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In wind energy systems, it is necessary to have a good knowledge of the used generator and its parameters. Despite the motor manufacturer's specifications, accurately estimating the machine parameter reference values is critical for the perfect control system. In this context, off-line identification tests of a 3 kW permanent magnet synchronous machine were conducted to determine the mechanical and electrical parameters. In addition, this research exploits a meta-heuristic optimization technic dubbed grey wolf optimizer in the on-line parameter's identification field. The estimate method is focused on the parameter's estimation linked to a reference model. The rule is based on the cancelation of the current error among the measured and the associated estimated current. For each measurement, the grey wolf estimator adapts the reference model parameters until the model response and the accurate response be similar. All were implemented using the real-time interface of the DSpace DS1104 Controller card while using the ControlDesk graphical user interface and the Simulink/MATLAB environments. Results from hardware simulation confirm the efficacy and benefits of the suggested strategy. [ABSTRACT FROM AUTHOR]

Synchronous Reluctance Motors (SynRMs) have become very attractive alternatives to induction motors which have been widely used in industry in recent years. Axial-flux motor (AFM) structures have been studied in the literature as a new field. However, studies on axial-flux synchronous reluctance motors (AF-SynRMs) are very limited. In this study, optimization of an AF-SynRM has been performed to achieve optimal motor performance. In addition, the effects of the permanent magnets (PMs) have been investigated. In this design, PMs have been placed in the barriers using eight different ways, and motor performance has been examined. The placement of magnets on the barriers that are close to the air gap has an increasing effect on the average torque. However, the distorting effect on the torque ripple is seen to be quite high. In particular, the placement of magnet on all barriers improves the machine performance significantly. The negative impact on torque ripple is also low. Therefore, this study aims to provide guidance to researchers working on the design of AF-SynRMs, especially with PMs. [ABSTRACT FROM AUTHOR]

Remarkable characteristics like simple structure, high starting torque, simple maintenance, good efficiency at all speeds and cost-effectiveness have made switched reluctance machines (SRMs) suitable candidates for electric cars, electric bicycles and variable speed applications (VSAs) such as wind turbines. In this paper, a three-phase Outer-Rotor SRM (ORSRM) with 6 stator poles and 10 rotor poles (6/10) for VSA has been investigated. Unlike conventional SRM structures such as 6/4 and 12/8, an SRM model with higher number of rotor poles can reduce torque ripple much more effective than conventional SRMs. First, the SRM design is done accurately, then, by changing some parameters, the sensitivity analysis is performed on torque ripple and average torque. Finally, the optimisation process on the geometry and structural dimensions of the SRM like rotor pole arc, stator pole arc, rotor yoke thickness, rotor pole height, rotor diameter and the number of turns per phase are executed to minimise the torque ripple and maximise the average torque via genetic algorithm (GA). The initial design, optimisation and performance of the proposed model are validated via a 2-D finite element method (FEM) technique by ANSYS-Maxwell. [ABSTRACT FROM AUTHOR]

This article aims to simulate natural gas vehicle (NGVs) refueling station located in Bucharest, which includes an on-board cylinder, reservoir tanks, connecting pipes, and a reciprocating compressor using thermodynamic analysis. Tanks' pressures during the filling process were changed: 180-200, 200-220, and 220-235 bar for low, average and high pressure respectively. Furthermore, sensitivity analyses were implemented to study changing the cylinder initial pressure and the influence of vehicles' number alteration. The simulation result for mass flow rate is close to the experimental measurements. Additionally, the higher the initial pressure inside vehicle tank, the lower mass delivered and the shorter loading time. Finally, this study helps the government to increase the environmentally friendly fuel in the local market. [ABSTRACT FROM AUTHOR]

This manuscript proposes an optimization technique for electric vehicles (EVs) operated through solar photovoltaic (PV) panels by enabling the drive of a switched reluctance motor (SRM) and an enhanced cascaded converter (ECC). The proposed method is an improved Tunicate Swarm Algorithm (ITSA). The Lévy flight distributions are emerging at the conventional Tunicate Swarm Algorithm (TSA) in the modified Tunicate Swarm Algorithm, which enhances the capabilities of diversification searching and avoids the potential for stagnation. The major objective of the proposed method is to minimize the ripple present in the supply current and give optimal photovoltaic power extraction to the solar module. The proposed enhanced cascaded converter method consists of a single main converter and one auxiliary converter combined as a series structure for the distribution of minimal voltage across the switch to restrict the switch stress of dv/dt. These quantities of error are lessened by the controller of Proportional–integral; the PI gain controller is tuned to the error and provides a reference current signal by using the proposed method. An optimum voltage gain and continuous input current minimize the impact of less solar irradiation in EV applications. Finally, the performance of the proposed method is implemented in the MATLAB platform and compared with existing methods. [ABSTRACT FROM AUTHOR]

In this study, the issue of simultaneous fault detection and control (SFDC) for a class of switched linear systems with input and state delays is being addressed. A detector/controller unit (dynamic observer/observer-based controller) is suggested for a residual generation that simultaneously takes into account the control and fault detection objectives using specific performance indices. It is assumed that the delay will fluctuate within a range with a lower bound that is not zero. Based on a Lyapunov–Krasovskii functional (LKF), and thanks to the free-weighting matrix and projection lemma, a new sufficient condition for developing a new method is put forth in terms of a set of linear matrix inequalities (LMIs). To illustrate how well the suggested results work, the proposed method is applied to a vehicle roll dynamic. [ABSTRACT FROM AUTHOR]

