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A detailed analysis has been conducted on two motor control algorithms: direct torque control (DTC) and field-oriented control (FOC). There are two ways that a voltage source inverter (VSI) can regulate a permanent magnet synchronous motor (PMSM). When using the PMSM and voltage source inverter (VSI), dead time is employed to turn off both the upper and lower switches to prevent short circuits. However, by supplying the PMSM with unexpected polarity voltages at the VSI output voltage, this switching technique reduces distortion. It is challenging to utilize the sensor to directly detect the fault voltage that results in an open circuit. This work examines the nonlinearity of the electric power controller during dead time during PMSM operation using the DTC algorithm to increase control stability. The stress distribution is estimated using an extended Kalman filter (EKF). Ultimately, the model presented in this study verified the increase in stator current and torque output through simulations and testing. [ABSTRACT FROM AUTHOR]

Purpose – Switching power converters for photovoltaic (PV) applications with high gain are rapidly expanding. To obtain better voltage gain, low switch stress, low ripple and cost-effective converters, researchers are developing several topologies. Design/methodology/approach – It was decided to use the particle swarm optimization approach for this system in order to compute the precise PI controller gain parameters under steady state and dynamic changing circumstances. A high-gain q- ZS boost converter is used as an intermittent converter between a PV and brushless direct current (BLDC) motor to attain maximum power point tracking, which also reduces the torque ripples. A MATLAB/Simulink environment has been used to build and test the positive output quadratic boost high gain converters (PQBHGC)-1, PQBHGC-8, PQBHGC-4 and PQBHGC-3 topologies to analyse their effectiveness in PV-driven BLDC motor applications. The simulation results show that the PQBHGC-3 topology is effective in comparison with other HG cell DC–DC converters in terms of efficiency, reduced ripples, etc. which is most suitable for PV-driven BLDC applications. Findings – The simulation results have showed that the PQBHGC-3 gives better performance with minimum voltage ripple of 2V and current ripple of 0.4A which eventually reduces the ripples in the torque in a BLDC motor. Also, the efficiency for the suggested PQBHGC-3 for PV-based BLDC applications is the best with 99%. Originality/value – This study is the first of its kind comparing the different topologies of PQBHGC-1, PQBHGC-8, PQBHGC-4 and PQBHGC-3 topologies to analyse their effectiveness in PV-driven BLDC motor applications. This study suggests that the PQBHGC-3 topology is most suitable in PV-driven BLDC applications.

In this paper, a novel method to design and optimization of a 1.5 kW, 4-pole, 36-slot salient-pole permanent magnet synchronous machine (SPPMSM) based on a three-step skewed pole shoe method to reduce the output torque ripple and the cogging torque is investigated. In the first step, an initial model of the SPPMSM is designed, simulated, and verified through the Finite-Element method (FEM). The simulation results ensure the electromagnetic performance of the initial model of the machine under any operating conditions. Next, a novel method to re-design and optimize the SPPMSM based on a three-step skewed pole shoe shape is presented.. The significant results obtained from the optimized model of the SPPMSM are as: The output average torque and the air gap flux density are increased approximately by 12.65% and 3.33%, respectively compared to the initial design of the SPPMSM. The torque ripple is an important parameter in the design of the machine, and so, is decreased by about 16.03% which is equal to 10.41% in comparison with the initial model which is equal to 12.41%. The cogging torque in the initial model of the SPPMSM is equal to 0.036 N.m and with a 19.44% reduction, in the optimized model, it is 0.029 N.m. And finally, the back-EMF voltage of the SPPMSM is improved by 1.27% compared to the initial design model. [ABSTRACT FROM AUTHOR]

Smart, Micro and Nano-grids are the future of electric power systems. In parallel with this future, electric vehicles (EVs) take a great deal of attention, as they are one of the important elements in these systems. Also, with the passage of time, the development continues in the technology of manufacturing EVs. Since the electric motor is the main component in these vehicles, research and development is continuing to find the most suitable motors that can work in such vehicles. The synchronous reluctance motor (SynRM) is the newest motor used in this industry. SynRMs faces different challenges, one of which is the torque ripples. Different trials were used to reduce or eliminate or minimize these ripples. Most of previous work focuses on the SynRM design parameters to reduce torque ripples. In this paper, the control methodology and the strong action controller (SAC) are used as a tool to reduce these ripples. The simulation results showed the effectiveness of the application of the proposed SAC in ripples factor reduction. This reduction represents a new contribution over the already existed techniques.

A novel approach to the design of power factor correction (PFC) and torque ripple minimization in a brushless direct current (BLDC) motor drive with a new pulse width modulation (PWM) technique is demonstrated. The drive was designed to have a better power factor (PF) and less torque ripple. On the other hand, the modified Zeta converter is used to enhance the power factor of the proposed system. The modified Zeta converter is operated in discontinuous inductor current mode (DICM) by using a voltage follower technique, which only needs a voltage sensor for power factor correction (PFC) operation and DC-link voltage control. The output voltage of the VSI is determined by switching patterns generated by the PWM-ON-PWM switching strategy, and it reduces the torque ripples. The proposed drive is developed and simulated in a MATLAB/Simulink environment. The power factor of 0.9999 is produced by the PFC modified zeta converter topology and the PWM-ON-PWM scheme reduce the torque ripple in the commutation region by 34.2% as compared with the PWM-ON scheme. This demonstrates the effectiveness of the suggested control method. [ABSTRACT FROM AUTHOR]

The performance enhancement of the Induction Motor (IM) is a crucial and strenuous task. The Direct Torque Control (DTC) method is a common control strategy for boosting the IM drives and wildly implemented due to its merits including insensibility to motor parameters and fast response. However, the main shortage of the traditional DTC method is that it may lead to large flux and torque ripples. In this regard, this paper proposes an efficient control method called a Finite-State Predictive Torque Control (FS-PTC) which is based on multi objective optimization technique to overcome the shortage in the conventional DTC method. In addition to that a ranking approach is presented to assign the weighting factor in the cost function which directly affects the performance of system. The proposed ranking approach is based on elimination the weighting factor by replacing the single cost function with two different cost functions. The proposed FS-PTC is applied and tested using the dSPACE environment to validate its effectiveness and efficacy. From the experimental simulations, the performance of system is enhanced considerably where the torque and flux ripples are reduced with maintaining a constant switching frequency compared to the conventional DTC.

