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A novel asymmetric interior permanent magnet (AIPM) machine is proposed in this paper. The machine's rotor consists of asymmetric poles and auxiliary flux barriers. The torque ripple of the machine is weakened by the asymmetric design of the left and right sides of the magnetic poles. The magnetic‐field‐shifting (MFS) effect improves the electromagnetic torque after adding the auxiliary flux barrier to shift the magnetic axis. The influence of critical geometrical parameters on the electromagnetic performance of the machine is investigated under the condition that the stator and permanent magnet volume remain unchanged. The relevant geometrical parameters of the machine are optimized and designed through the improved Taguchi method. The performance of the AIPM machine and the conventional machine under no‐load and load conditions are further compared by simulation analysis with finite elements, verifying the increase in electromagnetic torque and the reduction in torque ripple. © 2024 Institute of Electrical Engineers of Japan and Wiley Periodicals LLC. [ABSTRACT FROM AUTHOR]

A hybrid ferrite‐Al‐Ni‐Co permanent magnet assisted synchronous reluctance motor (PMa‐SyRM) for an air‐conditioner compressor is proposed. Al‐Ni‐Co PMs have high residual flux density similar to rare‐earth PMs such as Nd‐Fe‐B and Sm‐Co. Therefore, the performance parameters of the PMa‐SyRM such as power factor, efficiency etc., with Al‐Ni‐Co PMs can be improved without significantly increasing the cost of the motor. However, Al‐Ni‐Co PMs have a steep IInd‐quadrant B‐H curve, and the challenge lies in addressing their demagnetisation issues. In the proposed hybrid PMa‐SyRM, the rotor geometry is suitably optimised for placing the Al‐Ni‐Co PMs in the centre flux barriers to address the demagnetisation issues. Further, an analytical magnetic circuit is presented to design the proposed PMa‐SyRM. Later, 2‐D finite element analysis of the proposed motor including the demagnetisation analysis of PMs and stress analysis of the rotor is carried out and presented. A prototype is fabricated, experimental validation is carried out, and the results of the performance and cost are compared with that of ferrite and hybrid ferrite‐Nd‐Fe‐B PMa‐SyRM. [ABSTRACT FROM AUTHOR]

This paper presents a comprehensive analysis, electromagnetic evaluation, and prototyping of a novel motor structure called the sinusoidal rotor switched reluctance motor. In this innovative design, a significant departure from the conventional switched reluctance motor is observed, as modifications are made to the rotor with the goal of reduction torque ripple and radial force characteristics. Importantly, despite these advancements, the proposed motor retains the weight and volume characteristics of the traditional, type. The key attributes of these motors have been thoroughly assessed using the three‐dimensional finite element method, complemented by a sensitivity analysis aimed at identifying the most optimal configuration within the proposed design. The findings reveal that the suggested structure successfully achieves a notable reduction in torque ripple and radial force when compared to the traditional counterpart, albeit with an expected reduction in average torque. These features render the new topology particularly well‐suited for applications that prioritise noise and vibration reduction. Furthermore, the effectiveness of the proposed topology is corroborated through experimental tests, providing empirical evidence of its advantages and potential for practical applications. [ABSTRACT FROM AUTHOR]

Summary: This article proposes a hybrid POA‐RBFNN approach for PV (photovoltaic) based grid tied intelligent controlled water pump system. The proposed method is the hybrid wrapper of Pelican Optimization Algorithm (POA) and Radial Basis Function Neural Network (RBFNN) and later it is termed as POA‐RBFNN method. On the basis of bidirectional power grids, this research presents bidirectional power flow control for PV systems. The water pump is driven through a three‐phase synchronous reluctance motor (RSM). A novel Cuk integrated Landsman converter can operate at low duty cycles to provide larger DC voltages with negligible switching losses is used. In addition, to enhance the pumping system reliability, solar panels and electric pumps can be used to their maximum potential. Despite fluctuating weather conditions, the system supplies nominal displacement all over the day and surplus energy to the grid. Furthermore, if one of the sources fails, the pump performance is unaffected. Switching losses are minimized since the Voltage Source Inverter (VSI) operates at a fundamental frequency. In all operational modes, this control delivers unique grid‐side power quality and unity power factor functioning. Here, the performance of the proposed hybrid system is implemented in the MATLAB and is compared with several existing methods. [ABSTRACT FROM AUTHOR]