In this study, a high-power synchronous reluctance motor (SynRM) was designed for the traction motor of electric vehicle (EV) and its double-stage optimization was performed. Genetic algorithm and sensitivity analysis methods were used to obtain the best design parameters. Double-stage optimization was carried out to minimize the torque ripple and obtain the targeted torque, speed, and power values of the SynRM. In the first stage, the genetic algorithm method was used to improve the design parameters of the stator and rotor. With the improved design parameters, it was observed that the torque ripple decreased. In the second stage, the sensitivity analysis method was used. In this method, the effect of changing the skew angle of the stator on the torque ripple was investigated. The performance of the designed motor was examined in the optimization process. It was observed that the targeted torque, power, speed, efficiency, and torque ripple minimization values are successfully achieved with the best stator and rotor parameters. The results showed that SynRM produces high torque and high power with high efficiency and low torque ripple over wide speed range. It is quite proper to use the designed SynRM as a traction motor of new generation electric vehicles. [ABSTRACT FROM AUTHOR]

Energy resources are decreasing in the world and the use of electrical machines is increasing. Motor design and development studies are carried out to reduce the losses and increase the efficiency of motors, which are widely used especially in industry. In this study, Line Start Synchronous Reluctance Motor (LS-SynRM) was designed by taking an induction motor, one of the most widely used motors in the industrial field, as a reference. With its rotor cage structure feature, it can be line-start without the need of a driver. The rotor has a lot of design variables due to slots and barriers. Sensitivity analysis was used to determine the effect of design variables on performance criteria such as power factor, efficiency and torque ripple. Subsequently, Multi-Objective Genetic Algorithm (MOGA) optimization was used to find the values of the design variables that bring the motor performance closer to the optimum result. The results of the reference induction motor, initial LS-SynRM, and the optimized LS-SynRM are compared. It has been taken care to preserve the synchronization feature of the LS-SynRM and the related results are given in the analyses. It is shown that the optimized motor is in IE4 efficiency class and operates with low torque ripple. [ABSTRACT FROM AUTHOR]

Variable reluctance motor is becoming a competitive candidate among all other machines available due to its added features. The development of variable reluctance motor is simple due to the simple construction of rotor without any permanent magnets. Reduced complexity in structure paves the way for low-cost motor and it also leads to the application of SRM in a wide manner. In order that the machine could be used in various applications, it is much necessary to have a suitable driving system (converter configuration). The best choice of converter for SRM would pave the way for desirable control of the machine. The proposed work includes the design and analyses of an appropriate driver configuration for SRM and interface it with the motor which is already designed and analyzed using ANSYS Maxwell. The design and analysis of the converter are carried out using the ANSYS Simplorer tool box. [ABSTRACT FROM AUTHOR]

—In this study, the design and analysis of multi-layer fully pitched winding switched reluctance motor (MFP-SRM) for general use (submersible pump, electric vehicles, etc.) have been performed. It is seen that the multi-layer switched reluctance motor (SRM) has higher output power when compared to the single-layer SRM. In multi-layer SRM, the motors in the layers are electromagnetically independent of each other although they are identically the same motors with the same characteristics in terms of performance and geometry. Each layer of the MFP-SRM which is designed in this study consists of a 6/4 pole fully pitched SRM (FP-SRM) and these motors are magnetically independent of each other. In the MFP-SRM, which is designed as a double layer, there is a 15° phase difference between the rotor position angles and torque profile curves of each layer. With the phase difference that changes depending on the number of layers, each layer contributes to the total torque production of the profile, ensuring a smooth profile. According to the results of the 3D FEM analysis, it is seen that the proposed multi-layer motor structure has high starting torque and low torque ripple properties. In the analysis carried out in the range of 3–15 Amperes, the torque ripple of the traditional FP-SRM varies between 31.99% and 38.19%, while the torque ripple of the proposed MFP-SRM only varies between 3.23% and 7.11%. [ABSTRACT FROM AUTHOR]

This study presents an enhanced AC drive for the SynRMs coupled with a circulation pump (CP) and an improved control system based on the field orientation. A grid-fed 900 W motor driver consisting of an electromagnetic interference filter (EMI), power factor correction (PFC), and three-phase inverter is designed to drive 0.75 kW SynRM. A boost PFC converter is designed as an interface between the AC power line and the motor drive. PFC is used to recover the bad power factor performance of the SynRM. In addition, the boosted and well-regulated DC-link voltage improves the motor driving performance. Control strategies and practical implementation based on the field-oriented control of synchronous reluctance motors are presented. Dynamic and steady-state responses of the CP SynRM drive in various conditions are verified experimentally. Low current and voltage ripples, unity power factor, maximum torque per ampere with low fluctuation and low EMI noise are achieved with the low cost efficiently. All of the improvements are obtained by fewer circuit elements and higher energy conversion efficiency. The advantages of using SynRMs in dry-rotor circulation pumps for heating applications have been demonstrated experimentally. [ABSTRACT FROM AUTHOR]