This article introduces a new technique for reducing the time of calculating radial and tangential force density waves of switched reluctance machines (SRMs). The method is based on the finite element (FE) simulation of a fraction of an electrical cycle. The new approach shows that a significant time reduction is achieved as compared to the time required for stator radial force density and the rotor tangential force calculation based on the one mechanical cycle simulation method. As the switched reluctance motors introduce new challenges in aspects such as acoustic noise, vibrations, and torque ripples, the method introduced in this paper will help reduce the time of the optimization process of switched reluctance machines in the design stage to improve the machine performance. The proposed method is applied to radial flux SRMs. Three different topologies were used to show the effectiveness of this technique in different force components with minimal error as compared to the benchmark method based on the FE simulation of one mechanical cycle.

Switched reluctance motor (SRM) drive has outstanding features like robust construction, double saliency, fault tolerance capability, and heat withstanding capability. Despite these, torque ripple is an intrinsic characteristic of SRM because of double salient geometry, air gap length, and switching sequence of motor phase currents, making it unsuitable for slick torque and high dynamic performances applications. This paper discusses the novel Torque Sharing Function (TSF) implementation and the flower pollination algorithm-based intelligent controller to minimize the torque ripples in Switched Reluctance Motor (SRM). TSF values depend on commutation angles during turn on, turn off, and overlapping angles. The proposed TSF and flower pollination algorithm evaluates the performance parameters using the machine model and controls the torque ripples for a wide range of speeds. Additionally, optimal results are obtained using three TSFs functions with valuable guidance provided for TSF selection. The proposed TSF with flower pollination algorithm-based intelligent controller finds its suitability for online evaluation of optimal turn on, turn off, and overlapping angles. The performance of the proposed method has effectively reduced the torque ripple in SRM than the Differential Evolution (DE) algorithm. [ABSTRACT FROM AUTHOR]

Copyright of Przegląd Elektrotechniczny is the property of Przeglad Elektrotechniczny and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

The direct torque control (DTC) of permanent magnet synchronous motor (PMSM), which includes flux and torque double closed-loops, requires constant flux and high calculation accuracy. Besides, uncertain flux estimation will cause torque ripples. To solve these problems, in this paper, twelve-sector direct torque control (DTC) without flux closed-loop for PMSM is proposed. To reduce the requirement on constant flux and high calculation accuracy and to simplify the structure of the system, the flux closed-loop is removed from the control system. To suppress the torque ripple, a twelve-sector space voltage vector control scheme is adopted which increases the switch states of the inverter. The number of nonzero voltage vectors is increased from 6 to 12 without increasing the hardware equipment of the system. The sections of the voltage vectors are redefined and the torque ripples are reduced. The hardware-in-the-loop simulation results show the effectiveness and feasibility of the proposed method. [ABSTRACT FROM AUTHOR]

Electrical machines having more than one independent three-phase unit are mostly proposed for applications that require the machine to operate continuously, even under one or more three-phase units fault. This paper discusses the concept of multi three-phase unit motor machine design in which the machine stator is divided into multiple three-phase units, with three stator slots and a rotor pole pair constituting a single independent three-phase unit motor. Firstly, an analytical method is presented to calculate the magnetomotive force (MMF), its harmonic spectrum and their impact on the machine torque ripples for the multi three-phase unit motor machine model. The proposed algorithm can be used to study the MMF and torque ripples behaviour of any multi three-phase unit motor machine operating under healthy and open-circuit fault operation. Moreover, different multi three-phase winding configurations including multi three-phase concentrated, multi three-phase distributed and multi three-phase mixed concentrated and distributed winding configuration are investigated for the modular type machine prototype. The analyzed multi three-phase winding configurations are fully studied to investigate the MMF harmonic components, the generated torque and torque ripples under healthy and open-circuit fault operations. The performance analysis of the prototype machine is investigated using detailed Finite Element Analysis (FEA) under the analyzed multi three-phase winding configurations, validating the effectiveness of the proposed multi three-phase unit motor machine windings configurations. This study presents useful conceptual hints for the multi three-phase unit motor machine design, while the analyzed three different types of winding configurations can help machine designers select the best multi three-phase winding design approach with lower generated torque ripples and lower unbalanced magnetic forces, particularly under different unit motors open-circuit fault operating conditions.

A novel flux-intensifying interior (FII) permanent magnet synchronous motor (PMSM) based on multilayer barriers in rotor structure with improved torque performance for solar water pump system is proposed here. The conventional interior (CI) PMSM generates maximum total torque on application of negative current along d-axis, resulting in an increment of demagnetization possibility of permanent magnets (PMs). Although flux-intensifying PMSMs solve this issue, their reluctance torque is lower due to the reduced saliency difference. This problem is solved by the presented FII-PMSM, which produces higher reluctance torque through specially designed barriers. Two types of barriers namely, inner and outer cutoff barriers are designed in rotor along quadrature axis. The inner barriers realize flux-intensifying effect while the outer cutoff barriers increase the saliency difference and hence the reluctance torque. Besides, the dimensions of barriers are optimized by using parametric optimization to maximize saliency difference and minimize torque ripples. The finite element methods based electromagnetic performances of FII-PMSM like inductance curves, torque profiles, airgap gap flux density, back electromotive force plots, efficiency map, output power map and PM flux density are obtained and compared with the CI-PMSM to show the superiority of presented motor.