Harmonic magnetic gears (HMGs) have the advantage of lubrication‐free, high speed ratio and high torque density, which make it an attractive solution for safety critical applications. Due to eccentricity caused by machining and assembly, HMG suffers from dynamic eccentricity (DE) in operation, however, its effect on HMG performance is still unknown. Transmission characteristic of HMG under DE is studied. First, a magnetic equivalent circuit (MEC) model of HMG is proposed to build the magnetic coupling torque analytically, and the geometry of air gap is analysed parametrically to derive its equivalent reluctances. Flux density and coupling torque can be acquired by solving MEC equations. The accuracy of the MEC model is verified by finite element method. To study the transmission characteristic, an electromechanical coupling simulation framework for HMG is constructed, motion trajectories of rotors are investigated in case of DE, the output torque in locked‐rotor condition and speed response in continuous operation can be derived by simulation. It is found that torque ripples that have the same frequency with input rotor are induced by DE; the results are then verified in the experiment. This paper provides a theoretical guidance for the design and condition monitoring of HMG. [ABSTRACT FROM AUTHOR]

The authors present a new design of a PM‐assisted synchronous reluctance motor (PM‐SynRM) with uneven air‐gap length to improve the power factor and enhance the torque production capability. The rotor structure is modified to properly shift rotor magnetic poles and therefore (i) increases the back‐EMF and the electromagnetic torque, (ii) allows electromagnetic torque and reluctance torque components peak near the same current phase angle. The proposed solution is simple, does not require changing the arrangement of magnets and/or flux barriers and is applicable to all types of PM‐SynRMs. Sensitivity analysis is carried out to determine the extent of which the proposed magnetic pole shifting may impact the resultant torque profile. To assess the level of success, the electromagnetic characteristics of the proposed design (e.g. torque, power factor, and back‐EMF) are compared against the baseline structure under the same operating conditions. For verification purposes, Finite Element simulation results are validated via a series of analytical calculations and experimental measurements, and supported with detailed theoretical discussion. [ABSTRACT FROM AUTHOR]

Direct Instantaneous Torque Control (DITC) with an adaptive turn‐on angle technique is presented in this paper to improve the torque ripple of the Switched Reluctance Motor (SRM) for Electric Vehicle applications. Torque ripple suppression is achieved by employing two operating modes during the commutation interval. First, both the outgoing and incoming phase states are modified to track the required torque during the incoming phase's minimum inductance area. As soon as the incoming phase leaves its minimum inductance zone, the outgoing phase is demagnetised, and only the incoming phase state is modified for torque tracking. In addition, a closed‐loop regulator is used to dynamically control the turn‐on angle that drives the incoming current to reach its first peak at the instant of switching between the two operation modes when the rotor and stator poles initiate overlap, thus increasing the motor's efficiency. Simulation results showed that the proposed control method has superior advantages over the traditional DITC and Average Torque Controller. Furthermore, the simulation results were verified experimentally using a four‐phase 4kW, 8/6 SRM prototype. [ABSTRACT FROM AUTHOR]

This study proposes a space vector pulse width modulation (SVPWM) driving method for the switched reluctance motor (SRM), which enables the use of a standard full‐bridge power converter to drive a three‐phase SRM with a ring structure, in place of the traditional asymmetric H‐bridge (AHB). Based on this driving topology, the SVPWM approach is employed to drive the SRM, and its performance is compared with that of the conventional SRM driving method utilising the AHB. The findings indicate that the SVPWM method can effectively reduce torque ripple in the SRM. Moreover, the experimental validation performed to verify the proposed driving topology and method yields results that closely align with the simulated outcomes. [ABSTRACT FROM AUTHOR]