This paper investigates the aperiodic sampling stabilisation problem for a class of switched linear systems under asynchronous switching. Based on a novel dynamic sampling rule, a sampling-point-based partition-dependent discontinuous Lyapunov functions control approach are developed to make the considered closed-loop switched systems be globally asymptotically stable. Compared with the existing results, the proposed control method permits frequent switching in a sampling interval for subsystems. But the frequent information transmission to the matched controllers and the negative effect of long asynchronous running on system performance can be nicely handled in this paper. Moreover, the partitioned Lyapunov functions are allowed to increase in some segments of the synchronous operating intervals. Tighter synchronous duration and switching number which are determined by more than affine functions make the switching signal more flexible. Finally, simulation analyses of two examples show the advantages of the developed control strategy. [ABSTRACT FROM AUTHOR]

SRMs have high torque ripples. Modifying the stator and rotor shape of SRMs is one of their methods to remove torque ripples. In this study, new rotor and stator geometries have been proposed for SRM. Performance characteristics are obtained and dynamic analyses are carried out for both novel and classical 6/4 SRMs. FFT analyses of the torque characteristics are also performed for the both SRMs. The changes in performance and the FFT results of torque characteristics are determined for both the current-controlled and uncontrolled operations in both SRMs. 23.60% and 15.20% improvements in torque ripples are achieved for the uncontrolled and current-controlled operations in SRMs respectively. When the FFT analyses are applied to the torque characteristics, the THD values are obtained as 21.19% and 8.31% in the uncontrolled and controlled motor current operations respectively. A 122 W three-phase 6/4 SRM simulation based on the MATLAB–SIMULINK environment is performed to validate the improvement of the torque ripple of the proposed model. [ABSTRACT FROM AUTHOR]

Switched reluctance motor (SRM) drives are more popular due to their attractive features as compared to other conventional motors. The overall performance of the SRM drive system can be resolved by choosing an appropriate power electronic converter. In this paper, the performance analysis of the 3-phase 6/4 SRM drive, using different power converters, is presented. The comparison is made among the different converter topologies in terms of parameters such as torque ripple, commutation time, number of power devices used, and overall cost of the drive. The results show that an asymmetric bridge (ASB) converter is best for high-performance applications. This paper also introduces a new improved ASB (IASB) converter with a minimum number of switches. The simulation results of the 6/4 SRM drive system have been carried through MATLAB/Simulink tool. An experimental prototype has also been validated and the results demonstrated that the proposed converter is more preferable than other converters. [ABSTRACT FROM AUTHOR]

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]

In this work, a quasi-impedance source (QIS) converter is employed as a front-end converter for four-phase switched reluctance (SR) motor drive. The QIS converter is used for dc-link voltage boosting and to enhance the dynamicperformance. The proposed converter can increase the power output in each stage, by increasing the excitation voltage and controlling based on the drive specifications. The demagnetisation terminal is separated from the excitation terminal, and then the voltage is increased further to achieve the quick commutation. Therefore, with the proposed converter, the SR motor can operate with higher voltages at each interval to reach the end goal of faster excitation and commutation. Thus, it eliminates the production of negative torque and reduces the torque ripple. Initially, the steady-state characteristics have been analyzed with the classical asymmetric bridge (CAB) converter and the proposed converter. According to the steady-state characteristics, the proposed converter can provide higher torque and increased power output than the CAB converter. The effectiveness of the proposed converter is validated in a MATLAB/Simulink environment and compared with the CAB converter. Finally, the experimental response is tested using Xilinx SPARTAN 6 FPGA processor and compared with the simulation results. [ABSTRACT FROM AUTHOR]

This paper reviews research reported over the last three decades on enhancing the torque density of a switched reluctance machine (SRM) through improved magnetic structure of the machine. To this effect, various pole configurations, modifications to pole geometry such as introduction of teeth in stator poles, tapering of stator and rotor poles, non-uniform airgap, introduction of flux barriers in the poles, and segmental rotor are studied. All salient points in the review are supported by comparative analyses based on finite element analysis (FEA) of candidate machine designs. Increasing the number of rotor poles and introduction of teeth in stator poles enhance the torque density at low current density, while increasing multiplicity is beneficial at high current densities. Quantum of electromechanical energy conversion per individual stroke can be increased by tapering of poles, non-uniform airgap and by introduction of flux barrier in the poles. A segmental rotor can increase the stator winding flux-linkage for a given excitation, and thereby, the torque output of the machine. [ABSTRACT FROM AUTHOR]

Learning Automata (LAs) are adaptive decision-making models designed to find an appropriate action in unknown environments. LAs can be classified into two classes: variable structure and fixed structure. To the best of our knowledge, there is no hybrid model based on both of these classes. In this paper, we propose a model that brings together the benefits of both classes of LAs. In the proposed model, called an HLA, the action switching phase of a fixed structure learning automaton is fused with a variable structure learning automaton. Several computer simulations are conducted to study the performance of the proposed model with respect to the total number of rewards and action switching in addition to the convergence rate. The proposed model is compared to both variable structure and fixed structure learning automata, and in most cases, the numerical results demonstrate its superiority. In order to show the applicability of the HLA, a novel adaptive dropout mechanism in deep neural networks was suggested. The results of the simulations show that the proposed mechanism performs better than the simple dropout mechanism with respect to network accuracy. [ABSTRACT FROM AUTHOR]