The delivery of combined benefits of Alternating Current (AC) motor and Direct Current (DC) Motor makes the Brushless Direct Current (BLDC) motors as a unique feature in numerous industrial applications. The possibilities of running the motor at very high speed with extensive operating life span of BLDC with miniature and its compact design make it an un-ignorable option for Electrical Engineers. With many advantages, till managing as well as controlling the speed of BLDC is complicated. This work is intended to come up with an effective control of speed of the motor through Torque Ripple Minimization Route and an Enhanced-Fractional Order Proportional Integral and Derivative Controller based Ant-Lion Optimizer (EFCA)Technique, which is evaluated as well as its strategy is executed in this paper. The critical factors like BLDC's Back Electro Magnetic Force, Values of Current, Torque level and the operating speed of the motor are considered and evaluated closely and from that, the ripple level present in the torque is controlled as well as it is brought down to minimalistic value by using Fractional Order (FO) Proportional Integral Derivative (FOPID) controller. To control the speed of the motor, the Gain parameters and the ripple present in the torque have to be reduced, the latter is obtained using FOPID controller and the former is achieved by employing Modified - Ant Lion Optimizer (ALO). The technique presented in this paper helps for the enhancement of controlling behavior of BLDC and improves the overall performance of the motor. The dynamic part of the BLDC is analyzed using the platform of Matrix Laboratory (MATLAB) simulink and the results are tabulated. The final values are compared with the results of the existing methodologies and the comparative study has yielded that the presented technique has outperformed than that of the available methodologies. A proto type model has been designed and results are executed in real time environment to ensure the effectiveness of the presented work. [ABSTRACT FROM AUTHOR]

Recently, in various industrial fields, including automated manufacturing processes, industrial robots are becoming indispensable equipment; these robots perform repetitive tasks and increase the productivity of the production line with consistent precision and accuracy. Thus, fault diagnostics of industrial robots is an essential strategy to prevent the significant economic losses that can be caused by a sudden stop of a production line due to an industrial robot fault However, previous data-driven industrial robot fault diagnostics are limited because a pre-trained model built for a specific motion may not accurately or consistently detect faults in other motions, due to motion discrepancies. To overcome this difficulty, in this paper, we propose a deep transferable motion-adaptive fault detection method that uses torque ripples for fault detection of industrial robot gearboxes. The proposed method is composed of two stages: (1) a residual–convolutional neural network is used to enhance the performance of feature extraction for simple motions, after first refining raw torque signals by filtering out the motion-dependent signals (2) a binary-supervised domain adaptation is performed to detect faults adaptively on multi-axial motions through adversarial contrastive learning. The efficacy of the proposed method was validated using experimental data from unit-axis and multi-axial welding motions collected from a real industrial robot testbed. The proposed method showed superior fault detection accuracy for the motion adaptation task, as compared to existing methods. • A novel, deep, transferable, motion-adaptive fault detection method for industrial robot gearboxes is proposed. • Motion-invariant fault-related features of torque ripples are learned. • Experimental validations are provided, examining two real industrial welding motions. • The proposed method showed superior fault detection performance, as compared to earlier methods. [ABSTRACT FROM AUTHOR]

This paper presents performance improvement of dual stator axial-flux spoke type permanent magnet vernier machine (DSAFST-PMVM), which has the capability to generate high torque at a lower speed due to magnetic gearing effect. Flux focusing effect is created by means of dual stator single rotor topology with spoke type permanent magnets. It is best suitable for high-performance industrial applications such as servo motors, robot arms, wind power, electric vehicles, and elevator applications. A PM shape is proposed in this paper which has notches in such a way that it produces discrete skew effect which reduces the cogging torque and torque ripples. Optimization of magnet shape is done to make the optimized model more competitive than the proposed and basic models. Main parameters such as back emf, cogging torque, torque ripples, electromagnetic torque, VTHD, airgap flux densities, flux density distribution, power factor, and power of the machine are compared among the basic model, proposed model, and optimized models. The comparative analysis is done by using the time stepped 3D finite element method.

The aim of this paper is to design, analyze and optimize the “Multi-Stack Slotless Axial Flux Switching Permanent Magnet Machine”. In the design process, mathematical models are implemented, and the Finite Element Method (FEM) is performed to analyze the machine performances. The paper aims to minimize the occurrence of cogging torque and torque ripple in the multi-stack slotless stator AFPM machine. As a consequence, it reduces the vibrations in the machine and increases its life span. Multi-stack slotless stator AFPM machine with a right-angled trapezoid-shaped PM is proposed and comparison is done with conventional shape AFPM machine. In order to examine the performance of multi-stack slotless stator AFPM machine Finite Element Analysis (FEA) is used. To further enhance the characteristics of the designed machine with the proposed right-angled PM shape, optimization is done by considering inner and outer pole pitch as the design variables. In optimization process, krigging method assigned with Latin Hyper-cube Sampling and a genetic algorithm (GA) is performed due to suitability with non-linear data. Then, finite element analysis by JMAG-Designer is performed to verify the results. It is determined that optimized model has achieved 65% reduction in torque ripples as compared with the conventional design. Hence, this work attempts to optimize the performance of the AFPM machine.

