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This paper proposes a unified control method based on an improved grey wolf optimization algorithm to improve the performance of the switched reluctance motors (SRMs) to cope with various operating conditions. Compared with the single control mode of traditional SRMs, an SRM with 12/10 poles is called a multimode switched reluctance motor, which can be used not only as a six-phase motor but also as a three-phase motor. The control method proposed is based on a 12/10 pole SRMs. In the TSRM mode, an improved torque sharing function with parameters is utilized to reduce torque ripple and widen the speed range. In the SSRM mode, the linear active disturbance rejection control (LADRC) method is used to increase the anti-interference ability of the system. For the switching modes, an improved gray wolf optimization algorithm is designed to ensure smooth switching. The global optimal solution is obtained by introducing the coyote group to avoid falling into the local optimal solution. Finally, the experimental results prove the effectiveness of the control method. • The 12/10 SRM is used as a TSRM mode and a SSRM mode. And a unified control method is proposed. • The proposed method uses an improved TSF and the LADRC method in different modes and they can switch smoothly. • In TSRM mode, an improved TSF with tunable parameter is proposed to reduce the torque in a wide speed range. • An improved grey wolf packs optimization algorithm for introducing coyote packs is designed. • The proposed method can reduce torque ripple within 23.5% in the rated speed range. [ABSTRACT FROM AUTHOR]

In this paper, a novel magnetic parameter design methodology is proposed for switched reluctance motors (SRMs). Based on the nonlinear characteristic of flux linkage, the design equations of structural and winding parameters are derived. The benefit is that there are no meaningless empirical design coefficients in the proposed design methodology. Three SRMs with multiple phases, i.e., 12/8, 10/8, and 18/20 stator/rotor poles SRMs, are initially designed according to the derived equations. Then, multiobjective optimization is carried out to realize the design objectives of output torque, current density, and torque ripple. The design solutions of the three SRMs with similar current density and slot fill factor are selected from the Pareto front, respectively, and the performance comparisons are conducted. The proposed design methodology is verified by the selected optimal solutions after the substitution into the design equations. Finally, the designed SRMs are prototyped and tested to validate the simulation results and further verify the effectiveness of the proposed design methodology. [ABSTRACT FROM AUTHOR]

This article proposes an improved method for the position signal evaluation of a switched reluctance motor (SRM) drives. It can perform accurate position signal reconstruction based on the inductance, and greatly increase the fault tolerance of SRM in complex environments. It includes the position signal fault diagnosis (PSFD), position signal estimation, and fault-tolerant control (FTC). First, the installation and principle of the position sensor is introduced to show the function of the position signal in SRM drive system. Then, to overcome the limitation of application range of the conventional diagnosis method, a new PSFD method based on grey prediction model is proposed. Besides, a position estimation method based on the inflection point of the inductance is proposed. According to the estimated position, FTCs are carried out when position sensors are faulty. Finally, experiments are carried out to validate the effectiveness of the proposed position signal fault-tolerant control method based on a 12/10 six phase SRM. [ABSTRACT FROM AUTHOR]

In this paper, a design optimization method is proposed to reduce the current asymmetric and consequent torque ripple for a six-phase Switched Reluctance Motor (SRM). First, the inconsistent current phenomenon of the investigated SRM is introduced, and the relationship between the magnetic distribution and the phase currents is investigated by magnetic circuit analysis. Then, for the reduction in computational cost, a surrogate model is utilized to establish the response surface model between the optimization objectives and variables. Furthermore, multiobjective optimization is performed based on structural design optimization and asymmetric control, and the best design solution is selected for the drive system. Compared with the traditional symmetric control, it can be found that the proposed asymmetric control can mitigate the inconsistent phase currents and reduce the torque ripple. Finally, a prototype motor is manufactured and tested. Both the simulation and experimental results verify the effectiveness and the reasonability of the analysis and the optimization. [ABSTRACT FROM AUTHOR]

This paper proposes a new position sensorless method for switched reluctance motor (SRM) drive control based on a sliding mode observer using nonlinear Fourier flux linkage model. First, to obtain an accurate mathematical model of SRM for establishment of sliding mode position observer (SMPO), an analytical method based on Fourier polynomial function is introduced to regress the nonlinear relationship between flux linkage, position and current. Then, a new SMPO is designed in detail to estimate the rotor position, including the establishment of SRM model of sliding mode observer, and analysis of estimation error and convergence conditions of SMPO. Finally, position sensorless control of SRM drive based on SMPO is carried out in terms of accuracy and robustness in simulation. Experiments are also given on a dynamic testing platform to verify the effectiveness of the proposed position sensorless scheme. [ABSTRACT FROM AUTHOR]

