Search

We propose a 6-phase 12/10 switched reluctance motor (SRM) with a polygon connection. The transformation between star and polygon connections is not equivalent to that between star and delta connections of a conventional 3-phase motor. In this paper, the transformation between star and polygon connections is theoretically described. In addition, the current condition that maximizes torque is described. Finally, the torque of both connections is compared in terms of the AC-DC current ratio. [ABSTRACT FROM AUTHOR]

Summary: The reliability of power converters is crucial for achieving high‐performance operation in switched reluctance motor (SRM) systems. However, there is a notable deficiency in reliability‐oriented design of power converters that can effectively integrate both static and dynamic reliability indicators. To address this issue, this paper proposes a reliability design methodology for power converters based on the Lambert importance model, aimed at enhancing reliability of SRM systems. Firstly, the modeling principles of Lambert importance model are presented. Subsequently, a reliability design method is proposed to maximize reliability within a unit economic cost framework. Especially, the proposed design scheme is designed to maximize reliability enhancement potential through a two‐pronged approach: strategic topology selection informed by potential reliability assessments and component selection guided by importance calculations. Meanwhile, dynamic reliability evaluation is carried out to form a double‐loop reliability feedback and increase the credibility of design scheme. Finally, an example is developed to verify the validity of proposed reliability design scheme. [ABSTRACT FROM AUTHOR]

Due to the strong nonlinearity and large torque ripple of switched reluctance motor, a cascaded fractional order PID sliding mode control system is designed. Considering the difficulty of parameter adjustment caused by the complexity of the system, the optimization technology using dung beetle optimizer is introduced to optimize the designed cascaded controller and control the speed and torque ripple. To prove the effectiveness of the proposed cascaded controller, a control model is built in MATLAB/Simulink, and compared with whale optimization algorithm, particle swarm optimization, sparrow search algorithm to verify the response effect of the cascaded controller. A cascaded double PID controller is also built for comparison to verify the effectiveness of fractional order PID sliding mode controller. The results show that the cascaded fractional order PID sliding mode controller optimized by dung beetle optimizer is better than another cascaded double PID controller, produces the minimum torque ripple, and has better speed response and stability. The torque ripple of motor is suppressed. © 2024 Institute of Electrical Engineers of Japan and Wiley Periodicals LLC. [ABSTRACT FROM AUTHOR]

The benefits of utilizing Switched Reluctance Motor (SRM) drives in traction applications can be realized fully by improving the electromagnetic performance of the machine in the generating mode of operation. This is because the generating capability of an SRM drive could be utilized for regenerative braking and also for the machine to generate power for the vehicle while the engine is in operation. In this paper, a current profiling-based control strategy is proposed to reduce the torque ripple in an SRM drive in the generating mode. The reference current profile is determined using a multi-step computation method to minimize torque ripple and maximize the average torque. The reference current profile is derived based on the reference torque command by utilizing the torque–current–angle look up table. The flux linkage characteristics of the SRM are considered when deriving the phase reference current profile. Then, the performance of the proposed profiling method, analytical linear and cubic torque sharing functions (TSFs), and the average torque optimization scheme are compared using simulation results. Finally, an experimental correlation is performed to validate the efficacy of the proposed control scheme. [ABSTRACT FROM AUTHOR]

In view of the disadvantages of negative torque and low operation efficiency in the traditional direct torque control (DTC) for the switched reluctance motor drive (SRD), a novel DTC strategy based on optimal turn-on angle is proposed in this paper. First, the flux hysteresis controller of the traditional DTC is cancelled and the SRM is only controlled by the torque hysteresis controller. The actual rotor position angle is used to divide the sectors instead of the angle calculated by the stator flux, which does not need to select the optimal given flux value, and makes the division of sectors more in line with the inductance characteristics of the SRM. Second, the function for calculating the optimal turn-on angle is designed and the sectors are reallocated. The optimal voltage vector is selected according to the output signal of the torque hysteresis controller and sector position. Finally, the 12-sector DTC method is selected as comparison algorithm and the correctness of the proposed method is confirmed by simulation and experimental results. It is demonstrated that the proposed strategy retains the advantages of the simple structure of the traditional DTC. In addition, it eliminates negative torque, improves the DC bus voltage utilization and torque ampere ratio, and reduces the torque ripple, switching frequency and copper losses. [ABSTRACT FROM AUTHOR]

This paper presents a thermal analysis of a switched reluctance machine (SRM) with a 6/4 pole topology. Employing a two-dimensional thermal finite element model in Maxwell 2D integrated into a lumped parameter thermal network in MotorCAD, the research aims to realize critical temperature points within the SRM, focusing on the windings and laminations to identify potential hotspots. To ensure continuous operation without compromising structural integrity, temperature constraints of 150 °C for the windings and 100 °C for the laminations were enforced. The investigation extends to the cooling domain by utilizing a housing cooling jacket and ethylene glycol and water ratio (EGW) of 60/40 as the cooling fluid. An exploration of various volume flow rates revealed that 15 l/min was the optimal choice, resulting in the lowest temperatures observed in both the winding and lamination regions. This study emphasizes the shift of hotspot temperatures from the stator winding in the low-speed region to the rotor in the high-speed range, impacting the overall continuous operating time. This holistic examination significantly contributes to a broader understanding of electric machine thermal management and offers invaluable insights for practical applications in electric vehicles, manufacturing processes, and various industrial settings. [ABSTRACT FROM AUTHOR]