The rotor of the axial split‐phase bearingless switched reluctance motor (ASPBSRM) is structured with convex poles. The magnetic flux between the stator and the rotor varies with the rotor position, resulting in time‐dependent displacement stiffness and current stiffness coefficients of the suspension force. This scenario leads to a time‐varying characteristic of the suspension system. This study analyzed the electromagnetic characteristics of the suspension force in the ASPBSRM to characterize the time‐varying suspension system accurately. The study elucidated the hinge relationship between the magnetic flux in the suspension system and the rotor position. Moreover, a mathematical model for the suspension force considering the magnetic flux multitooth hinge was constructed by leveraging the advantages of the Maxwell stress method for the localized modelling and adopting the concept of the main edge magnetic path parallel analysis. Finally, the effectiveness of the model was verified through finite element analysis. [ABSTRACT FROM AUTHOR]

Doubly salient electromagnetic machine (DSEM) can constitute a competitive rugged starter generator (SG) system. But under the traditional startup control method, the field current is set to the rated value regardless of speed or load torque conditions, and the phase currents are controlled with standard angle commutation, bringing in large power loss as well as non‐negligible torque ripple. To overcome these shortcomings, based on the established DSEM power loss calculation model, a currents distribution strategy is proposed according to the obtained quantitative relationship between DSEM power loss and field current under multiple speed and load torque conditions. Then, to identify the load torque for practical implementation, a novel torque observer is designed based on back propagation (BP) neural network algorithm. Afterwards, to further improve the startup torque performance, currents distribution with advanced angle commutation (AAC) strategy is put forward, where the optimal advanced angle is selected from a 3‐D lookup table to achieve the minimal commutation torque ripple. Under the proposed control strategies, DSEM power loss as well as the output torque ripple are desired to be decreased, the simulation and experimental results on a 12/8‐pole DSEM prototype verify the correctness and feasibility of the proposed strategies under multiple operating conditions. [ABSTRACT FROM AUTHOR]

A calculation model of radial electromagnetic force wave for permanent magnet assisted reluctance motor (PMaSynRM) with rotor slots is proposed in this paper. By introducing complex air gap relative permeance, the improved magnetic potential permeability method is applied to the calculation of electromagnetic force wave of the PMaSynRM. Considering the influence of both stator and rotor slots, the characteristics of electromagnetic force wave are analyzed theoretically. A multi‐physical coupling model of PMaSynRM is established. The natural frequency of the stator core is obtained by modal finite element analysis and modal hammer experiment. The harmonic response is analyzed by loading electromagnetic force wave into the structure field and the vibration on the housing surface is calculated. The results show that although the amplitude of electromagnetic force is small at zero‐order slot frequency, the vibration caused by electromagnetic force at frequency of stator slots and rotor slots, especially at the rotor slot frequency, is the biggest vibration source. The effectiveness and regularity of the calculation model are verified by the prototype vibration experiments. © 2023 Institute of Electrical Engineer of Japan and Wiley Periodicals LLC. [ABSTRACT FROM AUTHOR]

The regulation and stabilization of a system's output to achieve desired performance and ensure system reliability require the use of different controllers, but selecting appropriate control parameters presents a challenge in ensuring robustness and stability. Proportional–integral–derivative (PID) controllers are popularly used due to their simplicity and effectiveness in addressing these challenges. In this paper, a simple, effective, and efficient, novel graphical technique is proposed to design PID and its variants (PI/PD) controllers, which addresses the challenges in selecting appropriate control parameters. The method involves creating three equispaced vectors for controller parameters (Kp,Ki,Kd)$(K_{\text{p}}, K_{\text{i}}, K_{\text{d}})$, and obtaining a 3D (2D in PI/PD) Cartesian grid of these vectors. All nodes in the grid provide several possible controllers, and integral time squared error (ITSE) is calculated for each controller from the closed‐loop step response of the system. The obtained ITSE is plotted in a 4D (PID) or 3D (PI/PD) graph, and controller parameters corresponding to the minimum value of ITSE are identified. Furthermore, the proposed graphical technique aids in choosing the lower and upper bounds (LB and UB) if the controller is designed using optimization techniques. The better selection of LB and UB reduces the search space resulting in lesser execution time and fewer iterations. To validate the proposed graphical technique, we designed various controllers for widely‐used brush‐less DC and switch reluctance motors in electric vehicles. Additionally, by choosing the LB and UB with the proposed technique, controllers are also designed using three optimization techniques: particle swarm optimization, black widow optimization algorithm, and honey badger algorithm. The obtained controllers using the graphical technique outperformed the optimization techniques in terms of time and frequency domain specifications, and the proposed selection of lower and upper bounds resulted in improved performance in terms of iterations and execution time. [ABSTRACT FROM AUTHOR]