Chromium (Cr) can be either essential or carcinogenic depending on the chemical form. The aim of this study was to speciate Cr in water samples, collected from Blood and Mokolo Rivers, Limpopo Province. Water samples were collected from ten sampling sites from each river. The accuracy of the method was evaluated by employing standard reference material of trace elements in water (SRM 1643 f) before sample analysis. Total Cr and Cr(VI) in water samples were quantified using graphite furnace-atomic absorption spectrometry (GF-AAS). The concentrations of Cr in water samples collected from Blood and Mokolo Rivers were found in the range of 1.56 μg/L to 6.11 μg/L and 1.34 µg/L to 3.53 µg/L, respectively. A solid phase extraction (SPE) method based on chromabond NH2 column was used to determine Cr(VI) in water. In order to achieve separation of Cr(VI), the sample was pre-concentrated and passed through a conditioned chromabond NH2 column at a flow rate of 3 mL/min. Hexavalent Cr was selectively adsorbed onto the column and the contents were dried under vacuum. The retained Cr(VI) was subsequently eluted with two column volumes of 2 M HNO3 and diluted to a final volume of 10.0 mL. The limit of detection (LOD) was 0.105 µg/L and the percentage relative standard deviations were less than 10%. The validation of the procedure was performed by spiking standard solutions containing Cr(III) and Cr(VI) and the percentage recoveries were higher than 88%. The concentrations of Cr(VI) in Blood and Mokolo Rivers ranged from 0.13 µg/L to 1.99 µg/L and 0.13 µg/L to 0.55 µg/L, respectively. In Blood and Mokolo Rivers, although the concentrations of Cr(VI) are low, their values suggest a link with the industrial and agricultural activities in the area. [ABSTRACT FROM AUTHOR]

In this paper, two different strategies are combined to optimize the phase current control for switched reluctance motor (SRM). Firstly, considering the sampling and computation delay, a current prediction chopping control method is proposed to alleviate the current ripple during the entire excitation phase chopping process. Secondly, in order to cut down the large current ripple in the initial stage of phase current establishment and the excessive output current of the battery, a partitioned current control method is proposed to control the phase current with different control logic at different rotor zones. Finally, the two control strategies are combined to further optimize the phase current. In order to verify the proposed combined control strategy, a three-phase 12/8 poles SRM simulation model and experimental platform are built. The simulations and experiments are carried out to verify the effectiveness of the proposed control strategy. [ABSTRACT FROM AUTHOR]

Linear Motors are potential candidates for replacing traditional rotary motors in high-speed transit systems. Linear Switched Reluctance Motor (LSRM) is the widely researched motor for such applications. This paper presents a design for linear switched reluctance motor (LSRM) with an improved propulsion force profile. The proposed motor consists of moving translator for direct drive transmission, without the use of mechanical gears. The stator contains a split-teethed stator structure. The proposed motor has more translator teeth than stator teeth. This paper includes a new design methodology for the proposed combination of stator and translator. The motor is designed and analyzed using 3-D finite-element method (FEM). The proposed motor has been optimized using a parameter-based cumulative deterministic optimization algorithm (PBCDOA) for further improving the force profile. The FEM results demonstrate the effectiveness of the design procedure and better force performance of the proposed topology. [ABSTRACT FROM AUTHOR]

Alternative energy sources have impacted as the ideal choice for reducing the burden on the grid and producing clean energy for water pumping. As an alternative to conventional motors for pumping, switched reluctance motor (SRM) is promising, cost-effective and highly efficient. This paper presents artificial intelligence (AI) supported variable voltage angle control (VVAC) for indirect and direct photovoltaic (PV)-fed SRM-based water pumping systems (WPS). Proposed feedforward neural network (FFNN) and adaptive neuro-fuzzy inference system (ANFIS) models are simulated and analysed for their percentage average error and real-time execution speed in the dSPACE-1104 control board. ANFIS resulted in 1/10th reduction of execution time and improved performance accuracy in contrast to FFNN counterparts. A 4kW, 8/6 SRM model, has been developed in MATLAB/Simulink environment to validate the proposed system for both direct and indirect schemes. Further, the performance comparison of peak current, RMS current, torque ripple, and efficiency for direct and indirect PV-fed systems are presented in this work. These comparative assertions reveal the feasibility of both the methods with good performance. Moreover, a reduction in overall system size and cost with the absence of an intermediate converter, the direct method provides a reduced torque ripple as compared to the indirect counterpart. [ABSTRACT FROM AUTHOR]

This paper presents a Maximum Power Point Tracking (MPPT) algorithm using system identification (SI) for solar photovoltaic (PV) pumping system under partial shading (PS) conditions. The measurement of the PV panel current was not required for the proposed MPPT algorithm. The MPPT algorithm was developed for an electric motor with a nonlinear pump load. In this study, a high-efficiency synchronous reluctance motor (SynRM) was designed as a 4-inch submersible pump motor. The system aimed to the small-scale solar photovoltaic water pumping systems. The SynRM was designed and optimized to use at low voltage levels such as solar PV panels without requiring a boost converter. Thus, the motor could be connected directly with any low voltage leveled power supply. The motor was produced 0.55 kW power with an efficiency of 86.5%. Eight PS patterns were generated to obtain four different scenarios for analyzing of the proposed algorithm. The Maximum Power Point (MPP) was determined with high accuracy for global maximum for all PS conditions using the proposed algorithm. Thus, the motor was operated at the MPP in all conditions thanks to the developed algorithm. The overall system efficiency was obtained between 72% and 82% under these conditions. [ABSTRACT FROM AUTHOR]