During the driving process of the in-wheel drive electric vehicle, the air gap eccentricity of the motor caused by external disturbance cannot be avoided, resulting in a negative effect on vehicle dynamics. In this paper, the negative effect of vehicle lateral dynamics caused by motor-inclined eccentricity and the corresponding control method are studied. According to the Maxwell stress tensor and the air gap permeance correction coefficient, the unbalanced radial force under the inclined eccentricity of the in-wheel motor is characterized, and the corresponding vehicle dynamics model is established. Based on the vehicle dynamics model, different steering conditions are set to explore the influence of inclined eccentricity on the negative effect of vehicle lateral dynamics. It is found that the inclined eccentricity affects the handling stability of the vehicle under normal conditions and affects the rollover stability under extreme conditions. In order to solve these problems, the integrated control strategy is formulated by using the steering and driving system of an electric vehicle, and the particle swarm optimization algorithm is introduced to optimize it. The simulation results show that the proposed integrated optimal control of active rear-wheel steering and direct yaw control can effectively alleviate the negative effect of vehicle lateral dynamics caused by the inclined eccentricity of the in-wheel motor under different working conditions. [ABSTRACT FROM AUTHOR]

Currently, switched reluctance motors are considered the most promising type of electromechanical energy converter without permanent magnets, especially for operations at sub-nominal speeds. To control of a switched reluctance motor to minimize torque ripple requires the regulation of phase currents based on the rotor angular position, utilizing the flux linkage as a function of both current and rotor angle. The flux linkage characteristic is essential in control systems that indirectly determine the rotor position. The paper presents an experimental methodology for deriving the flux linkage characteristic of a switched reluctance motor. The calculation of flux linkage for each rotor position angle of the electric machine is provided. The proposed methodology involves mechanically locking the rotor and periodically applying voltage to one of the motor phases using a power converter to gather data on phase current and voltage. Using the proposed experimental methodology, the relationships between flux linkage, phase current, and rotor angle were obtained. The results demonstrate that this methodology can be effectively utilized to accurately determine the flux linkage characteristic of a switched reluctance motor. The experimental methodology proposed in this paper can be employed to generate the flux linkage characteristic of a switched reluctance motor. This approach is particularly advantageous for designing model predictive control systems.

Switched reluctance Motor (SRM) drives provide several advantages over other electric drive systems, making them one of the finest options for EV applications. Its excellent qualities are the robust design, double saliency, fault tolerance, and ability to withstand the heat of SRM drives. In this article, a SRM powered by 18,650 Li-ion battery modules with the purpose of optimising their performance is addressed. In order to minimise torque ripple (Tr) and provide an exact speed response in SRM, this article mainly presents a speed controller (Nc) and current controller (Ic) technique. The accurate speed control and torque ripple (Tr) reduction of a SRM is controlled using the particle swarm optimisationoptimisation technique (PSO) with speed and current control mechanisms. The FOPID Nc in the outer loop and Ic in the inner loop, respectively, are regulated, as are the 3-∅, 6/4 SRM turn-on (${T_O}$ T O ), and turn-off (${T_F}$ T F ), angles. The torque ripple (Tr) coefficient and fitness function (FF) of the PSO algorithm are observed to be lower when compared to other optimisation methods found in past studies. These results were compared with existing optimisation methods, such as the SHO, LUS, GA, and Ant-Lion algorithms, show that a cascaded fractional order PID(FOPID) controller offers better speed, current, and torque responses, as well as smaller current and torque ripples, under numerous different load and speed conditions. Under all load conditions, it has been demonstrated that the PSO-FOPID controller has the best speed response and minimal torque ripples when compared with other optimisation techniques. Based on the research results, it is possible to conclude that PSO-FOPID-based speed controllers increase SRM drive performance by minimising torque ripple, lower rise time, and settling time due to their high exploitation capacity. [ABSTRACT FROM AUTHOR]

Abstract The magnet-less switched reluctance motor (SRM) speed-torque characteristics are ideally suited for traction motor drive characteristics and its advantage to minimize the overall cost of on-road EVs. The main drawbacks are torque and flux ripple, which have produced high in low-speed operation. However, the emerging direct torque control (DTC) operated magnitude flux and torque estimation with voltage vectors (VVs) gives high torque ripples due to the selection of effective switching states and sector partition accuracy. On the other hand, the existing model predictive control (MPC) with multiple objective and optimization weighting factors produces high torque ripples due to the system dynamics and constraints. Therefore, existing DTC and MPC can result in high torque ripples. This paper proposed a finite set (FS)-MPC with a single cost function objective without weighting factor: the predicted torque considered to evaluate VVs to minimize the ripples further. The selected optimal VV minimizes the SRM drive torque and flux ripples in steady and dynamic state behaviour. The classical DTC and proposed model were developed, and simulation results were verified using MATLAB/Simulink. The proposed model operated in SRM drives experimental results to prove the effective minimization of torque and flux ripples compared to the existing DTC.