Here, the authors propose two new Permanent Magnet (PM) embedded linear switched reluctance motors; one is a modular linear hybrid reluctance motor (MLHRM), and the other one is a segmental linear hybrid reluctance motor (SLHRM). Both structures employ PMs between the side teeth of the modules/segments. The main contribution of the PMs is to increase the air‐gap flux density, which results in an enhanced thrust, and decrease the magnetic saturation in iron parts. The magnetic equivalent circuit model is used to demonstrate the positive effect of inserting PMs in the MLHRM and SLHRM compared to their PMless counterparts. The optimal pole number and design procedure are illustrated. The simulation results are obtained in terms of static thrust, flux linkage, flux density distributions, and steady‐state current and thrust. The results show that the proposed MLHRM and SLHRM offer a higher thrust and lower current compared to their PMless form. Also, the PMs decrease the root mean square (RMS) current under the steady‐state performance of the motors, in which a higher thrust is produced with a lower RMS current. Finally, the MLHRM and SLHRM are fabricated and the test results are obtained and compared with the simulations, which illustrate a satisfactory agreement. [ABSTRACT FROM AUTHOR]

This study elaborates upon a new modular split‐tooth permanent magnet‐assisted switched reluctance motor (MSTPM‐SRM). In the proposed topology, the stator comprises six modular E‐cores in which the middle poles are split into two teeth. Two permanent magnets (PMs) are placed between each module's middle and side poles. Primarily, the proposed topology is introduced. Next, the principle of operation of the proposed topology are elucidated, and the magnetic equivalent circuit analysis is adopted in order to validate the operational basics. It is proved that the embedded PMs significantly increase the air‐gap's flux density and adjusts the poles' flux density. The flux density distributions, static, and steady‐state characteristics of the proposed MSTPM‐SRM motor and its PMless counterpart are extracted by utilising 2‐D finite element analysis. It is illustrated that the average torque of the proposed MSTPM‐SRM is dramatically increased compared to its PMless counterpart, especially at high excitation currents. Furthermore, the cogging torque analysis is done and it is shown that the proposed structure has approximately zero cogging torque. Finally, a prototyping version of the proposed motor is fabricated, and the experimental results are elicited. It is shown that the experimental results endorse the simulation results. [ABSTRACT FROM AUTHOR]

This paper presents an evolutional topology optimization of electric machines, which works like gradient‐based local search methods, based on the covariance matrix adaptation evolution strategy (CMA‐ES). The present method enables to improve the performance of initial machine shapes without computing the deviation of the objectives. Moreover, for the resultant shapes obtained by the present topology optimization method, this paper also presents a sensitivity analysis method based on the normal distribution which is used to seek for solutions in CMA‐ES. Using the present sensitivity analysis method, important parts which contribute to improve a machine characteristic can be visualized. The two present methods are applied to the optimization problem of a synchronous reluctance motor. It is shown that initial rotor shapes defined by designers can effectively be modified using the present optimization method. Moreover, it is also shown that the sensitivity distributions with respect to some machine characteristics are visualized by the present method. In addition, each machine characteristic is respectively improved by modifying the machine shape according to the respective sensitivities. © 2022 Institute of Electrical Engineers of Japan. Published by Wiley Periodicals LLC. [ABSTRACT FROM AUTHOR]

Fractional‐slot concentrated‐windings are appreciated for their simple construction, short end‐winding length, high copper fill factor, low cogging torque, good field‐weakening capability and fault‐tolerant ability. However, in comparison to the conventional distributed windings, the fractional‐slot concentrated‐windings are characterised with high space magnetomotive force (MMF) harmonics, which results in undesirable effects on the machine performance, such as localised core saturation, eddy current loss in the rotor and noise and vibration. In order to improve winding characteristics, several techniques have been developed recently. This manuscript introduces the 5 new winding topologies by using the general concept of stator slot shifting. It means that, in order to cancel undesirable MMF harmonics, by doubling (or tripling or even multiplying) the slot number and dividing the winding and then relatively shifting the winding by one (or more) slots, the undesirable harmonics have been eliminated effectively. The best choice is chosen according to the lowest amount of the MMF harmonic, highest value of winding factor and torque desirable characteristics. At the end, comprehensive comparisons for the designed synchronous reluctance motor (SynRel) equipped with proposed windings and also distributed winding are presented. The analytical study and 2D FEM analysis results show that it is possible to get an ideal low space‐harmonic winding topology, and consequently, a low torque ripple for these motors. [ABSTRACT FROM AUTHOR]