This paper presents a new sensorless control strategy with the fault-tolerant ability for switched reluctance motors (SRMs). Nowadays, many rotor position detection methods are utilized, but most of them increase the system cost due to the additional hardware or complex calculations. To address this problem, various methods of using phase inductance to estimate the rotor position and speed have been proposed. However, the traditional inductance detection method will cause signal distortion due to the presence of interference signals and the unbalanced phase inductance. In particular, the turn-ON angle is advanced. To further improve the stability of the control system, the interference signals are eliminated via establishing the reference time of the inductance characteristic point and the error band in this work. When the position signal disappears, the inductance characteristic points of adjacent phases will be adopted for signal compensation to realize fault-tolerant control. Finally, an SRM drive system is used to verify the effectiveness of the proposed control strategy. [ABSTRACT FROM AUTHOR]

This article presents an optimal direct torque control (DTC) strategy with variable flux for a switched reluctance motor using the improved linear active disturbance rejection control (LADRC) plus the hybrid optimization algorithm (HOA). First, the constant flux amplitude is substituted by the variable flux DTC (VF-DTC) to reduce the torque ripple. Then, the LADRC with the improved extended state observer applied in speed controller is utilized instead of the conventional PI control to improve the speed of the observer, antidisturbance ability, and robustness. Moreover, the HOA is employed to search for the optimal control parameters and acquire satisfactory dynamic performances. Finally, the optimal VF-DTC system is implemented on a 12/8 SRM. Simulation and experimental results are carried out to compare the performances of the conventional DTC, the VF-DTC with LADRC, the VF-DTC with PI using HOA, and the proposed optimal VF-DTC using HOA. The results show that the proposed control method has a faster speed response, superior antidisturbance ability, and lower torque ripples. [ABSTRACT FROM AUTHOR]

In this paper, a new system-level sequential Taguchi method (SLSTM) is proposed to achieve the optimal solution with high robustness for switched reluctance motor (SRM) drive systems. An SRM drive system consisting of a segmented-rotor SRM and the angle position controller is investigated as a case study. In the implementation, the optimization function contains torque, loss, and torque ripple. The control factors of the system are selected according to the sensitivity analysis results. Manufacturing tolerances are considered to guarantee that the optimal solution features low sensitiveness to uncertainties. The process of defining the design levels of all the control factors and noise factor is illustrated and the orthogonal array is established. The optimization of the SLSTM is carried out sequentially until the certain convergence condition is satisfied. Finally, the component-level sequential Taguchi method (CLSTM) is carried out for comparison. It appears that the proposed SLSTM is efficient in searching for the robust optimal solution for the SRM drive system. Besides, it can achieve better output performance, such as higher average torque and lower torque ripple, and a higher level of robustness compared with the initial design and CLSTM. [ABSTRACT FROM AUTHOR]

Switched reluctance motors (SRMs) have attracted much attention in industry due to the advantages of low cost, robust structure, high fault tolerance and high torque density. However, several disadvantages like high torque ripples and coil temperatures hinder their industrialization for some applications requiring high dynamic performance, like electric vehicles (EVs). In this paper, a multiobjective and multiphysics design optimization method considering both thermal and electromagnetic performance is presented for a 12/10 SRM. First, the topology of the SRM is introduced and the optimal parameters are defined. Then, the electromagnetic finite element model (FEM) is introduced and the 3D transient lumped-parameter thermal model (TLPTM), considering both axial and radial heat transfer for the SRM, is proposed. Second, the objectives and constraints of the optimization are determined. To improve the optimization efficiency, the sequential subspace optimization strategy is employed to find the optimal solution of this high-dimensional design optimization problem. Finally, to validate the effectiveness of the proposed method, both simulation and experimental results are given and discussed. Compared with the initial design, the optimal solution exhibits lower temperature, higher torque, lower torque ripple and less loss. [ABSTRACT FROM AUTHOR]