Electric vehicles have seen substantial growth in recent years in the emerging economies of the world. The current market scenario of E-vehicles is dominated by PMSM or BLDC motors due to their higher torque-to-power density, and efficiency with added performance metrics of the motor. However, the higher capital cost of permanent magnets makes the motor designers to consider an alternative to magnetic motors, the so-called Switched Reluctance Motors (SRM). With proper FEM analysis and controller design, if SRMs can able to achieve the performance metrics of a PMSM/BLDC, it will be a breakthrough in the automotive sector with affordable prices. Based on the aforementioned facts, this research work focuses on SRM as a viable alternative to the existing PMSM/BLDC motor. The work concentrates on the design and development of an 8/6 SRM for a Tri-wheeler E-vehicle application. The designed motor is fabricated, tested and controlled by WAVECT, an FPGA-based real-time digital controller which is used to control the commutation of the 8/6 SRM. The yielded response satisfactorily proves that the designed 8/6 SRM can be effectively used for the Tri-wheeler E-vehicle application, thereby paving the way for sustainable energy conservation in the automotive sector.

This paper presents the design and analysis of two distinctive three-phase permanent magnet-embedded switched reluctance motors for electric three wheelers. The configurations used in this work are a 12/8 classic SRM and a 12/10 E-core stator SRM. For the configuration of the 12/10 E-core stator, horizontal alignment of the permanent magnets is introduced, and the magnets are placed on the stator auxiliary poles. In the case of 12/8 SRM, the permanent magnet is placed in the stator yoke. Initially, a dynamic calculation of the vehicle and the SRM design process are carried out to determine the power rating and the optimal design parameters. The motor performance analysis is carried out using finite element-based software with the acquired specifications. The comparative analysis is established by employing various magnet materials with the intention of achieving the same motor torque. Outcomes reveal that the configuration of the permanent magnet embedded in the 12/10 E-core stator SRM is able to generate the needed average torque with minimal cogging torque and torque ripple using low-cost ferrite magnets, making it suitable for electric three-wheeler applications. [ABSTRACT FROM AUTHOR]

Electric vehicles have seen substantial growth in recent years in the emerging economies of the world. The current market scenario of E-vehicles is dominated by PMSM or BLDC motors due to their higher torque-to-power density, and efficiency with added performance metrics of the motor. However, the higher capital cost of permanent magnets makes the motor designers to consider an alternative to magnetic motors, the so-called Switched Reluctance Motors (SRM). With proper FEM analysis and controller design, if SRMs can able to achieve the performance metrics of a PMSM/BLDC, it will be a breakthrough in the automotive sector with affordable prices. Based on the aforementioned facts, this research work focuses on SRM as a viable alternative to the existing PMSM/BLDC motor. The work concentrates on the design and development of an 8/6 SRM for a Tri-wheeler E-vehicle application. The designed motor is fabricated, tested and controlled by WAVECT, an FPGA-based real-time digital controller which is used to control the commutation of the 8/6 SRM. The yielded response satisfactorily proves that the designed 8/6 SRM can be effectively used for the Tri-wheeler E-vehicle application, thereby paving the way for sustainable energy conservation in the automotive sector. [ABSTRACT FROM AUTHOR]

The magnet-less switched reluctance motor (SRM) speed-torque characteristics are ideally suited for traction motor drive characteristics and its advantage to minimize the overall cost of on-road EVs. The main drawbacks are torque and flux ripple, which have produced high in low-speed operation. However, the emerging direct torque control (DTC) operated magnitude flux and torque estimation with voltage vectors (VVs) gives high torque ripples due to the selection of effective switching states and sector partition accuracy. On the other hand, the existing model predictive control (MPC) with multiple objective and optimization weighting factors produces high torque ripples due to the system dynamics and constraints. Therefore, existing DTC and MPC can result in high torque ripples. This paper proposed a finite set (FS)-MPC with a single cost function objective without weighting factor: the predicted torque considered to evaluate VVs to minimize the ripples further. The selected optimal VV minimizes the SRM drive torque and flux ripples in steady and dynamic state behaviour. The classical DTC and proposed model were developed, and simulation results were verified using MATLAB/Simulink. The proposed model operated in SRM drives experimental results to prove the effective minimization of torque and flux ripples compared to the existing DTC. [ABSTRACT FROM AUTHOR]

The switched reluctance motor (SRM) has many merits, such as robustness, a simple construction, low cost, and no permanent magnets. However, its deployment in servo applications is restrained due to acoustic noise and torque ripple (TR). This paper presents a new torque control approach for TR reduction in switched reluctance drives. The approach is based on the maximum utilisation of the available dc-link voltage, hence extending the zero torque-ripple speed range. The approach is suitable for an SRM with any number of phases and stator/rotor poles. Soft switching control is deployed, which reduces switching losses. At any instant (regardless of the number of phases being conducted simultaneously), only one phase current is controlled. The well-established torque-sharing function concept is adapted and generalised to cater for more than two phases conducting simultaneously. MATLAB/Simulink confirmation simulations are based on the widely studied four-phase 8/6, 4 kW, 1500 rpm SRM. [ABSTRACT FROM AUTHOR]