In this paper, we propose a novel multi‐objective topology optimization with response surface approximation interpolating various topologies, which is derived by deep learning with training data in the actual design space. The response surface is constructed by means of autoencoder with the training data of geometrically diverse shapes of targeted devices, which can express the interpolations that combine the multiple characteristic structures. The global topology search is performed based on the gradient information of the response surface, by which we can obtain the initial shapes for level set optimization to efficiently obtain easily manufactured and excellent Pareto optimal solutions. The effectiveness of the proposed method is demonstrated by optimizing multi‐flux barriers in a synchronous reluctance motor for the objective functions of average torque and torque ripple. © 2022 Institute of Electrical Engineers of Japan. Published by Wiley Periodicals LLC. [ABSTRACT FROM AUTHOR]

This paper reports on a novel unipolar current excited control scheme for the asymmetric bridge converter (ABC)‐based switched reluctance drive (SRD), where the 3D space vector modulation under three modes is developed to reduce the total harmonic distribution (THD) and torque ripple. Firstly, two different 3D vector distributions, namely, the small voltage amplitude mode and large mode are presented based on the asymmetric converter. For both distributions, the zero‐sequence voltages generated by the effective vectors are considered. Additionally, zero‐sequence vectors (1,1,1) and (−1,−1,−1) are no longer treated as null vectors and involved in the control of zero‐sequence current. Then, the duty cycles of both two modes are obtained by the combination of the zero‐sequence and two adjacent active vectors. Moreover, based on the large modulation mode, a novel method combined with the small mode is proposed to further optimise the switching costs and torque ripples. The effectiveness of the proposed modes is verified through the simulation in MATLAB and the experiment on a dSPACE‐1103‐based prototype. Compared with the conventional switched reluctance motor vector control, the proposed scheme delivers better performances of THD, efficiency and torque ripple reduction. [ABSTRACT FROM AUTHOR]

This paper investigates the accuracy of rotor‐locked transient‐response (RLTR)‐based vibration model for switched reluctance machines (SRM). RLTR is stator vibration stimulated by abrupt change of radial force when turning off one phase of SRM with rotor being locked, the total vibration of SRM can be modelled as linear superposition of RLTR series. An electromechanical model is built to clarify the generation of SRM vibration, it is revealed that some velocity‐depend terms in electromechanical model would be neglected when rotor is locked, it leads to inevitable difference of RLRT between rotor‐locked condition and rotational condition, the difference is illustrated through multi‐physics simulation. A harmonic radial force model is proposed to quantitatively evaluate the accuracy of RLTR‐based vibration model, radial force spectrums with locked rotor and rotational rotor are compared to predict relative error between RLTR‐based vibration and actual vibration. The influence of turn‐off angle and velocity on accuracy of RLTR‐based vibration model is also analysed. The accuracy of RLTR‐based vibration model is evaluated through experiment on 3‐phase 12/8 SRM, the results showed that: (1) the accuracy of RLTR‐based vibration model is impacted by turn‐off angle and velocity; (2) relative error between RLTR‐based vibration and actual vibration can be predicted using harmonic radial force model. This paper illustrates the generation mechanism of modelling error for commonly used RLTR‐based vibration model of SRM, the proposed error prediction method could lead to improved accuracy on SRM vibration model through error compensation. [ABSTRACT FROM AUTHOR]