The main aim of this paper is to present a novel control approach of an induction machine (IM) using an improved space vector modulation based direct torque control (SVM-DTC) on the basis of imaginary swapping instant technique. The improved control strategy is presented to surmount the drawbacks of the classical direct torque control (DTC) and to enhance the dynamic performance of the induction motor. This method requires neither angle identification nor sector determination; the imaginary swapping instant vector is used to fix the effective period in which the power is transferred to the IM. Both the classical DTC method and the suggested adaptive DTC techniques have been carried out in MATLAB/SimulinkTM. Simulation results shows the effectiveness of the enhanced control strategy and demonstrate that torque and flux ripples are massively diminished compared to the conventional DTC (CDTC) which gives a better performance. Finally, the system will also be tested for its robustness against variations in the IM parameters. [ABSTRACT FROM AUTHOR]

Unique double salient structure of Permanent Magnet Flux Switching Machines (PMFSM) with both Concentrated Armature Winding (CAW) and Permanent Magnet (PM) on stator attract researcher's interest for high speed brushless application when high torque density (T den ) and power density (P den ) are the primal requirements. However, despite of stator leakage flux, high rare-earth PM usage, PMFSM is subjected to slot effects due to presence of both PM and CAW in stator and partial saturation due to double salient structure which generates cogging torque (T cog ), torque ripples (T rip ) and lower average torque (T avg ). To overcome aforesaid demerits, this paper presents Partitioned PM (PPM) Consequent Pole Flux Switching Machine (PPM-CPFSM) with flux barriers to enhance flux modulation, curtail PM usage and diminish stator leakage flux which reduces slotting effects and partial saturation to ultimately reduces T cog and T rlp . In comparison with the existing state of the art, proposed PPM-CPFSM reduces 46.53% of the total PM volume and offer T avg higher up to 88.8%, suppress T rlp maximum up to 24.8%, diminish T cog up to 22.74% and offer 2.45 times T den and P den . Furthermore, torque characteristics of proposed PPM-CPFSM is investigated utilizing space harmonics injection i.e. inverse cosine, inverse cosine with 3 rd harmonics and rotor pole shaping techniques i.e., eccentric circle, chamfering and notching. Detailed electromagnetic performance analysis reveals that harmonics injection suppressed T cog maximum up to 83.5%, T rip up to 40.72% at the cost of 4.71% T avg . Finally, rotor mechanical stress analysis is utilized for rotor withstand capability and 3D-FEA based Coupled Electromagnetic-Thermal Analysis (CETA) for thermal behavior of the developed PPM-CPFSM. CETA reveals that open space along PPM act as cooling duct that improve heat dissipation.

Direct Torque Control (DTC), a superior technique, which controls the stator flux and electromagnetic torque of an electrical machine. In spite of its numerous advantages, it possesses certain shortcomings like torque ripples, flux ripples, variable switching frequency and problems during the startup conditions. Recently, Matrix Converters (MC) have emerged as an efficient alternate for the Voltage Source Inverter employed in the DTC technique, which is capable of providing flexible and dynamic control over the torque and flux ripples associated in a machine. In this paper, a review on different control techniques associated in implementing the Matrix Converters for DTC method are categorized as follows: Subdivision of MC Voltage Vector method, SVM (Space Vector Modulation) based MC-DTC method, MC-DTC Duty Cycle Control, Employing Rotational Vectors of MC and Model Predictive Torque Control method. The pros and cons of each matrix converter fed direct torque control methods are presented by analyzing the experimental results from the literature. [ABSTRACT FROM AUTHOR]

The reduction in cogging torque enables smooth operation and an increase in the torque density of the machine. This research aims to minimize cogging torque in dual rotor single stator axial flux permanent magnet (AFPM) machine. Reduction in cogging torque makes the back EMF sinusoidal and reduces the torque ripples in AFPM machine. In this paper, an elliptical trapezoidal-shaped permanent magnet (PM) is proposed to minimize torque ripples of the AFPM machine. The 3D finite element analysis (FEA) is used for the analysis of AFPM machine. The optimization of AFPM machine is done by employing the asymmetric magnet-overhang along with the parameters of elliptical-shaped PM using Genetic algorithm (GA). [ABSTRACT FROM AUTHOR]

Torque smoothness is a strict requirement for synchronous reluctance motor (SynRM) industrial applications. The speed fluctuations induced by the high-frequency and low-frequency torque ripples deteriorate the drive performance. To suppress high-frequency torque ripples chronically omitted by conventional high-frequency signals injection methods at low-speed operation, this article proposes a bi-axes high-frequency signals injection (Bi-HFSI) scheme. A novel signal injection method is adopted, and the torque power spectrum can be broadened with discrete peaks effectively suppressed. In addition, aiming at decreasing low-frequency torque ripples, the Fourier iterative learning control algorithm that is effective in suppressing periodic disturbance is applied. It is combined with the Bi-HFSI scheme which mainly limits torque ripples at low frequencies including 1st, 2nd, and 6th harmonics. Theoretical analysis is presented, and the proposed method is verified by experiments on a 3-kW SynRM drive platform. [ABSTRACT FROM AUTHOR]

The effect of power supply and/or motor asymmetry on the phase-load distribution and the ripple of electromagnetic torque in a polyphase drive is studied by the method of symmetrical components. It is shown that the presence of asymmetry causes the mapping of all harmonics in the supply voltage into all planes of symmetrical components and eliminates the possibility of independent control of harmonics. The dynamic model of a five-phase squirrel-cage induction motor demonstrates that even minor phase or amplitude asymmetry causes asymmetry in the phase load and ripple of the electromagnetic torque. Their level eliminates the possibility of continuous operation of the motor in this mode and requires the use of control systems that provide load balance in the intact phases. [ABSTRACT FROM AUTHOR]

This article proposes an optimal scheme for an interior permanent-magnet synchronous motor (IPMSM) in electric vehicle drive system using novel model predictive torque control (MPTC) algorithm. A single optimal voltage space vector (VSV) is applied with a two-level voltage source inverter in the conventional MPTC. An improved MPTC is presented to reduce the drawbacks with satisfied torque reaction performance without adding the sampling time. First, set switching table to alleviate the calculated complexity which decreasing the selection of the appropriate VSVs. Second, optimize the duty cycle to restrain the torque ripple. Finally, the conventional MPTC and the proposed MPTC are compared in the aspects of torque and flux ripples, current harmonics, and computational level in the experiment using dSPACE. [ABSTRACT FROM AUTHOR]