This paper describes a sensorless control technique Based on current waveform detection for Switched Reluctance Motor (SRM) over full speed-range. For conventional sensorless method, the resistive drop and the back- EMF are always neglected, which may cause some errors in position determination and restrict the rotor speed-range. To overcome this problem, an improved current-slope-difference based approach is presented for sensorless starting and continuous low-speed sensorless operation. For medium and higher speeds, a current-gradient method is used for sensorless operation. Based on the proposed sensorless method, the position sensorless operation within the whole speed range of the SRM can be easily implemented. Finally, the experimental results demonstrate the validity of the hybrid sensorless approach in the full speed region. [ABSTRACT FROM AUTHOR]

For off-grid, standalone solar-fed water pumping has become a very viable option for small householder farmers. Appropriate configuration and control to suit this specific application are required. Buck, boost, and buck-boost converters are used to ensure impedance adaption between the solar PV generation and the load. However, these converters have switching harmonic problems. This problem is solved by the use of a single-ended primary inductor converter. Thus, a single-ended primary inductor converter is designed to overcome these drawbacks. Therefore, the objective of this paper is to design a single-ended primary inductive converter with a PI-like fuzzy controller. In this paper, synchronous SEPIC converter with PI-like fuzzy controller for PV-fed pumping system is modeled and designed. The system performance at different input conditions is evaluated. PI and PI-like fuzzy controllers have been compared using MATLAB/SIMULINK. PI-type fuzzy controller is less sensitive to input parameters variation than PI due to auto-tuning capability. Less than 2% output variation is recorded between 200 and 1000 W/m2 irradiance. This show that output voltage is less sensitive to the input solar radiation with this SEPIC converter control. The steady-state result obtained in speed and flow rate were 141.4 rpm and 1.56 l/s, respectively, and the voltage error was 1.4 V. Thus, PI-like fuzzy controller was used to reduce the steady-state error. The results obtained with PI-like fuzzy controller in speed and flow rate were 143.6 rpm and 1.624 l/s at 6 m head, respectively. The voltage error is 0.2 V which is less than the PI converter error (1.4 V). [ABSTRACT FROM AUTHOR]

In this paper, a novel linear switched reluctance motor (LSRM) is introduced in which the total electromagnetic losses and dimensions are significantly reduced compared to the conventional LSRMs. The LSRM's stator has a segmental structure, while its rotor possesses a seven pole configuration with three rotor poles equipped with the winding sets to generate the magnetic flux. The other remaining four rotor poles, i.e., auxiliary poles, are responsible for closing the magnetic flux path loop. In the proposed LSRM-auxiliary mover poles (LSRM-AMP), the flux path length is effectively reduced using the optimized provided auxiliary poles. Therefore, the required magnetomotive force (MMF) is reduced compared to the conventional LSRMs. In addition, as only half of the generated flux passes the stator segments, the dimensions of the stator segments and their corresponding weights are significantly reduced without any saturation issue. In order to verify the finite element (FE)-based performance prediction of the proposed structure, the electromagnetic operating principles and the design rules of the LSRM-AMP are separately investigated. A sensitivity analysis and comparative study for the proposed LSRM-AMP and conventional LSRM topologies are presented to show the performance and characteristics superiority of the optimized LSRM-AMP structure. [ABSTRACT FROM AUTHOR]

Abstract—This article presents a novel torque ripple minimization approach based on the genetic algorithm (GA) for the switched reluctance motor (SRM) drives. The fitness function of the GA is designed on the basis of two main optimization criteria. The first optimization criteria; three objectives are defined to optimize commutation angles minimizing torque ripple and copper loss. The second optimization criteria; an objective is defined to eliminate the negative torque which decreases the average torque in SRM drives. The achievement of all objectives depends on the adjusting appropriate the commutation angles of the torque sharing functions (TSF) during the commutation period. All of conventional TSFs are dependent on three different commutation angles, namely turn-on, turn-off, and overlapping. Due to the nonlinear phase inductances of SRM, the delay of current rising and falling time are not unity in overlapping commutation region. To overcome the separation of the incoming and outgoing phase currents during the commutation region, rise angle, and fall angle are used instead of overlapping angle. GA is used to optimize the commutation angles of conventional (sinusoidal) TSF and improved (sinusoidal) TSF. At the same time, the elimination negative torque effects on torque ripple, average torque, and copper loss is investigated. [ABSTRACT FROM AUTHOR]

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]

Aiming at the problem of severe unbalanced magnetic force (UMF) of the switched reluctance motors (SRMs) caused by eccentricity, this paper analyses the radial electromagnetic force's spatial distribution and frequencies under eccentricity and conduct a compensation method for the UMF. Firstly, the expression of the radial electromagnetic force under eccentricity is derived by using the method of magnetomotive force multiplying permeance, combining with the modification of the permeance. Secondly, the UMF is reduced by applying compensation current to the two stator poles of the permeance-descending phase. The selection of the stator poles and the calculation of the compensation current are decided according to the direction and the value of the unbalanced flux density. Dynamic eccentricity (DE) will produce new frequencies and spatial orders of the radial electromagnetic force, and the static eccentricity (SE) only produces the new spatial orders. The results obtained by the finite element model prove that this method can effectively reduce the UMF without sacrificing the output torque performance. [ABSTRACT FROM AUTHOR]