In this article, an improved direct instantaneous torque control (DITC) based on adaptive terminal sliding mode control (ATSMC) is proposed to suppress torque ripple and enhance the anti-interference ability for switched reluctance motors (SRMs). The proposed speed controller used in the outer loop of DITC is based on the rate of change in load torque. The state of the system converges quickly to the equilibrium point and realizes fast output of the given torque without known disturbance upper bound. Moreover, a novel reaching law is proposed to reduce torque ripple and startup time. The stability of the adaptive terminal sliding mode motion is verified by using the Lyapunov function. The improved DITC system is implemented on a 16/10 segmented-rotor SRM. Compared with sliding mode control and terminal sliding mode control, the proposed ATSMC in the DITC system behave with better performances in aspects of the speed and torque response, antiinterference ability, robustness, and torque ripple suppression. Simulation and experimental results are given to verify the effectiveness of the improved DITC. [ABSTRACT FROM AUTHOR]

The industrial application of the switched reluctance motor (SRM) is limited by its high torque ripples caused by the doubly salient structure. In this article, an improved direct torque control (DTC) with sliding mode controller and observer is developed to reduce the torque ripples of a four-phase SRM. First, a sliding mode controller based on a new reaching law is developed for designing a sliding mode speed controller (SMSC) for the DTC system. An antidisturbance sliding mode observer (ADSMO) is then proposed and combined with the SMSC to build a composite antidisturbance speed control strategy. Moreover, detailed simulation validations are carried out to reveal the effectiveness of the new reaching law, SMSC and ADSMO. Finally, experiments are conducted to verify the performance of the proposed SMSC–ADSMO in a DTC system with a four-phase SRM prototype. [ABSTRACT FROM AUTHOR]

The belt-driven starter/generator (BSG), as a cost-effective solution, has been widely employed in hybrid electric vehicles (HEVs) to improve the stability and reduce the fuel consumption of the vehicles. It can provide more than 10% reduction in CO2. Electrical machine is the heart of the BSG system, which is functioned both as motor and generator. In order to optimize both aspects of motor and generator simultaneously, this paper presents a new multimode optimization method for the switched reluctance machines. First, the general multimode concept and optimization method are presented. The switched reluctance motor and the switched reluctance generator are the two operation modes. The optimization models are established based on motor and generator functions. Sensitivity analysis, surrogate models and genetic algorithms are employed to improve the efficiency of the multimode optimization. Then, a design example of a segmented-rotor switched reluctance machine (SSRM) is investigated. Seven design variables and four driving modes are considered in the multiobjective optimization model. The Kriging model is employed to approximate the finite element model (FEM) in the optimization. Finally, the optimization results are depicted, and an optimal solution is selected. The comparison between the initial and optimal designs shows that the proposed method can improve the foremost performance of the SSRM under all driving modes. [ABSTRACT FROM AUTHOR]

In this article, a novel system-level robust design optimization method is presented to improve the performance of switched reluctance motor (SRM) drive systems under multiple operating conditions. Based on typical driving cycles of electric vehicles (EVs), five typical driving modes of the SRM are determined. The optimization objectives in each driving mode are established. The significant parameters of the motor and controller of each driving mode are selected as the optimization variables by using the sensitivity analysis. In order to simplify the optimization process, correlation analysis is performed to determine the coherence of the objective functions of all driving modes. Then, a sequential Taguchi method is applied to find an optimal design which is less sensitive to the noise factors. To verify the effectiveness of the proposed method, an SRM drive system applied in EVs with a 12/10 SRM and angle position control method is investigated. It is found that the proposed method can significantly reduce the torque ripple and improve the comprehensive performance. Finally, a 12/10 SRM is prototyped and tested to validate the simulation results. [ABSTRACT FROM AUTHOR]

This article presents a novel multiobjective system level optimization method to achieve the best performance of switched reluctance motor (SRM) drive systems. First, the multiobjective optimization problem for the SRM drive systems is defined. Then, all parameters of the drive systems, including the motor level and control level, are divided into three subspaces according to their influences on the objectives. Finally, the optimization of each subspace is performed sequentially until a convergence criterion is met. Then, the optimal solution can be chosen from the Pareto solutions according to a selection criterion. Meanwhile, the sensitivity analysis, the approximate models, and the genetic algorithm are employed to reduce the computation cost. To verify the effectiveness of the proposed method, an SRM drive system with a segmented-rotor SRM (SSRM) and the angle position control method is investigated. This is a high-dimensional system level optimization problem with ten parameters. The finite-element model (FEM) results are verified by the experiment results. The optimal solution has been listed and verified by the FEM. From the discussion, it can be found that the proposed optimization method is efficient and optimized SSRM drive system has high efficiency and low torque ripple. [ABSTRACT FROM AUTHOR]