The direct torque control (DTC) of permanent magnet synchronous motor (PMSM) drives is a noticeable practice in industrial applications due to its quick dynamic performance. However, due to the presence of hysteresis controllers and inaccurate switching tables especially for the multilevel fed DTC drives are facing higher ripples in torque and flux response. An improved DTC for three‐level open‐end winding PMSM drive is proposed in this article and features reduction of flux and torque ripples. The torque and flux performances of the PMSM are directly controlled by the calculated reference voltage vector in the stationary reference frame. The voltage vector tables are proposed based on the length of the voltage space vectors and the actual voltage vector nearer to the calculated reference voltage vector is selected so that the minimum ripples exist in flux and torque responses. The steady‐state and dynamic conditions of the proposed DTC method are verified in the real‐time experiment and also compared with the conventional DTC as well as the recently developed control methods. [ABSTRACT FROM AUTHOR]

This study presents an extremum seeking‐proportional–integral and derivative (ES‐PID) controller design for brushless direct current motors and its implementation in electric vehicles. The ES‐PID controller aims to simultaneously maintain a speed set‐point and reduce torque ripples in the presence of load‐torque disturbances. The proposed ES‐PID combines the simplicity of a PID controller with an extremum seeking approach, a model‐free optimisation approach, thereby resulting in an optimal controller that can be realised on simple hardware (with limited computing power and memory). In addition, a theoretical analysis of the proposed ES‐PID control scheme in terms of stability and convergence is also presented. Performance evaluation of the proposed ES‐PID controller using both simulations and hardware experiments are presented. The results clearly illustrate the ability of the controller to track speed set‐point and reduce torque ripples in the presence of load‐torque variations. [ABSTRACT FROM AUTHOR]

In recent decades, switched reluctance motors (SRMs) have been attracting increasing attention as a promising type of traction motors for electric vehicle propulsion, owing to their robust construction, elimination of permanent magnets. However, their phase inductance profile contains significant high-order harmonics, which generates input-current and torque ripples under SRM drive with the conventional square phase-current waveform. This study solves this problem by proposing a novel phase-current waveform in replacement of this square waveform. The proposed waveform is a predetermined waveform that can be stored as a look-up table in the inverter controller and can be magnified or attenuated to adjust the output torque, similarly as the conventional square waveform. Certainly, SRMs generally exhibit magnetic non-linearity due to magnetic saturation, which complicates the analysis. Therefore, the proposed waveform is analytically derived under the assumption that the magnetisation of the motor remains below the saturation level because vehicle propulsion tends to require a torque output far smaller than the maximum rating of the motor in normal vehicle travel. The proposed phase-current waveform is experimentally tested in comparison with the conventional square phase-current waveform. Consequently, the proposed waveform revealed smaller ripples in both the input-current and torque, supporting the effectiveness of the proposed phase-current waveform. [ABSTRACT FROM AUTHOR]

This article proposes a fault-tolerant field-oriented control strategy for five-phase surface-mounted permanent magnet synchronous machine with non-sinusoidal back electromotive force under double-phase open-circuit fault, where the failure phases are either adjacent or nonadjacent. Based on the decoupled mathematical model after failure, the optimum current references which satisfy the zero-torque-pulsation constraint at the synchronous frame are presented. However, the torque operation range is small. So a full-range minimum torque ripples post-fault strategy is proposed. This strategy extends the torque operation range by gradually relaxing the zero-torque-pulsation constraint. And it can minimize the torque ripples for each torque reference value in the whole torque operation range. The synchronous frame proportional integral resonant controllers and carrier-based pulsewidth modulation are employed to implement the proposed post-fault strategy. The experimental results are provided to verify that the proposed strategy can achieve wider torque operation range and smaller torque ripples compared with the conventional fault-tolerant strategies. [ABSTRACT FROM AUTHOR]

The performance of the conventional model predictive current control (MPCC) method is not without steady‐state ripples in electrical drives. Although some recently proposed MPCC methods have succeeded to mitigate this drawback, they have led to reductions in the dynamic speed response inherent to the conventional MPCC method. An improved MPCC is proposed here which would enhance the conventional MPCC method without any side effect on its merits. In this proposed method, three control strategies are presented for transient‐ and steady‐state operations. The first two strategies are applied to improve motor performance in the steady state, through calculating the voltage vector (VV) and its optimal duration to minimise ripples in both d–q ‐axis currents. The third strategy is applied in the transient‐state operation, where, instead of two VVs, an allowable non‐zero VV is applied throughout the control cycle to prevent dynamic response reduction caused by zero VV. The experimental results confirm the effectiveness of this proposed method in reducing torque ripples, flux ripples, and the stator current total harmonic distortion in relation to those obtained by the previous MPCC methods. [ABSTRACT FROM AUTHOR]

Recently, Direct Torque Control (DTC) of AC motors is considered a significant method to attain torque control behavior compared to DC motors. However, it still suffers from some drawbacks such as the large torque and current ripples. Choice of hysteresis band amplitude is one of the initial difficulties involved in the technique since it determines ripple frequencies and amplitude error of control variables. This paper presents a comprehensive analysis of hysteresis band variations in DTC on the dynamic performance of induction motor (IM) drives. In this concern, effects of flux and torque hysteresis bands on switching frequency, torque and flux ripples as well as current distortion are explored. A simulation model is implemented by Matlab/Simulink. An experimental system of DTC for IM drives using DSP-DS1102 is built and tested. Experimental results are captured to prove the simulation results. The results show that the proposed DTC exhibits a good performance with minimum torque ripples and low current distortion under small hysteresis band amplitudes. However, small hysteresis band amplitudes produce high switching frequencies which cause high switching losses and high computation burden. To guarantee a high dynamic performance DTC of IM drives, a fuzzy logic controller (FLC) instead of a PI speed controller is designed. [ABSTRACT FROM AUTHOR]