This paper presents four-quadrant sensorless control in switched reluctance machine (SRM) over the wide speed range. The proposed sensorless control technique could be employed not only at low speed with current chopping control (CCC) but also at high speed with angle position control (APC). At startup and low speed, the narrow voltage pulse is injected into the idle phases and the rotor position zone is determined by comparing the measured flux linkage with four flux linkage-current curves. The same flux linkage-current curves also can be adopted for rotor positions estimation at medium and high speeds. Two flux linkage-current characteristic curves in the inductance rising zone are employed to estimate the rotor position for motoring mode and the other two curves in the inductance falling zone are used to estimate the rotor position for braking mode. The experiments on a three-phase 12/8 pole SRM drive platform are carried out to verify the effectiveness of the proposed sensorless control technique. [ABSTRACT FROM AUTHOR]

This work investigates the application of the adjoint variable method (AVM) to switched reluctance motors (SRMs). A MATLAB toolbox developed by the authors estimates the sensitivities of the required objective function with respect to different geometric design parameters using at most one adjoint simulation. In this work, the AVM evaluates the sensitivities of the x and y components of the magnetic flux density, the phase flux linkage, and the electromagnetic torque of switched reluctance motors with respect to teeth height, yoke thickness, teeth pole arc angle, and teeth taper angle of both stator and rotor. The nonlinearity of the motor magnetic material is taken into consideration. The estimated sensitivities using AVM are compared with those obtained using the more accurate but time intensive central finite differences (CFD). An interior-point optimization algorithm utilizes the sensitivities of the electromagnetic torque of an SRM to maximize the motor static torque profile. Structural mapping technique is used to control the geometric design parameters through the optimization process. [ABSTRACT FROM AUTHOR]

Synchronous Reluctance Machines (SynRMs) are facing a revamped industrial interest. A comparison between SynRMs and other types of electric machines allow listing the advantages and proving the choice of such machines. This paper presents a review of SynRMs, regarding particularly their thermal analysis. First of all, a description of the basic principles of SynRM is illustrated. The thermal analysis is based mainly on the study of the heat sources and the heat extraction mechanisms which are listed and described. Nevertheless, the coupling effects between the thermal field and the magnetic material parameters are discussed. Then, the three heat extraction phenomena (conduction, convection and radiation) are analyzed. Along the work, important facts about the thermal analysis are discussed. A comparison between the different approaches used for the thermal analysis is highlighted, and new developments and perspectives are identified. [ABSTRACT FROM AUTHOR]

Here we present a comprehensive analysis of structural performance of Induction Machine (IM) and Switched Reluctance Machine (SRM) rotors under different operational conditions. Electric machines are susceptible to forces of diverse origins. In addition to traditionally considered magnetic and centrifugal forces, this article discusses independent and inclusive effects of thermal expansion and shaft attachment techniques on structural integrity of the machines. A comparative analysis of structural performance of IMs and SRMs has also been performed, under a range of scenarios, to facilitate application-specific machine selection from a structural perspective. [ABSTRACT FROM AUTHOR]

In this work, we report on the application of the adjoint variable method (AVM) to sensitivity analysis of switched reluctance motors (SRMs). Using at most one adjoint simulation, the sensitivities of the desired response with respect to all geometrical and material parameters are estimated. In this work, the AVM evaluates the sensitivities of the air region magnetic energy and the electromagnetic torque of a SRM with respect to all parameters. Good match is achieved between the AVM sensitivities and those estimated using the more accurate but computationally expensive central finite differences (CFD). [ABSTRACT FROM AUTHOR]

Although synchronous reluctance machine (SynRM) like other electrical machine has a non-linear magnetic field, the complicated structure is mathematically analyzed by analytical equations and then finite element method (FEM) simulation is utilized to validate the design. One of the well-known drawbacks of SynRM is that it has poor power factor. SynRM machine rotor design is revisited in this paper using analytical and finite element methodologies. The study focuses on highly efficient SynRM with improved power factor and excellent saturation and torque ripple effects. The rotor is designed with optimum shapes of flux barriers and then concentrates on the flux barrier dimensions, the number of flux barriers, and optimum placement of flux barriers to improving the performance parameters of SynRM. Finally, the power factor and saturation effect on SynRM are also included. This paper investigates all possible methods to improve the power factor without affecting its torque density. The best design with high performance is used for final current control optimization simulation. [ABSTRACT FROM AUTHOR]

Different MRAS based approaches are gaining ample importance for the speed estimation of AC machine drives because of their simplicity and direct physical interpretation. In this work, MRAS is introduced for the sensorless control of promising low-cost brushless doubly-fed reluctance motor drive under primary field orientation and maximum torque per inverter ampere (MTPIA) conditions. In this regard, secondary flux vectors are employed as the control quantity in the formulation of the proposed MRAS. All the analytical studies, in this context, are carried out in MATLAB/Simulink. The scheme is further validated by a real-time experimentation using dSPACE-1103 based brushless doubly-fed reluctance machine (BDFRM) prototype. The simulation study and test results confirm the robust performance of the proposed controller around the synchronous speed. The investigation decisively affirms the feasibility of MRAS based approach for sensorless speed control of BDFRM drive as well. [ABSTRACT FROM AUTHOR]

