been validated with experimental results and it is shown that such unconventional slot/pole combinations can be a good option for some high-power applications. [ABSTRACT FROM AUTHOR]

This paper proposes the novel scalable saturated model of synchronous permanent magnet machines, which combines ultrafast scaling laws with a saturated flux-linkage and loss model. The scalable model is used for the fast and accurate calculation of efficiency/loss maps and can also be used for drive cycle analysis including the calculation of energy consumption. It is verified by comparison with an existing state-of-the-art efficiency map and drive cycle analysis software. Additionally, an experimental verification of a saturated flux-linkage and loss model is presented. The additional possible usage of the scalable model is to find the optimal size of a scaled machine in order to meet the drive cycle performance and requirements of a traction motor. [ABSTRACT FROM AUTHOR]

In this paper, the influence of saturation and cross-coupling effects on the copper loss minimization for synchronous machines with strong saliencies, especially the permanent-magnet-assisted synchronous reluctance machines and reluctance synchronous machines are analyzed. It is shown that state-of-the-art methods for saturation consideration through the absolute inductances fail for these machines. A novel method for maximum torque per ampere estimation, which includes the consideration of these effects through the use of differential inductances, is proposed and its effectiveness is shown through finite-element analysis and experiments. [ABSTRACT FROM AUTHOR]

In this paper, an improved predictive torque control without weighting factor is proposed for a voltage source inverter-permanent magnet synchronous motor drive system, which possesses good control performance of torque and stator flux. By investigating the relationship among torque, the reference stator flux amplitude, and the phase angle of the stator flux, the reference stator flux vector is constructed. Then, the reference voltage vector is calculated by the reference stator flux vector based on the delay compensation and the deadbeat control. The extended control set is designed and two generalized base vectors that require further screening are determined based on the position of the reference voltage vector to improve the calculation efficiency. And the duty ratios used for the generalized base vectors are calculated, according to the geometric relations between the generalized base vectors and the reference voltage vector. Finally, by the duty cycle control between two generalized base vectors and between each generalized base vector and zero vector, the candidate vectors are gained and substituted into the cost function only with the flux vector error term. Experiment tests were carried out and the results validated the effectiveness of the proposed method. [ABSTRACT FROM AUTHOR]

This paper investigates the use of the Taguchi method for the design of line-start permanent magnet synchronous motors (LS-PMSMs). To address the inherent limitation of the Taguchi method in solving multiresponse optimization problems, an improved regression rate methodology and a weighted factor multiobjective technique are incorporated to form a Taguchi method based multiobjective design framework. To validate the proposed method, a prototype machine has been designed, constructed, and experimentally evaluated. It shows that the proposed method can effectively take into account both steady-state and transient synchronization performances in the design of LS-PMSMs. [ABSTRACT FROM AUTHOR]

Fractional slot concentrated winding (FSCW) interior permanent magnet (IPM) synchronous motors are nowadays an attractive solution in automotive applications due to their advantages in terms of high performance and manufacturing simplicity. Among the different topologies, the spoke type is an effective configuration when high torque density is required. On the other hand, the motor performance are heavily related to the selected slot-pole combination. This choice is critical in demanding automotive applications, such as electric power steering (EPS) systems, where high constraints in terms of torque density, torque quality, flux weakening performance, and noise/vibration/harshness are requested. This paper deals with the design and analysis of eight optimal slot/pole combinations FSCW IPM spoke type EPS motors. Two different low cost heavy rare earths free PM typologies, ferrite and hot-pressed NdFeB, are considered. A design and optimization procedure based upon the finite element analysis is presented. The impact of the magnetic properties and the slot/pole combination on the optimal motor dimensions, torque density, and motor cost is discussed. Cogging torque, torque ripple, electromechanical performance, and the stator deformation of the machines are evaluated, and the results are compared, highlighting the advantages and the differences among the solutions. [ABSTRACT FROM PUBLISHER]

It was recently demonstrated that the synchronous reluctance motor is well suited for electric as well as for hybrid electric vehicles. This paper deeply investigates the capabilities of a synchronous reluctance motor and compares them with those of a permanent-magnet-assisted synchronous reluctance motor, according to the typical requirement of a traction application. A proper rotor design is necessary. The average torque is due to the rotor anisotropy. The permeance difference between the direct- and the quadrature-axis is achieved by means of a high number of flux barriers. The position of the flux barrier ends and proper rotor asymmetries are chosen so as to reduce the torque ripple, mainly due to the slot harmonics. The impact of the rotor design on the motor performance is presented deeply, showing several simulation and experimental results, carried out on synchronous reluctance motors with different rotor geometries. Permanent magnets can be inset in the flux barriers to assist the synchronous reluctance motor improving its capabilities, but avoiding to use rare-earth permanent magnets. The main advantages of the permanent magnet assistance is an increase of the main torque density and of the power factor. They are evaluated experimentally. However, the drawback of adopting permanent magnets is the possible demagnetization of the magnets themselves. This can greatly limit the maximum overload capability of the motor, which is a salient requirement of a traction motor. [ABSTRACT FROM AUTHOR]