This paper presents a review of the most common power converters and torque ripple minimisation approaches for switched reluctance motors (SRMs). Unlike conventional three-phase AC motors, namely squirrel cage induction motors and permanent magnet synchronous motors, which require a typical three-phase inverter for operation, the switched reluctance motor requires a different topology power converter for reliable and efficient operation. In addition, due to the non-linear, discrete nature of SRM torque production, torque ripple is severely pronounced, which is undesirable in servo applications like electric vehicles. Hence, deploying a proper torque control function for smooth and quiet motor operation is crucial. This paper sheds light over the most popular SRM power converters as well as torque ripple minimisation methods, and it suggests an optimal SRM drive topology for EV applications. [ABSTRACT FROM AUTHOR]

Summary: The switched reluctance motor (SRM) is a prominent electrical machine drive with low cost and good performance in different drive applications. This machine's main drawbacks are torque ripple and flux ripple. However, the existing SRM‐operated direct torque control (DTC) Voltage vectors (VVs) give high torque ripples due to improper sector division and minimum selection of VVs switching states. On the other hand, a two‐level hysteresis torque band can result in torque ripples. Therefore, this paper proposed DTC using 16 partitions, active small and large VVs, and a multilevel hysteresis torque band (MHTB) strategy to mitigate the torque ripple further. More active VVs (i.e., 16) are employed in the modified sector‐based switching tables, suppressing the torque ripples. The proposed strategy is verified and validated using MATLAB/Simulink. The detailed result discusses the response of torque, flux, and speed of SRM. The DTC‐operated SRM drive experimental results prove the effective minimization of torque ripples in the proposed DTC compared to the existing DTC. [ABSTRACT FROM AUTHOR]

Copyright of Journal of Chongqing University of Technology (Natural Science) is the property of Chongqing University of Technology 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.)

In this paper, a new torque sharing function control strategy is proposed to reduce the torque ripple. The traditional torque ripple methods, such as exponential and linear torque allocation strategies, the torque generation capacity of each phase and the power limitation of the power converter is not taken into account, in this paper, the communication region is divided into three intervals by establishing a new partitioning standard. According to the re-established reference function of torque generation, the torque deviation caused by phase current tracking error is compensated according to the torque generation capacity. Both optimization of torque ripple suppression and copper loss minimization are taken into consideration in this paper. To verify the validity and performances of the proposed TSF methods, simulations and experiments have been implemented in a 12/8 structure Switched Reluctance Motor prototype. This method can be applied to other switched reluctance motors with different topologies. Result shows lower current tracking error and better performance of torque ripple minimization compared with the conventional two-interval compensation method. [ABSTRACT FROM AUTHOR]

Summary: Electric vehicles (EVs) have gained a forward approach for achieving the low carbon economy and green transportation. Switched reluctance (SR) motor‐based propulsion mechanisms have been popularly used for EVs due to the wide speed range capability. The conventional phase current regulation technique does not give the satisfactory reduction of torque ripple in SR motor drive, particularly for automotive applications. To overcome the issue, a frontend boost converter (FEBC) is proposed to realize the quick excitation and demagnetization. Initially, the problems associated with the conventional asymmetric half bridge converter are investigated at various levels of phase current. The various operating modes of proposed drive system with FEBC are explained in detail. The proposed FEBC has the significant benefit of being able to provide variable boosting voltages based on the dynamic behavior of the SR motor. The phase voltages are increased during the fast magnetization and demagnetization modes due to the inclusion of FEBC, and hence, quick magnetization and demagnetization have been achieved. The proposed FEBC drive system has been simulated through the Matlab Simulink toolbox. The experimental results are also carried out in order to validate the simulation results. [ABSTRACT FROM AUTHOR]

This paper proposes a multi-platform algorithm methodology in order to define firing angles of torque sharing functions (TSFs) for the indirect torque control of switched reluctance motors (SRM) through a hardware-in-the-loop (HIL) system. This proposal is used to achieve optimal levels of torque ripple and losses with accuracy and reliability, while taking advantage of real-time simulation. The analysis is performed assuming steady-state conditions of speed and torque reference for levels below the base speed, aiming to obtain firing angles ensuring optimal tracking performance. A novel methodology is proposed by using a grid search algorithm that handles the communication between Python, Code Composer, and the Typhoon HIL device. For that, an experimental data FPGA-based model with 500~ns of simulation time step is used to ensure highly accurate dynamic responses of current and electromagnetic torque. Moreover, controller-HIL (C-HIL) is used to have a safe and high fidelity testing environment, allowing rapid testing before transitioning to an experimental test bench. The simulation results are experimentally validated, demonstrating that the proposed strategy is effective and ensures optimal performance, taking into account peripheral systems of A/D, signal conditioning, PWM, and sensor emulation.