The accurate prediction of temperature rise in various parts of a machine plays a significant role in ensuring that the machine delivers the required performance avoiding failures that arise due to high temperatures. In this paper, a lumped parameter thermal model is presented for exterior-rotor axial flux switched reluctance motors. Depending on its geometry, each part of the motor is modeled as a thermal equivalent circuit based on general cylindrical or cuboidal components. A total thermal network is obtained by proper connection of these sub-circuits. The model was calibrated by a stationary test; then, running conditions were applied to the model. The sensitivity of the model to the heat transfer coefficients was investigated by considering the effect of the coefficient variation on the estimated steady-state temperatures. Results show that the winding temperature, as the hottest part of the motor, is the most sensitive to the frame-to-ambient heat transfer coefficients. [ABSTRACT FROM AUTHOR]

In the new generation of “Stop & Start” starters, a DC series motor with high power density is used. In this application, non-symmetrical machines are used due to the single wave winding in brushed motors. The saturation of the iron core in this application reaches a really high level. Moreover, armature reaction in DC machine with a large stator pole spans makes this phenomenon even more enhanced. All these criteria lead to model the whole machine in highly saturated conditions which is time consuming. In this paper, a fast reluctance network (RN) model for an equivalent machine is proposed. It takes into account the armature reaction in high saturation conditions. It also allows a good accuracy and permits us to show the relevance of taking into account this phenomenon in torque calculation. This model is validated by a finite element (FE) method in many operating points, and by a statistical approach. It shows high robustness and low computation time. Finally, an optimization procedure using this reluctance network model and FE is presented in order to show the accuracy of the RN compared to FE model. [ABSTRACT FROM PUBLISHER]

This paper presents an application of direct torque and flux control (DTFC) for a four-switch three-phase inverter (FSTPI)-fed synchronous reluctance motor (SynRM) in which the saturation and iron losses' effects are involved in the machine control modeling. The DTFC switching technique for the SynRM fed by FSTPI in low-power and low-cost applications is implemented by imitating the six-switch three-phase inverter (SSTPI). By considering equal effective vectors depicted in SSTPI, theαβstationary reference frame is represented by using six sectors. Similarly, the voltage space vector formation is constructed in FSTPI. Accordingly the SynRM performance under DTFC is precisely analyzed by considering the saturation and iron losses' effects. The DTFC behavior based on SSTPI- and FSTPI-fed SynRM is evaluated using Simulink benchmark. At different operating conditions, further simulation and experimental results of DTFC based on FSTPI dynamically confirm the effectiveness of the proposed control application on the SynRM. [ABSTRACT FROM PUBLISHER]

Torque ripple is a major problem for switched reluctance motors, which may cause undesirable vibration and acoustic noise, especially at low speed. This paper presents an optimal topology structure of rotor for 8/6 pole switched reluctance motor by using the level set method. The nonlinear ferromagnetic material boundary of rotor pole is implicitly represented through an embedded level set function. This method is applied to obtaining the optimal distributions of material in the design domain for minimizing torque ripple and maximizing average torque. In the optimization objective function, the reluctivity of ferromagnetic material is selected as the design variable. The normal velocity is derived from sensitivity analysis, where the adjoint variable method is utilized. Two-dimensional finite element method is employed to calculate the electromagnetic parameters of this electric machine. Analysis results obtained from the transient simulation of electromagnetic field coupled with control circuit show that the torque ripple is reduced effectively by using the optimized rotor structure. [ABSTRACT FROM AUTHOR]

Based on a mapping (2013) of citizen initiatives in 17 European countries, this article explores the diversity in which governments recognise, respond to and engage with such citizen initiatives, mainly through legal definitions, funding schemes, and support practices. In many cases, governmental policies consider citizen initiatives as vehicles of public support for international development and as an addition to the already plural field of development actors. Contrastingly, available subsidies and support programmes are mainly tailored towards increasing professionalism, aiming to impose a minimum of quality standards on projects deployed. Evidence from the mapping also shows that, recently, central governments have gradually withdrawn from existing funding programmes, leaving the dealings with citizen initiates to local levels (region, province or municipality). Depending on how citizen initiatives are perceived – vehicles of public support, a welcome addition to the plural field of development actors, or initiatives that simply make a difference on the ground – the question arises whether that disconnect from central government should be considered worrying or welcoming. [ABSTRACT FROM AUTHOR]

Double-rotor switched reluctance machine (DRSRM) integrates two switched reluctance machines (SRMs) into one housing, providing a compact solution for hybrid power trains so that one DRSRM can replace two electric machines. This paper presents a new DRSRM design in which the stator flux barriers are removed and the flux lines in the interior and exterior machines are more evenly distributed. The effects of stator flux barriers are investigated, the loss mechanism in the DRSRM is analyzed, and finally, various winding configurations are compared. It is concluded that flux lines are more evenly distributed in the stator, reducing iron saturation and losses, while the interior and exterior machines can be independently controlled without sacrificing performance. Moreover, winding polarity in DRSRM is critical to reduce stator iron saturation and thereby losses. [ABSTRACT FROM PUBLISHER]

The rotor radial force is changed by adjusting the windings current value to control rotor suspension for various kinds of bearingless switched reluctance motor (BSRM). To accomplish the BSRM's suspension control, the radial force analytical model is necessary. Currently the mathematic relationship among radial force, winding currents, and rotor rotation angle has been built for double-winding BSRM, but the rotor eccentricity displacement has not been considered. That is, the existing radial force analytical model only can be used to analyze rotor radial force when rotor shaft is located in the central position. Actually, the rotor radial force is significantly affected by the rotor shaft eccentricity displacement. It is difficult for the bearingless motor to keep the rotor shaft staying in the central position, and the rotor shaft always runs around the central position with an eccentricity displacement. The rotor eccentricity caused by the radial force is considered in the paper to obtain the air-gap permeance and the windings inductances. Furthermore, the radial forces analytical model considering the rotor eccentricity displacement is derived. Finally, the finite-element method (FEM)-based results are applied and the dynamics simulation using the proposed model is accomplished to verify the correctness of the model. [ABSTRACT FROM AUTHOR]