The electrical drive systems utilized in Electric Vehicles (EVs) applications must be reliable and high performance. To providing these specifications, it is essential to design high-efficiency electric motors and develop high-performance controllers. This study introduces direct torque control of Switched Reluctance Motor (SRM) for electric vehicle applications using Model Predictive Control (MPC) technique. The direct torque control using MPC is proposed to maintain the motor torque and motor speed to tracking desired signals with a satisfactory response. In this study, the MPC algorithm was programmed in C- language, and the simulation tests were performed using a non-linear model of 6/4 - 60 kW SRM that is fed with the symmetrical converter. The proposed controller was tested under different load conditions to verify the robustness of the controller, as well as at variable speeds to investigate the tracking performance. Thanks to the proposed method, the SRM torque ripples, stator copper losses, and average switching frequency of the power converter can reduce effectively due to applying a cost function that combines multiple objectives. The obtained outcomes show the effectiveness of the suggested approach compared to conventional direct torque control techniques. [ABSTRACT FROM AUTHOR]

Copyright of Przegląd Elektrotechniczny is the property of Przeglad Elektrotechniczny and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

This paper proposes a straightforward second-order sliding mode control (SMC) approach to minimize current distortions and torque ripples of a switched reluctance motor (SRM). In the first step, conventional SMC is briefly recalled and detailed. Then, a special attention is paid to the synthesis and the implementation of a second-order (SM2) approach. Stability analysis of these two approaches is ensured. It will be shown that the proposed second-order SM approach offers a lower harmonic distortion of the motor currents, a reduction of the torque ripples, and the elimination of chattering phenomena. The effectiveness of the proposed SM2 is verified by simulation results then validated by experiments. [ABSTRACT FROM AUTHOR]

The polyphase machine provides increased reliability by enabling operation with one or more phases in fault, and the most common faults are stator fault, it's for that a new analysis model of stator open phase faults in a five-phase induction motor has been presented in this paper. A new modeling of five phase induction machine in natural frame is elaborated, and the performance of five phase induction machine was analyzed under stator open phase using the principal component analysis (PCA) method. The PCA is a tool to reduce multidimensional data to lower dimensions while retaining most of the information, where the effect of the fault conditions caused by open phase on electromagnetic torque, mechanical speed, stator current and efficiency of this motor has been investigated. The findings of this research may be useful and help researchers who are interested on the fault tolerant control to minimize or eliminate this effect. [ABSTRACT FROM AUTHOR]

Hall sensors provide significant commutation signals for brushless DC (BLDC) motors. However, installation errors of Hall sensors are almost inevitable for BLDC motors, which can lead to commutation errors, further current ripples and torque ripples. Meanwhile, abnormal diode conducting in inactive phase can be aroused by large commutation errors at high speed. Therefore, the commutation errors make a negative influence on motor efficiency and degrade the performance of BLDC motors. Here, a simple and fast method to estimate the commutation error is proposed. Based on the analysis of the commutation process under commutation error, only the turn‐off phase current at the commutation instant is required for the estimation of delayed commutation error, while only the time interval of the turn‐off phase current decreasing to zero after commutation instant is needed when advanced commutation occurs. In order not to affect the dynamic performance of a BLDC motor, this study utilises a straightforward compensating method of commutation error. The experimental results represent that the proposed method is effective at different speeds, load torques, and under load‐variation with good transient performance. [ABSTRACT FROM AUTHOR]

Smart, Micro and Nano-grids are the future of electric power systems. In parallel with this future, electric vehicles (EVs) take a great deal of attention, as they are one of the important elements in these systems. Also, with the passage of time, the development continues in the technology of manufacturing EVs. Since the electric motor is the main component in these vehicles, research and development is continuing to find the most suitable motors that can work in such vehicles. The synchronous reluctance motor (SynRM) is the newest motor used in this industry. SynRMs faces different challenges, one of which is the torque ripples. Different trials were used to reduce or eliminate or minimize these ripples. Most of previous work focuses on the SynRM design parameters to reduce torque ripples. In this paper, the control methodology and the strong action controller (SAC) are used as a tool to reduce these ripples. The simulation results showed the effectiveness of the application of the proposed SAC in ripples factor reduction. This reduction represents a new contribution over the already existed techniques. [ABSTRACT FROM AUTHOR]

Magnetic gears offer significant advantages such as low noise and vibration level, lower maintenance and higher reliability compared to mechanical gears and are suitable for many applications in the industry. The coaxial magnetic gear has been extensively discussed in the literature, since it achieves higher torque densities amongst other magnetic gear configurations. The magnetic field is generated by permanent magnets mounted on the two rotors and a modulator between them. The modulator consists of ferromagnetic segments that are typically encased in a resin in order to increase its stiffness without compromising the generated magnetic field. However, due to the development of radial forces, oscillations of the ferromagnetic segments occur, which lead to torque ripples that affect the operation of the coaxial magnetic gear drive in applications where accuracy is required. This work introduces a computationally lightweight analytical 2D model in order to determine the applied radial force on the ferromagnetic segments at each angle of rotation of the two rotors and henceforth calculate the displacement of these segments using FEA. In this way it is possible to assess the variation of the torque (ripple) versus the angle of rotation of the input or output shaft. A parametric investigation examining the influence of the ferromagnetic segment thickness on the resulting torque ripple of a specific drive was carried out illustrating the benefits of the analytical models developed herein.