This paper introduces a variable magnet switched reluctance motor (VM‐SRM) drive that can be characterized with adjustable performance. It consists of a switched reluctance (SR) motor with low coercive force (LCF) magnets buried on stator yoke and a modified asymmetric half bridge (AHB) converter. Magnetization level of the LCF magnets is adjusted by injecting a current pulse to a phase winding of the VM‐SRM. The magnetization process does not need any extra coil and provides a simplicity owing to modified AHM converter. Possible magnetic saturation that limits the magnetization level is overcome by injecting current pulses to two phase windings at the same time. Thus, LCF magnets can be used with their full capacity. The presented analysis results demonstrate that proposed VM‐SRM drive provides a variable performance and might be a candidate for future variable speed applications. © 2022 Institute of Electrical Engineers of Japan. Published by Wiley Periodicals LLC. [ABSTRACT FROM AUTHOR]

This paper presents an analytical modelling technique based on modified winding function and co‐energy analysis, for characterisation of synchronous reluctance machines, in conjunction with a hybrid algorithm for mapping of the machine's operating point on BH curve and the corresponding performance parameters in non‐linear magnetic condition. The model successfully provides the mean torque and the torque profiles of a synchronous reluctance motor as a function of input current and load‐angle in the magnetic linear and non‐linear conditions. The obtained results of this proposed model are compared with finite‐element‐analysis (FEA) based commercial design software Simcentre‐MAGNET. The comparison proves this model's capability to estimate the machine's performance parameters with considerable accuracy from an already established design analysis technique, FEA. The proposed modelling technique requires only a fraction of simulation runtime when compared to other design analysis techniques. Considering the accuracy of this modelling technique and the least requirement of computation resources and simulation time, this model can be used as an initial iterative‐design tool for mass personalised, additively manufactured electrical machines where rapidness of the iterative design analysis tool is of paramount importance. [ABSTRACT FROM AUTHOR]

A linear switched reluctance motor (LSRM) is designed for electric propulsion application in a Magnetically Levitated (Maglev) train with the base speed of 7.6 m/s and operating at a maximum of 27.8 m/s. In such high‐speed LSRMs, windage loss is one of the key issues of concern. Usually, windage loss accounts for approximately 0.5% below the base speed, 20% above the base speed, and 45% at higher speeds of the total loss of the LSRM. One of the many parameters affecting this windage loss is the stator slot profile. This research work studies about different stator slot structures, thereby aiming to reduce the windage loss through computational fluid dynamics analysis. Furthermore, experimental testing of the LSRM is also done to verify the simulation results. [ABSTRACT FROM AUTHOR]

This paper proposes an automatic design method of typical parameters such as number of phases, number of poles, stack thickness, stator outer diameter, rotor outer diameter, and number of turns of a switched reluctance motor from the requirement of the N‐T characteristic. In particular, a specific parameter related to the magnetic saturation is defined in order to arbitrarily determine how much to use the magnetic properties of the iron core material. In the proposed method, the typical motor parameters in order to realize a miniaturized volume which satisfies an input N‐T characteristic are obtained by setting the parameter related to magnetic saturation, maximum electrical frequency, maximum current density, maximum copper loss, conductor slot fill factor, magnetic properties of material, and input voltage. The designed motor is analyzed using the Finite Element Method (FEM) in order to validate the proposed method. [ABSTRACT FROM AUTHOR]

Power generation through renewable sources using a multistage power conversion process was plagued with efficiency and reliability issues. It led to the evolvement of a novel universal converter for the simultaneous interfacing of solar and wind energy. Solar energy is extracted using a multiphase boost converter, while a 2n converter with a switch reluctance generator has been used for wind energy extraction. In this paper, a novel universal converter is used to integrate both solar and wind energies, which will reduce multiple stages of the power conversion process. This converter generates an output voltage of the sino‐square waveform, which is a combination of a sinusoidal and square waveform. Enhanced efficiency and competency of this sino‐square waveform in domestic and industrial applications have been validated with a systematic comparison with conventional square waveform. These two waveforms have been compared based on various harmonics generation, total harmonic distortion (THD), and switching losses. The proposed topology has been validated with an experimental setup using a PV emulator for solar energy. Wind energy has been implemented using an induction motor with switch reluctance generator. [ABSTRACT FROM AUTHOR]