The single-winding bearingless switched reluctance motor has a simple structure of windings in which the winding current produces the magnetic torque and levitation forces simultaneously. In the proposed control strategy, the average torque and average levitation force are regulated simultaneously to ease the current calculation and reduce the processing time of the digital signal processor. Moreover, to simplify the algorithm and investigate the relationship between the two kinds of bearingless switched reluctance motors, the equivalent transformation between single-winding and dual-winding bearingless switched reluctance motors is developed. After that, the average levitation-force control strategy is developed to regulate the torque and the radial force simultaneously. Accordingly, the system control block is established to achieve the closed-loop control, and experimental results verify that the proposed control strategy is effective for a stable levitation. [ABSTRACT FROM AUTHOR]

A variable structure robust position controller is presented for a three-phase synchronous reluctance motor. Linear control and variable structure control and pulse-width modulation generation are combined. These provide robust, fast, and accurate position control without the penalty of high chattering. Schemes, including conventional sliding-mode control and the proposed scheme, are tested under parameter variations, and sudden perturbations are applied to the system at a specific time, then compared. This scheme uses both advantages of traditional variable structure control methods and linear methods. The disadvantages of each method, such as chattering and parameter sensitivity, are minimized. Results demonstrate that the proposed technique preserves the classical linear position control merits, while both the steady-state and transient behavior are significantly improved in terms of robustness, accuracy, and low ripple. The results also prove that the position reference command is perfectly tracked in spite of motor parameter uncertainties and load torque disturbance in control of the system that uses the new schemes. [ABSTRACT FROM AUTHOR]

Abstract—In this research, torque ripple is analyzed, considering both slot opening and distributed winding effects for a 4-pole 60-slot synchronous reluctance machine under healthy and eccentricity fault conditions. Mathematical-based models and numerical methods are used to study the behavior of the machine, especially when it is supplied with a voltage source. For this purpose, the parameters of the machine are computed in both healthy and eccentricity fault conditions using the winding function theory. This article proposes a method that deals with both dynamic and static eccentricity fault diagnosis using a vibration signature; consequently, the results demonstrate that the eccentricity fault has no significant effect on the machine's current signature. Moreover, unbalanced magnetic pull is computed considering eccentricity fault, and then mechanical instability is proven to occur under such circumstances. It should be noted that previous works were generally based on the finite-element method, and current sources were used as suppliers; in this article, a mathematical-based model is utilized and voltage sources are considered as suppliers, which are two main advantages of this article over previous ones. Verification carried out by simulation via the finite-element method supports the effectiveness of the model and control approach. [ABSTRACT FROM PUBLISHER]

In this paper, a switched reluctance motor (SRM) with amorphous cores was designed and assembled. Comparing with another SRM that was made of silicon steel (50DW360) cores, the experimental results show that the core loss of amorphous core is only 10% of the silicon steel core at 600 Hz and 0·5 T and the maximum value of phase inductance in amorphous prototype is lower than that of 50DW360 by 7%. The motor performance, including flux distribution, copper loss, iron loss and efficiency, was simulated and predicted by the finite element analysis (FEA) method using Infolytica software. The results show that the iron loss of SRM with amorphous cores can be reduced by 90% and efficiency can be improved by approximately 2%. [ABSTRACT FROM AUTHOR]

This article presents a reference adaptive Hermite fuzzy neural network controller for a synchronous reluctance motor. Although synchronous reluctance motors are mathematically and structurally simple, they perform poorly under dynamic modes of operation because certain parameters, such as the external load and non-linear friction, are difficult to control. The proposed adaptive Hermite fuzzy neural network controller overcomes this problem, as using the Hermite function instead of the conventional Gaussian function shortens the training time. Furthermore, the proposed adaptive Hermite fuzzy neural network controller uses an online self-tuning fuzzy neural network to estimate the system's lumped uncertainty. The estimation method involves a fuzzy controller with expert knowledge of the initial weight of the neural network. Finally, the Lyapunov stability theory and adaptive update law were applied to guarantee system convergence. In this article, the responsiveness of the adaptive Hermite fuzzy neural network controller and an adaptive reference sliding-mode controller is compared. The experimental results show that the adaptive Hermite fuzzy neural network controller markedly improved the system's lumped uncertainty and external load response. [ABSTRACT FROM PUBLISHER]

This article presents an exhaustive study about the influence of some design parameters, such as the number of phases, pole stroke, and current density, in the behavior of a linear switched reluctance motor. The linear switched reluctance motor's performance is assessed, taking into account a set of quality indices, which are the energy conversion loop quality factor, propulsion force per unit of primary steel volume, per unit of copper mass, per unit of air-gap surface, and force ripple factor. The study is carried out by means of two-dimensional finite-element analysis. Finally, the results are discussed, and as a consequence, a set of linear switched reluctance motor configurations with optimal performance according to the quality indices is defined. [ABSTRACT FROM PUBLISHER]