This paper presents the implementation of direct torque control (DTC) algorithm on the symmetrical six‐phase (0° displaced) induction motor supplied by nine‐switch inverter (NSI). This configuration provides the better dc bus utilisation in comparison to symmetrical 60° displaced and asymmetrical six‐phase induction motor. In the conventional topology, 12‐switch two‐level inverter is required to control the drive where total 64 switching states are available. In the proposed system, NSI is used to drive the motor which is having 27 switching states. The DTC algorithm is proposed with five‐level torque comparator by using large, small and zero voltage vectors for reduction in torque ripples. The elimination of xy‐subspace flux without affecting the merits of conventional DTC is achieved by using redundant switching states of the inverter. The experimental results under steady‐ and dynamic‐state operation are provided with DTC algorithm on 0° displaced symmetrical six‐phase motor supplied by NSI to validate the effective controlling. [ABSTRACT FROM AUTHOR]

The unbalance between parameters of multiphase induction motors is mainly resulted from the variation in the first-phase resistance of stator and rotor. This paper aims to examine the performance of five-phase induction machine with unbalanced parameters. First, a model was set up for the five-phase induction machine, which can efficiently identify the defects in natural frame of the machine. Then, five-phase induction machine were simulated in difference scenarios on Matlab/Simulink. The variations in stator and rotor resistance were measured, and their impacts on several performance indices were analyzed in details. The results show that the variations directly affect the torque ripples, Joule losses, and mechanical speed of the fivephase induction machine. The research findings indicate the possibility to eliminate this effect through fault-tolerant control. [ABSTRACT FROM AUTHOR]

Five-phase permanent magnet synchronous motors offer merits of high fault tolerant capability and high torque per rms ampere and, thus, are suitable for applications, such as aerospace and electric vehicles. However, the complex machine model causes difficulties in controller design. Besides, having 32 voltage vectors with various effects on currents and torque, the selection of the optimal switching state becomes a challenge to achieve a performance tradeoff. This paper proposes an improved model predictive direct torque control (MPDTC) strategy consisting of a quadratic evaluation method (QEM) and a harmonic voltage elimination method (HVEM). In QEM, the preliminary vector is first chosen from the vectors of the outer decagon according to a cost function for torque and flux regulation. This preliminary vector, composed of three sets of different amplitudes, is further synthesized according to the error between the actual torque/flux and the references. In this way, the optimal voltage vector can be obtained without significantly increasing the computational burden. In HVEM, by subtracting the harmonics voltage component from the vector determined previously in QEM, the final voltage vector is obtained for mitigating stator harmonic currents. The proposed control strategy is compared with the conventional MPDTC approach. The results confirm the effectiveness of the proposed methods with good steady-state performance while maintaining quick dynamic responses. [ABSTRACT FROM AUTHOR]

The research work proposes, Design and implementation of Solar power fed permanent magnet synchronous motor using improved DC-DC Converter and modified p-q theory based shunt active filter for reducing vibrations in drive for Industrial Applications. The Proposed research consists of both buck and boost converter, linking dc voltage unit and works in discontinuous conduction for boosting the battery life time. The improved converter provides multiple output capability using B4-inverter which reduces the cost of a proposed system considerably. In addition, for the reduction of harmonics in three phase system modified p-q module is enhanced. Comparing with the existing module, modified p-q module act as a triggering module for inverter to reduce harmonics in three phase systems and vibration across the motor, moreover the structured circuit would result in reduction of total harmonic distortion (THD), torque ripples, compact power switches, DC source reckoning and reduced starting current. The simulation of buck boost converter is considered, and its performance parameters were analyzed for different operating conditions. Thus, for industrial applications, the bidirectional converter and inverter fed permanent magnet synchronous motor drive is employed with the reduction in vibration, which is more efficient than conventional method. Here both simulation and experimental setup has been employed with a satisfying closed loop performance. [ABSTRACT FROM AUTHOR]

Abstract It is well-known that switched reluctance motor, as a non-linear load, is a source of current ripples which reduces the life time of proton exchange membrane fuel cells and significantly affects their performances. In this work, optimal operations of autonomous stacked proton membrane fuel cells serving a switched reluctance motor are anticipated. Overall model comprising proton exchange membrane fuel cells stack and switched reluctance motor along with necessary interface and control elements are implemented using MATLAB/SIMULINK. Three key objectives are adopted to be optimized either individually or simultaneously such as: i) proton exchange membrane fuel cells stack efficiency, ii) torque per ampere ratio, and iii) torque smoothness factor. Six decision controlling parameters e.g. fuel cells' temperature, air flow rate, air pressure, fuel pressure, and turn on/off angles of switched reluctance motor represent the search space of dragonfly algorithm. Numerical results indicate that the proposed dragonfly algorithm-based method is capable of increasing proton exchange membrane fuel cells stack energy saving, and reducing of hydrogen consumption, ripples in switched reluctance motor torque and current of proton exchange membrane fuel cells stack. Finally, results generated by the dragonfly algorithm are appraised compared to those obtained by genetic algorithm which signifies its value. Highlights • Three objectives are targeted to improve the overall hybrid system performance. • Dragonfly algorithm gives the optimal settings of the six adapted control variables. • Various operating scenarios are demonstrated for the proposed methodology. • The results indicate that ripples and fuel consumptions can be enhanced. • Comparisons to others are made to signify the proposed method. [ABSTRACT FROM AUTHOR]

Cogging torque in flux‐switching permanent magnet (FSPM) machines dominates the whole torque ripples due to its special doubly salient structure and high air‐gap PM flux density. In this study, the chamfering method of right angles is utilised in both stator and rotor sides of FSPM machines to suppress the cogging torque. First, an analytical expression of cogging torque, taking the influence of the introduced right angles into consideration, is derived. On the basis of the derived model, the optimal dimensions of right angles are obtained and verified by both finite element analysis and experiments. Besides, the impacts of the proposed technique on phase electro‐motive force and electromagnetic torque are also evaluated. The predicted results indicate that the proposed technique can significantly reduce cogging torque in FSPM machines with negligible reduction of average torque. [ABSTRACT FROM AUTHOR]