As electric vehicles (EVs) continue to acquire prominence in the transportation industry, improving the outcomes and efficiency of their propulsion systems is becoming increasingly critical. Switched Reluctance Motors (SRMs) have become a compelling option for EV applications due to their simplicity, magnet-free design, robustness, and cost-effectiveness, making them an attractive choice for the growing EV market. Despite all these features and compared to other electrical machines, SRMs suffer from some restrictions, such as torque ripple and audible noise generation, stemming from their markedly nonlinear characteristics, which affect their productivity and efficiency. Therefore, to address these problems, especially the torque ripple, it is crucial and challenging to enhance the performance of the SRM drive system. This paper proposed a comprehensive review of torque ripple minimization strategies of SRMs in EV applications. It covered a detailed overview and categorized and compared many strategies, including two general categories of torque ripple mitigation encompassing optimization design topologies and control strategy developments. Then, focused on control strategy improvements and divided them into torque and current control strategies, including the sub-sections. In addition, the research also provided an overview of SRM fundamental operations, converter topologies, and excitation angle approaches. Last, a comparison between each method in torque control and current control strategies was listed, including the adopted method, features, and drawbacks.

High torque ripple limits the application area of the switched reluctance motor (SRM). To solve this problem, the sliding mode control algorithm is applied to the speed control in SRM. However, the uncertainty of motor parameters significantly impacts the electromagnetic torque of SRM. Therefore, a neural network sliding mode controller (NNSMC) based on parameter online learning is designed in this paper. The internal parameters of SRM are learned online through speed error, resulting in the combined control of the neural network and sliding mode. The Lyapunov stability method is used to prove the stability of the algorithm. The simulation results show that the proposed method can effectively learn the parameters of SRM, reduce torque ripple and improve the operational performance of the motor.

AbstractCore loss estimation in switched reluctance motor is a complex task, due to non-linear phenomena and non-sinusoidal flux density waveforms. Several methods have been developed for estimating it (e.g. empirical, and physical-mathematic models), each one with merits and limitations. This paper proposes a new method for core losses estimation based on Finite Element Method Magnetics software. The main idea is using the machine phase-current harmonics as input for estimating core losses. In addition, a comparative study is carried out, where the proposed approach is faced up to a different one, based on Fourier decomposition of the flux density waveforms in the machine sections. In order to systematically analyze and compare the applied estimation cores loss techniques, a case study of a three-phase 6/4 SRM for different simulation scenarios is introduced. The outcomes of both methods are discussed and compared, where core loss convergence is found for limited speed and load ranges.

Copyright of Journal of Chongqing University of Technology (Natural Science) is the property of Chongqing University of Technology 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 switched reluctance motor (SRM) is an electric motor that can function effectively in challenging operating conditions thanks to its sturdy construction and resilience to external factors. Despite somewhat weaker parameters in terms of energy and power density compared to other types of electric motors, the SRM is recommended for applications such as the military, mining, industry, and other locations where the reliability of vehicle drive is essential. Therefore, monitoring the motor's operating state and identifying the fault's condition while it is still in the beginning phase is crucial. The paper presents SRM diagnostic methods and the authors' research on the test stand. The examined faults were dynamic eccentricity and imbalance. Experiments were performed for various rotational speeds and loads. The analysis of the results consisted of the interpretation of the current and acceleration spectra acquired from proper sensors. The spectra bands are compared in terms of their amplitudes and frequency values. These results show the nonlinear characteristics of the motor's operation, and interpretation of these results allows for estimating the impact of a fault parameter on a motor's performance. [ABSTRACT FROM AUTHOR]

In order to solve the problem that Switched Reluctance Motor (SRM) generates torque pulsation phenomenon during operation, which reduces the stability of loom spindle operation, this paper proposes and designs a multi-algorithm fusion-based SRM control strategy from the point of view of control strategy research. Combined with the operating characteristics of the loom, the causes of SRM torque pulsation are analyzed from the point of view of SRM control strategy, and combined with the spindle control indexes, the voltage chopper control and torque distribution function are introduced to construct the SRM control strategy scheme for the loom. On this basis, an optimization strategy based on the fusion of fuzzy control algorithm, particle swarm algorithm and simulated annealing algorithm is proposed to optimize the torque distribution function, and the algorithmic process of SRM control strategy is verified through comparative tests. The results show that the control strategy can make its torque pulsation reduced to less than 10%, the speed rise time is less than 0.1 s, and the relative error of the speed is less than 0.05%, which meets the index requirements of the spindle drive. This proves that the SRM torque pulsation can be reduced by the multi-algorithm fusion control strategy without increasing the hardware cost, which provides a useful reference for solving the SRM torque pulsation problem under the requirement of low cost. [ABSTRACT FROM AUTHOR]

Copyright of Electric Machines & Control / Dianji Yu Kongzhi Xuebao is the property of Electric Machines & Control 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.)