This article presents a new magnetic equivalent circuit (MEC) for a real-time emulation of a 16/10 segmented-rotor switched reluctance motor (SSRM) based on the hardware-in-the-loop (HIL) configuration. The proposed real-time MEC contains the reluctances of slot leakage, air gap, and iron core of the SSRM. To speed up the emulation, a ten-by-ten matrix system is developed for the MEC. A new algorithm is proposed to solve the matrix system to reduce the computation time. To carry out the experiment, the HIL is employed in this article. It can provide a precise and real-time condition for the application of the new method. In the test bench, the field-programmable gate array provides an operating platform to realize the real-time emulation of the MEC model. As verified, the proposed real-time MEC model benefits the real-time emulation and the performance evaluation of the SSRM. The proposed method can be applied to other switched reluctance motors as an efficient way to verify their real-time characteristics with high accuracy and low emulation cost. [ABSTRACT FROM AUTHOR]

This work presents the analysis, design and optimization of a permanent magnet synchronous motor (PMSM) for an electric vehicle (EV) used for campus patrol with a specific drive cycle. Firstly, based on the collected data like the parameters and speed from a test EV on the campus road, the dynamic calculation of the EV is conducted to decide the rated power and speed range of the drive PMSM. Secondly, according to these requirements, an initial design and some basic design parameters are obtained. Thirdly, optimization process is implemented to improve the performance of the designed PMSM. The permanent magnet (PM) structure, airgap length and stator core geometry are optimized respectively in this step. Different optimization processes are proposed to meet multiple optimization objectives simultaneously. Based on the finite element analysis (FEA) method, it is found that the harmonic of the optimized PMSM is lower than that of the initial design, and the torque ripple is reduced by 24%. The effectiveness of optimization on the core loss and PM eddy loss is validated and the temperature rise is suppressed effectively. Finally, a prototype is fabricated for the optimized PMSM and an experimental platform is developed. The test results verify that the optimized PMSM meets the requirements of the specific campus patrol EV well. [ABSTRACT FROM AUTHOR]

This paper investigates the design principles and performance optimization for segmented-rotor switched reluctance motors (SRSRMs) with different rotor pole numbers for belt-driven starter generators of hybrid electric vehicles. For the design principles, several constraints are derived for the numbers of stator and rotor poles, the dimensions, and the number of winding turns. Two SRSRMs with 16/10 and 16/14 stator/rotor poles are presented according to these principles. For the performance optimization, the two motors are optimized individually for maximizing the torque. To evaluate the effect of different segmented-rotor numbers, the overall performances of the two SRSRMs are investigated and compared. It is found that the 16/14 SRSRM has higher flux linkage and static torque. The 16/14 SRSRM exhibits higher torque and lower torque ripple at low speed operation, whereas at high speed, the 16/10 SRSRM performs better in terms of torque and power densities. Compared with the 16/14 SRSRM, the 16/10 SRSRM has higher final steady speed under the same startup condition. The 16/10 SRSRM can achieve higher steady speed under starter mode and provide higher generated power under braking mode. Moreover, the 16/10 SRSRM exhibits higher efficiency in the most feasible speed range, especially in high speed range, and it has wider high-efficiency area. Finally, a 16/10 SRSRM is prototyped and tested to validate the simulation results. [ABSTRACT FROM AUTHOR]

Due to the advantages such as high energy density, high power density, high cyclic life, and environmentally friendly, the flywheel battery has the potential to solve the problem of energy storage. In order to improve the torque density and suspension performance of bearingless synchronous permanent magnet (PM) synchronous motors (BPMSMs), a novel rotor structure with V-shaped PMs is designed in this paper. Furthermore, the interior BPMSM (IBPMSM) with V-shaped PM which used for flywheel batteries of electric vehicles is researched in detail. Especially, the influence of geometrical parameters of V-shaped PM on suspension force and electromagnetic torque is investigated. Moreover, the corresponding static electrical magnetic characteristics including inductances and electromagnetic torque are also studied. The finite-element method is employed to evaluate the theoretical analysis of the proposed IBPMSM. In addition, the optimized motor is validated to have good suspension performance by some experiments. [ABSTRACT FROM AUTHOR]