To accurately predict motor performance, considering the effects of core losses is of great importance, especially at speeds much higher than the base where the core losses represent a considerable portion of the total drive losses. Neglecting the effects of core losses leads to an error in the switched reluctance motor (SRM) performance prediction. In this study, a previously developed non‐linear SRM model with multiphase coupling is extended by considering the instantaneous effects of core losses on the SRM performance. Using the new model, the nature of these effects is determined. A comparison of the simulation results of the proposed, basic, and finite element method (FEM) model confirms the importance of considering the effects of core losses on motor performance. Besides the FEM model, the accuracy of the proposed model is verified by experiments. [ABSTRACT FROM AUTHOR]

The modelling and analysis of Brushless Doubly Fed Reluctance Machines (BDFRMs), taking into account magnetic saturation and rotor movement, by conventional modelling techniques are very difficult, if not impossible, because the two stator windings have different number of poles leading to a complex flux pattern. To overcome this drawback, Finite Element Analysis (FEA) is generally used for modelling and analysing BDFRMs. But it requires a considerable computational time compared with semi‐analytical methods. This article, therefore, steps forward by proposing a new approach to dynamical modelling of BDFRM based on the Reluctance Network Method (RNM), which can enable accurate calculation of the electromagnetic parameters and performances of BDFRMs. Indeed, the reluctance network method offers an interesting compromise between precision and computation time compared to finite element analysis. To validate the proposed model, simulations are carried out and comparison are made with FEA. It is observed that the greatest error between the values of the proposed model and those from FEA is close to 1%. The accuracy in the calculation of electromagnetic parameters, as well as the computational time leads us to the conclusion that the proposed model could be suitable for optimisation and control purposes. [ABSTRACT FROM AUTHOR]

To obtain a short flux path and improve the torque performance, a double‐phase excitation (DE) was generally used for switched reluctance motor (SRM). But the torque ripple of the SRM working under DE with traditional winding distribution increases because of the inconsistent electromagnetic field. To deal with this problem, an 8/6 SRM working under DE with novel winding distribution (DESRM) is proposed here. In order to comprehensively analyse the electromagnetic performance of DESRM, it is compared with a traditional single‐excitation SRM and double‐excitation SRM with traditional winding, in terms of air flux density, radial and tangential force components, inductance, torque, and losses. The theoretical and finite element analysis results reveal the cause of differences on torque and vibration of the motor as well as the mechanism of generating different motor performance. In addition, the analysis shows that the proposed DESRM generates a higher torque with a reduced torque ripple. Finally, a pair of prototypes with different winding configurations is designed and used to verify the theoretical analysis. [ABSTRACT FROM AUTHOR]

A permanent magnet synchronous motor (PMSM) is introduced with 120° phase belts toroidal windings (PBTWs) (120°PBTWPMSM), in which its armature reaction field principle is elaborated. Then, the experiment concerning the 120°PBTWPMSM is conducted to verify the validity of the related analysis and the feasibility of the 120°PBTWPMSM. In addition, a method of shifting the magnetic poles (SMP) is adopted to suppress the cogging torque and the torque ripple. After this, the 120°PBTWPMSM after SMP is further optimised by the Taguchi method to obtain the structural parameters of the motor with optimal comprehensive performance. Finally, the performance of the original motor, the 120°PBTWPMSM after SMP and the optimal motor are compared, which verify the effectiveness of the optimization methods. [ABSTRACT FROM AUTHOR]

A new semi‐analytical expression is presented based on two integrations for calculating the magnetic force of a solenoid inductor wound by rectangular cross‐section wire. The authors simplified the solenoid inductor coil to a collection of circular coils, and the current density of the coils in the radial direction which was inversely proportional to its radius is considered. The obtained expressions can be implemented by adaptive Gaussian quadrature integration with MATLAB programming. In addition, they used the filament method and the finite element method to calculate the magnetic force on the solenoid inductor coil. The correctness of the semi‐analytical expressions was verified by comparing the results of the semi‐analytical numerical method with those of the filament method and the finite element method, respectively. The derived semi‐analytical expressions of magnetic force allow a low computational time compared with the filament method and the finite element method to a specific accuracy. The calculation results show that: the solenoid inductor coil tends to compress in the axial direction, and the axial magnetic force on the outermost coils is the largest; the solenoid inductor coil tends to expand outward in the radial direction, and the radial magnetic force on the intermediate coil is the largest. [ABSTRACT FROM AUTHOR]