In the traditional control scheme of a 12/8-pole bearingless switched reluctance motor (BSRM), radial force and torque are usually controlled as a compromise due to the conflict between their effective output areas. Additionally, each phase requires individual power circuits and is excited in turn to produce a continuous levitation force, resulting in high power device requirements and high controller costs. This paper discusses a 12/8-pole single-winding hybrid-rotor bearingless switched reluctance motor (HBSRM) with a hybrid rotor consisting of cylindrical and salient-pole lamination segments. The asymmetric rotor of the HBSRM slightly increases the complexity of its structure and magnetic circuit, but makes it possible to generate the desired radial force at any rotor angular position. A control scheme for the HBSRM is developed to utilize the independent excitation of the four windings in one phase to generate the desired levitation force at any rotor angular position, and it requires only half the number of power circuits used in the conventional control scheme of a 12/8-pole single-winding BSRM. Different from the average torque chosen to be controlled in traditional methods, this scheme directly regulates the instantaneous total torque produced by all excited phases together and presents a current algorithm to optimize the torque contribution of each phase so as to reduce torque pulsation, and the improved performance of this bearingless motor is finally validated by simulation analysis. [ABSTRACT FROM AUTHOR]

Given the high saturation, strong nonlinearity, and tight coupling characteristics of the magnetic paths in a switched reluctance motor (SRM), accurately modeling flux-linkage is challenging, thus leading to excessive torque ripple during SRM torque control. In order to enhance the precision of the SRM flux-linkage model, a neural network-based method for the parameter identification of SRM's nonlinear flux-linkage model was proposed in this study. Logistic mapping elements were incorporated into the feedback layer of the diagonal recurrent neural network (DRNN), and chaotic control parameters were designed. Then, the construction of an analytical model of the nonlinear exponential flux-linkage function using the chaotic diagonal recurrent neural network (CDRNN) was established. By utilizing sample data of flux-linkage, current, and angular position, the parameters of this model were estimated, thus achieving a precise nonlinear exponential function model of the flux-linkage. Results show that, the integration of logistic mapping in the CDRNN feedback layer effectively prevents the local minima typically associated with conventional DRNN. The maximum error in the identified flux-linkage is less than 0.01 Wb, and the accuracy reached 95%. Compared with the DRNN method, the CDRNN approach demonstrates significantly reduced errors and higher model precision. This study offers valuable insights for enhancing the performance of SRM torque ripple control. [ABSTRACT FROM AUTHOR]

Switched reluctance motors (SMRs) are competitors of traditional ones in electric vehicles due to their high specific performance and the absence of permanent magnets and windings in the rotor design, which increases reliability and reduces production costs. Due to the pronounced nonlinearity of their magnetic characteristics and discreteness in control, SRMs are characterized by significant torque ripples, noise, and vibrations, to suppress which it is advisable to use direct instantaneous torque control (DITC), which is widely used in traditional electric drives. However, SRMs differ from traditional motors, so known technical solutions cannot be applied to them. Simulation modeling is a convenient and universal tool for research and development of methods and algorithms for SRM control, and the MATLAB/Simulink environment makes it possible to successfully implement them. The article considers two of the best-known and fundamentally different DITC options with respect to a four-phase SRM. Their shortcomings are substantiated and illustrated, and a new DITC option is proposed that is most suitable for controlling an SRM as part of a traction electric drive of electric vehicles. [ABSTRACT FROM AUTHOR]

Purpose: The present work investigates the influence of different laminating materials on structural and vibration characteristics of 6/5 modified segmented rotor switched reluctance motor (MSRSRM) for cooling fans in automobile applications. Methods: Different laminating silicon steel materials like M890-50d, M43, and M19 are taken into consideration, and electromagnetic, structural, modal, and harmonic analyses were carried out over the proposed 6/5 MSRSRM to identify the influence of these laminating materials. In this regard, the 3D-finite element model (FEM) of the 6/5 MSRSRM is created. The electromagnetic analysis is carried out using the FEM software package SIMCENTER MAGNET and performance parameters like average torque, torque ripple, and electrical losses are determined. The structural, modal, and harmonic analyses were carried out using the ANSYS software package, and the 6/5 MSRSRM rotor's maximum deflection, maximum stress, and modal frequencies were identified. Results: The results revealed that the 6/5 MSRSRM with M19 laminating material resulted in less maximum deflection of 0.00186 mm, stress of 1.3032 MPa, and high natural frequency of 3750 Hz, which resulted in structurally more stable and less acoustic 6/5 MSRSRM with least vibration effects. Conclusion: When compared to other laminating materials like M890-50d and M43, M19 laminating silicon steel material exhibits good performance in terms of its electromagnetic and vibrational characteristics. [ABSTRACT FROM AUTHOR]

The aim of this study is to investigate and determine the effect of accounting for the non-uniform distribution of magnetic induction (by detailing the stator tooth model) on the calculation results of magnetic losses in the stator teeth of a switched reluctance motor in quasi-steady-state modes. To achieve this goal, dependencies of phase flux linkage, electromagnetic torque of the motor, and additionally, dependencies of the root mean square values of magnetic inductions in stator tooth elements on the rotor angle and current have been determined using the finite element method. An investigation of dynamic modes of the switched reluctance motor based on an improved simulation model has been conducted at various values of constant load torque. Dependencies of magnetic inductions over time for each stator tooth element for the studied quasi-steady-state operating modes have been obtained. Magnetic losses have been calculated, taking into account the maxima of the temporal dependencies of root mean square values of magnetic induction in stator tooth elements. The most important outcome is a quantitative assessment of the influence of the non-uniform distribution of magnetic induction on the calculated value of magnetic losses based on the detailing of the stator tooth model in the operational modes of the switched reluctance motor compared to the traditional approach. The significance of the work lies in developing an approach to refining the calculation of magnetic losses by considering local saturation in the magnetic circuit during the operation of the switched reluctance motor.