The study proposes a parameter optimisation of the high‐frequency (HF) signal injection sensorless algorithm applied to an interior permanent magnet synchronous machine (IPMSM). The latter is intended for electric vehicle (EV) traction applications with dedicated mission profile under specific constraints. This optimisation aims to minimise two conflicting objectives: (i) minimising the position estimation error which impacts the torque accuracy and (ii) minimising torque ripples responsible for additional stress on the motor shaft, causing unwanted noise in the vehicle powertrain. The main contribution of this study is to provide guidelines for the selection of the HF signal injection tuning parameters so as to satisfy these objectives. To do so, a genetic algorithm has been implemented and the optimisation process is based on a reliable simulation model. Using a simulation model is deliberately chosen in order to reflect the behaviour of a motor series. Besides, in order to integrate the specificities of the target application, the optimisation process is based on a typical EV mission profile. A set of non‐dominated solutions satisfying the tradeoff between the position error and the torque ripples is obtained, discussed and finally tested with success on an experimental setup. [ABSTRACT FROM AUTHOR]

The harmonic contents of principal performance characteristics in an electrical machine are important due to several reasons, especially because they influence the machine acoustic noise generation capability. Therefore, they should be accurately calculated considering the various electromagnetic effects involved in the machine operation. Accordingly, this study proposes a detailed analytical model for predicting the time waveforms and harmonic contents of the principal performance characteristics of a double‐sided TORUS‐type non‐slotted axial flux permanent magnet motor with surface‐mounted magnets at steady state under any given loading conditions. The armature‐reaction magnetic field and inductances are exactly calculated considering both the effects of coil sides and end windings as well as that of the winding distribution. Most notably, the aggregate iron loss of machine and its influence on armature currents is precisely modelled based on the magnetic field distribution in iron parts. By establishing and solving the differential equation system of motor in the two cases with or without the neutral wire, the armature currents, speed and torque ripples, input/output powers, and copper and iron losses are all achieved with the entire harmonic content and highest accuracy. The comparison of results with those of finite element analysis and real test then validates the model. [ABSTRACT FROM AUTHOR]

With the increasing popularity of hybrid electric vehicles (HEVs), the demands of improving the fuel economy and energy efficiency of HEVs are enlarged. The technology electrical continuously variable transmission (E-CVT) system provides the opportunity to fulfill this requirement. However, conventional E-CVT with planetary gears suffer from frictional loss, high maintenance, and audible noise. Therefore, a series of gearless E-CVT propulsion systems are developed. Thereinto, a double-rotor single-stator brushless E-CVT having high torque density, reduced stator end winding length, and reduced copper loss was recently proposed. However, only torque of the E-CVT system is optimized by the genetic algorithm in the previous study. This paper adopts a differential evolution algorithm coupled with finite element method to optimize torque, energy efficiency, torque ripples, and multiobjective of the E-CVT system by reconfiguring the height of rotors, the areas of slots, and the height of yoke. It is simulated that by only tuning the weighting factors, the permanent magnetic machine in the E-CVT system can operate in the highest torque mode, highest energy efficiency mode, lowest torque ripples mode, and multiobjective optimization mode. [ABSTRACT FROM PUBLISHER]

This study presents the analysis and experimental verification of a coaxial magnetic gear (CMG) for speed‐change transmission. The key design of this CMG is to adopt a stationary permanent‐magnet (PM) ring between the inner and outer rotors, aiming at removing the PMs and only retaining the salient‐pole‐iron on the outer rotor to improve its mechanical reliability. Meanwhile, due to a large equivalent magnetic clearance promoting low torque ripples, the proposed CMG can offer the advantages of achieving a consistent speed ratio and stable transmission within the entire pull‐out torque range. By using the two‐dimensional finite element method, the detailed parametric analysis and static characteristics of the proposed CMG are performed to set up its design criteria. Moreover, a quantitative comparison with a conventional CMG is conducted, and a prototype is also fabricated for experimentation to verify the validity of the proposed CMG. [ABSTRACT FROM AUTHOR]

For the last few years, predictive torque control (PTC) has attracted the attention of the researchers due to its simplicity and effectiveness. In PTC, flux-weighting factor needs to be wisely adjusted since it affects greatly the performance of the drive system. Many research trials were devoted to select this weighting factor or even eliminate it. Each of these trials illustrates a method to overcome this problem and presents a solution to the conventional weighting factor calculation method. This paper presents a critical evaluation of the performance of recently proposed methods for weighting factor selection for finite control set PTC. Based on the way the weighting factor is calculated, the methods are classified to offline and online methods. In this study, more focus will be directed to the evaluation of the online methods since they can update the weighting factor automatically if the operating point changes. Specifically, four recently developed methods along with the conventional method are considered in this study. Flux ripple, torque ripple, current total harmonic distortion, and average switching frequency are adopted as the judging criteria for this comparison. Simulations at different operating points are used to assess the performance of each method, and the characteristics of each method are compared according to the performance indices suggested. The strengths and weaknesses of each method are highlighted. Therefore, the suitable method can be identified according to different application requirements. [ABSTRACT FROM AUTHOR]

This paper presents the development of the commutation time estimator (CTE) for PM BLDC motor drives. The proposed scheme is aimed to enhance motor output torque by minimizing the generated torque ripples. The torque ripples originating from commutation instances cause spikes and dips in the motor output torque. The motor output torque could be enhanced by mitigating the phase current mismatch rate during phase current commutation period. This rate could be almost matched by introducing the commutation time estimator (CTE) in order to control the rate of the energized phase current to be matched with the de-energized phase rate. Results obtained have validated and verified the proposed CTE effectiveness with a 50% average reduction of the generated torque ripples in PM BLDC motor.