Here a new sensitive fault detection criterion is proposed, based on the stationary wavelet transform (SWT) decomposition components of the stator currents, for the online detection of stator winding turn‐to‐turn faults at an early stage of development. The energies of the desired detail components are calculated and the normalized Euclidean distance of the energy differences between the three phases is used as a new fault detection criterion. The robustness of the proposed technique against the presence of rotor turn‐to‐turn faults and loading variations is demonstrated. In addition, an adaptive threshold level as a function of the voltage unbalance factor is proposed to guarantee the robustness of the diagnostic technique against unbalanced voltage sources. Experimental results demonstrate the effectiveness and sensitivity of the proposed diagnostic approach for the detection of stator faults in line‐connected and inverter‐fed motors. [ABSTRACT FROM AUTHOR]

Asymmetrical rotor topologies were previously proposed for synchronous reluctance motors (SynRM) to reduce the torque ripple. However, potential negative effect of these topologies on mechanical vibration, which is often serious in SynRM, was hardly studied and such an effect is investigated here. An analytical model is established, through which the spatial orders of the radial electromagnetic force with various rotor topologies are derived, and the relationship of the peak frequencies and the corresponding spatial orders in the radial electromagnetic force is revealed. It is shown that some asymmetric rotor topologies will reduce the order of the lowest spatial harmonic for the radial electromagnetic force, and consequently increase the vibration. Finite element analysis and experiments demonstrate the same results. Finally, a specific rotor topology with asymmetry about both d‐axis and q‐axis is recommended, which can reduce the torque ripple, but would not deteriorate the radial electromagnetic force and vibration. [ABSTRACT FROM AUTHOR]

Summary: In this article, the equivalent control strategy based on Laplace transform is proposed for the problem of stochastic delay in networked control systems. The original system is transformed into an equivalent control system without random delay block by Laplace transform. Then, a new augmented variable and equivalent control system is introduced to construct an augmented system. An adaptive fault diagnosis observer is designed based on the augmented system. The adaptive turning rate of the observer is obtained by solving the corresponding linear matrix inequality. Based on the information of online fault diagnosis and state estimation, a fault‐tolerant controller based on PI control strategy is designed to compensate the fault. Finally, a model of the switched reluctance motor system is considered to show the effectiveness of this method. [ABSTRACT FROM AUTHOR]

A novel dual 6/3 Transverse Flux Bearingless Switched Reluctance Motor is proposed to solve the coupling problem between torque and suspension of conventional Switched Reluctance Motor. The working principle is introduced in detail, the motor is modelled by ANSYS, and the accurate mathematical model of the suspension force is deduced and verified. The electromagnetic characteristics of the motor are simulated, and the torque characteristics, suspension characteristics and the coupling characteristics between them are verified. The simulation results show that the torque and suspension force can be stabilised by using the zoning control of torque and suspension force, and the decoupling between torque and suspension force is excellent. [ABSTRACT FROM AUTHOR]

Switched reluctance motors (SRMs) are considered as a potential candidate in many high‐reliability demanding applications, including electrical vehicles (EVs), hybrid EVs and more electric aircrafts. For precise and stable control performance, normally an SRM drive requires one current sensor for each phase winding. Failure of any of these sensors will inevitably degrade the system's performance. The behaviour of an SRM drive under current sensor failure is investigated and a fault‐tolerant control technique is proposed by changing the current sensor installation scheme without adding extra current sensors. Moreover, through the analysis of the detected currents by the phase current sensors and the dc‐link sensor, a diagnostic scheme for current sensors failure is presented. The excitation current in the faulty phase under postfault conditions is reconstructed through a simple calculation without injecting a high‐frequency signal or modifying the switching signals, thereby reducing the current distortion and avoiding voltage penalty issues. Motor drive can operate with satisfactory control performance even when all the phase current sensors are in fault conditions. Detailed analysis under both steady state and dynamic conditions through thorough simulations and experiments has been carried out on a three‐phase 12/8 SRM. The extensive results validate the effectiveness of the proposed technique. [ABSTRACT FROM AUTHOR]