Because of their attractive features, switched reluctance motors (SRMs) are strong candidates with real chances on the market for several industrial applications including vehicle propulsion. However, the SRMs suffer from torque ripple and associated acoustic noise. A proper control algorithm can handle torque ripples to an accepted limit. However, the internal faults in stator windings of SRMs deteriorate not only the performance of control algorithm but also the output power, efficiency, and noise (torque ripple). They cause fast degradation of motor lifetime. Therefore, this paper introduces a novel method to counteract the internal faults in winding of SRMs. A new simulation method for SRMs including the capability of interturn faults is introduced. The proposed novel interturn fault tolerant control (FTC) is achieved based on average torque control (ATC) algorithm. The switching angles are optimized smartly providing a less complicated control algorithm to fit properly with the industrial platforms. The simplicity of overall control algorithm is still functional. The performance of proposed FTC is evaluated compared to healthy motor conditions as well as faulty conditions. The results show the superior performance of the proposed control.

The demand for electrical machines has been spurred by rising fuel costs, technological advancements, and urbanization. Consequently, there is an increased focus on developing machines with greater power density, improved efficiency, and enhanced vibroacoustic characteristics while promoting a more sustainable supply chain. This paper offers a thorough comparison of three distinct motor topologies: switched reluctance motor (SRM), interior permanent magnet synchronous motor (IPMSM), and induction motor (IM). The study begins with electromagnetic analysis of the motors, covering torque, output power, losses, and efficiency calculations. Subsequently, the investigation delves into radial force density waveforms, extracting the dominant radial force density harmonics and presenting patterns for each motor’s dominant radial force harmonics. Following this, a 3D assembly of the motors is introduced for modal analysis, determining their mode shapes and natural frequencies. Finally, vibroacoustic analysis is conducted for the proposed motors, with observed differences being discussed. These analyses are conducted solely for the rated operating point, as transitioning to other operating points does not alter the pattern of radial force harmonics or the correlation between acoustic noise and radial force harmonics.

Switched reluctance motor (SRM) usually adopts Direct Instantaneous Torque Control (DITC) to suppress torque ripple. However, due to the fixed turn-on angle and the control mode of the two-phase exchange region, the conventional DITC control method has low adaptability in different working conditions, which will lead to large torque ripple. For this problem, an improved DITC control method based on turn-on angle optimization is proposed in this paper. Firstly, the improved BP neural network is used to construct a nonlinear torque model, so that the torque can be accurately fed back in real time. Secondly, the turn-on angle optimization algorithm based on improved GRNN neural network is established, so that the turn-on angle can be adjusted adaptively online. Then, according to the magnitude of inductance change rate, the two-phase exchange region is divided into two regions, and the phase with larger inductance change rate and current is selected to provide torque in the sub- regions. Finally, taking a 3-phase 6/20 SRM as example, simulation and experimental verification are carried out to verify the effectiveness of this method.

Achieving increased fault tolerance in an electric motor requires decisions to be made about the type and specifications of the motor machine and its appropriate design. Depending on the type of motor, there are generally three ways to achieve an increased resistance of the drive system to tolerate resulting faults. The simplest way is to select the right motor and design it appropriately. Switched reluctance motors (SRMs) have a high tolerance for internal faults (in the motor windings). Failure tolerance can be improved by using parallel paths. The SRM 24/16 solution has been proposed, which allows for operation with four parallel paths. In this paper, a mathematical model designed to analyse the problem under consideration is provided. Based on numerical calculations, the influence of typical faults (open and partial short circuit in one of the paths) on the electromagnetic torque generated as well as its ripple and (source and phase) currents were determined. The higher harmonics of the source current (diagnostic signal) were determined. Laboratory tests were performed to verify the various configurations for the symmetric and emergency operating states. The feasibility of SRM correct operation monitoring was determined from an FFT analysis of the source current.

This paper presents a solution to reduce source current ripple in the electrical power supplying a switched reluctance motor (SRM) drive. Source current ripple negatively affects the power source by introducing a variable frequency component and increasing losses in the power source. Reducing the source current ripple is important, especially in battery electric vehicles (BEVs). The solution proposed in this paper for reducing source current ripple is to use a classic DC/DC boost converter connected in series with the SRM power supply system. The key to reducing source current ripple is the DC/DC converter control method proposed and described in this article. This method involves controlling the DC/DC converter synchronized with the speed of the SRM motor DC/DC. To verify the correct operation of the proposed solution, simulation and laboratory tests of an SRM drive were performed, the results of which are shown in this paper.

This paper discusses a numerical model for determining the radial electromagnetic force of switched reluctance motors under air gap eccentricity (vertical and tilt eccentricities). The authors compare experimental and simulation results to demonstrate that the proposed model can accurately simulate the behavior of radial forces in switched reluctance motors under various types of air gap eccentricity. Moreover, the paper attempts to establish a dynamic model of the SRM and nalyze the performance of the radial electromagnetic force under air gap eccentricity in typical scenarios.