This paper presents an input–output feedback linearization (FL) control technique for rotating induction motors, which takes into consideration the magnetic saturation of the iron core. Starting from a new formulation of the dynamic model taking into consideration the magnetic saturation expressed in a space-state form in the rotor-flux-oriented reference frame, the corresponding FL technique has been developed. To this aim, a particular care has been given to the choice of nonlinear functions interpolating the magnetic parameters versus the rotor magnetizing current and the corresponding magnetic characteristic. The proposed FL technique has been tested experimentally on a suitably developed test setup and compared, under the same bandwidths of the speed and flux closed loops, with both the FL technique not taking into consideration the magnetic saturation and with the industrial standard in terms of high performance control of the induction motor: field-oriented control. A further comparison with the unique example present in the scientific literature of the FL control technique including the magnetic saturation has been shown, highlighting consistent improvements achievable by the proposed FL in terms of reduced computational demand and better dynamic performance. [ABSTRACT FROM AUTHOR]

This paper investigates the loss manipulation capabilities of deadbeat direct torque and flux control (DB-DTFC) induction machine drives. For each switching period, a volt-second-based inverse model provides a range of volt-second solutions to achieve the desired torque at the end of each switching interval, whereas the stator flux magnitude provides another degree of freedom to manipulate machine losses. With a flux-based DB-DTFC loss model proposed, losses can be manipulated each switching period without compromising torque dynamics. For a steady-state operation and typical process trajectories, the minimum loss can be achieved with corresponding energy savings. Alternatively, significant losses can be rapidly induced to dissipate kinetic energy in a machine during braking transients. This loss maximization technique provides significant braking torque without requiring additional hardware to transfer/dissipate energy. DB-DTFC induction machine drives provide an effective and elegant solution for continuous loss manipulation without compromising dynamic performance. [ABSTRACT FROM PUBLISHER]

In this paper, an investigation into an alternative topology for reluctance synchronous machine rotor flux barriers is presented. The investigated topology employs a high number of flux barrier variables with an alternative asymmetric rotor structure. The focus in this paper is on maximizing average torque and minimizing torque ripple, using finite element-based design optimization, in order to study the possibility of achieving acceptably low torque ripple. A subsequent investigation into the effect of rotor skew on the proposed optimized design to reduce torque ripple even further is also conducted, as well as the manufacturing and testing of the proposed flux barrier prototype. [ABSTRACT FROM PUBLISHER]

This paper addresses the causes of synchronous torques in split-phase induction motors. First, an analytical model is outlined to describe the processes involved in producing synchronous torques. This involves the consideration of the motor MMFs interacting with the slot permeances. The results from the implementation of the model are given for several different motor designs to calculate the synchronous torques. These highlight the way that the synchronous torque is a function of the MMF and slotting relationships. Measurement of the synchronous torque is not straightforward; however, a method of assessment is developed in this paper by using a deceleration test and other tests. The test results are fully described in this paper, and they illustrate that even with correct bar/slot combinations and skew, synchronous torques still exist in the machine. [ABSTRACT FROM AUTHOR]

This paper deals with the maximum torque and speed of permanent-magnet synchronous motor (PMSM) drives when the inverter output voltage is filtered by an LC filter with a cutoff frequency well below the switching frequency. According to steady-state analysis, the filter affects the performance of the motor drive, especially at high speeds. The stator current is not equal to the inverter current, and due to the inverter current and inverter voltage limits, the torque-maximizing stator current locus differs from that of a drive without the filter. A field-weakening method is proposed for PMSM drives with an inverter output filter. The method is implemented and tested in a 2.2-kW PMSM drive. The experimental results agree well with the analysis, and validate the high- speed performance of the proposed field-weakening method. [ABSTRACT FROM AUTHOR]

In recent years, much has been written about motors on variable-speed drives, high-speed rigid shaft motors, impact of API Standard 541, motor diagnostics, etc. Most of these papers and articles assume that the reader has significant knowledge of motor theory and operation. However, this assumption is overly optimistic, considering that only a few colleges teach motor theory today, and that application experience at motor user locations has been reduced in recent years. [ABSTRACT FROM AUTHOR]