The benefits of utilizing Switched Reluctance Motor (SRM) drives in traction applications can be realized fully by improving the electromagnetic performance of the machine in the generating mode of operation. This is because the generating capability of an SRM drive could be utilized for regenerative braking and also for the machine to generate power for the vehicle while the engine is in operation. In this paper, a current profiling-based control strategy is proposed to reduce the torque ripple in an SRM drive in the generating mode. The reference current profile is determined using a multi-step computation method to minimize torque ripple and maximize the average torque. The reference current profile is derived based on the reference torque command by utilizing the torque–current–angle look up table. The flux linkage characteristics of the SRM are considered when deriving the phase reference current profile. Then, the performance of the proposed profiling method, analytical linear and cubic torque sharing functions (TSFs), and the average torque optimization scheme are compared using simulation results. Finally, an experimental correlation is performed to validate the efficacy of the proposed control scheme.

High-speed motors are essential for accomplishing the reduction in size of motors for electric vehicles (EVs). The Switched Reluctance Motor (SRM) is notable for its capacity in high-speed drives as a result of its uncomplicated and sturdy rotor configuration. Nevertheless, obstacles such as substantial vibration and acoustic noise, as well as the intricacy of traditional current excitation techniques, impede the development of an efficient torque controller. In order to tackle these problems, the use of vector control has been suggested for SRM drives. However, its utilization in the high-speed range has not been thoroughly investigated. This study examines the necessary driving conditions, such as switching frequency and bus voltage, for achieving effective functioning of a SRM in the high-speed range. The research shows that the suggested SRM may be efficiently operated utilizing fuzzy logicbased vector control in high-speed situations, resulting in decreased vibration levels. Fuzzy logic controllers (FLCs), renowned for their exceptional performance in intricate, non-linear, or ill-defined systems, are used to augment the control strategy. The controllers use fuzzy sets, facilitating a seamless shift from membership to non-membership, hence enhancing the overall performance of the system. The results emphasize the potential of using fuzzy logic-based vector control as a viable method to advance high-speed SRM technology in electric vehicle applications. This led to improved efficiency and decreased vibrations in electric propulsion systems. [ABSTRACT FROM AUTHOR]

Core loss estimation in switched reluctance motor is a complex task, due to non-linear phenomena and non-sinusoidal flux density waveforms. Several methods have been developed for estimating it (e.g. empirical, and physical-mathematic models), each one with merits and limitations. This paper proposes a new method for core losses estimation based on Finite Element Method Magnetics software. The main idea is using the machine phase-current harmonics as input for estimating core losses. In addition, a comparative study is carried out, where the proposed approach is faced up to a different one, based on Fourier decomposition of the flux density waveforms in the machine sections. In order to systematically analyze and compare the applied estimation cores loss techniques, a case study of a three-phase 6/4 SRM for different simulation scenarios is introduced. The outcomes of both methods are discussed and compared, where core loss convergence is found for limited speed and load ranges. [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]

As electric vehicles (EVs) continue to acquire prominence in the transportation industry, improving the outcomes and efficiency of their propulsion systems is becoming increasingly critical. Switched Reluctance Motors (SRMs) have become a compelling option for EV applications due to their simplicity, magnet-free design, robustness, and cost-effectiveness, making them an attractive choice for the growing EV market. Despite all these features and compared to other electrical machines, SRMs suffer from some restrictions, such as torque ripple and audible noise generation, stemming from their markedly nonlinear characteristics, which affect their productivity and efficiency. Therefore, to address these problems, especially the torque ripple, it is crucial and challenging to enhance the performance of the SRM drive system. This paper proposed a comprehensive review of torque ripple minimization strategies of SRMs in EV applications. It covered a detailed overview and categorized and compared many strategies, including two general categories of torque ripple mitigation encompassing optimization design topologies and control strategy developments. Then, focused on control strategy improvements and divided them into torque and current control strategies, including the sub-sections. In addition, the research also provided an overview of SRM fundamental operations, converter topologies, and excitation angle approaches. Last, a comparison between each method in torque control and current control strategies was listed, including the adopted method, features, and drawbacks. [ABSTRACT FROM AUTHOR]

The inductance model used in traditional sensorless control methods for switched reluctance machines (SRMs) exhibits high-order harmonics. The precision of the motor may be impacted by the buildup of rotor estimate errors caused by these harmonics. To address this issue, this paper proposes a novel method for SRMs that employs a hybrid algorithm combining an enhanced second-order generalized integrator (SOGI)-based frequency-locked loop (FLL) and an active disturbance rejection control (ADRC)-based phase-locked loop (PLL). This approach involves coordinate transformation and parameter identification to reconstruct the motor inductance model. Rotor position errors are calculated using the unsaturated inductance difference method. In order to enhance the accuracy of motor position estimation, a hybrid algorithm is employed to efficiently filter out harmonic errors and mitigate the tremor effect caused by the rotor position differential algorithm. This hybrid algorithm enables the estimate of the motor's speed and rotor position. A sensorless control simulation model was developed using a 12/8 pole SRM to assess the motor's performance under varying load conditions. Based on the results obtained, it is established that the application of this method can accurately estimate the rotor's position and rotational speed and thus improve the performance of position sensorless control. Ultimately, a prototype system for a switched reluctance motor was created, and the effectiveness and feasibility of the proposed control technique were confirmed through experimental validation. This presents an innovative approach to engineering practice. [ABSTRACT FROM AUTHOR]