Switched Reluctance Motor Torque Research Articles

Review of Switched Reluctance Motor Converters and Torque Ripple Minimisation Techniques for Electric Vehicle Applications

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.

Suppression of Torque Ripple in Switched Reluctance Motors Which is Based on Synchronization Technology

The double salient pole structure of Switched Reluctance Motor (SRM) makes its electromagnetic field exist nonlinear saturation characteristics, resulting in its large torque pulsation in operation, so it is difficult to achieve speed regulation smoothly by traditional control methods. In view of this problem, a sliding mode control strategy which is based on synchronous transmission technology was proposed.Firstly, the basic structure of switched reluctance motor was analyzed, and the mathematical model of mechanical motion of switched reluctance motor was established. Secondly, an improved sliding mode controller which is based on synchronous signal transmission technology was designed by analyzing the reason of large torque ripple of switched reluctance motor, and the stability of the system was proved. Finally, simulation is used to verify the effectiveness of the control strategy.Compared with the traditional PID (Proportional Integral Differential) control algorithm, this control technology not only suppresses the SRM torque ripple effectively , but also makes the sliding mode controller output the precise target electromagnetic torque quickly by increasing the control variables. The results of research indicate that this design can not only restrain the torque ripple effectively, but also adjust the convergence speed and overshoot of the controller by adjusting the design parameters.

Switched Reluctance Motor Design and Optimization

In the field of electric vehicle engineering, Switched Reluctance Motors (SRMs) are progressively drawing the attention of developers for their streamlined structural design, superior torque output, economical cost-benefit, and excellent energy efficiency ratios. This paper takes a four-phase 8/6-pole switched reluctance motor as an example, with a rated power of 7.5Kw and a rated speed of 1500r/min. According to the basic design requirements of the SRM, the SRM parameter design flow is designed, and a Matlab calculation program is written for the preliminary calculation of the SRM parameters, and the detailed design of its motor structural parameters is carried out. After that, the stator and rotor pole arc coefficients of the SRM are parametrically analyzed using Maxwell2D tool according to the design experience, and the optimal stator and rotor pole arc coefficients are selected. The simulation results show that the design optimization scheme can effectively reduce the SRM torque pulsation.

Online Current Spikes Suppression Strategy Research of Switched Reluctance Motors Based on Hybrid Torque Sharing Function

In this paper, an online compensation predictive control method based on hybrid torque sharing function (HTSF) is proposed to reduce current spikes in the torque sharing control of switched reluctance motor (SRM). First, predictive control is introduced to the torque sharing function (TSF) and a new cost function is designed with Laplace multiplier method by predicting the current and torque of the next cycle of SRM. Then the optimal current control amount is carried out. Second, the ratio of the torque error to the desired torque and its derivative are compensated online to the current phase at the beginning of the commutation overlap period to accurately track the torque, and the torque distribution is optimized by a HTSF at the end of the phase change to further reduce the current spikes and suppress the torque ripple. Finally, the experiment on 8/6 four‐phase SRM is achieved to verify the feasibility and effectiveness of the proposed control strategy, and the results show that the current spikes and the torque ripple are reduced by 25% and 14.5% respectively. Therefore, compared with traditional TSF control, this method can effectively reduce the SRM torque ripple and excessive current spikes. © 2023 Institute of Electrical Engineer of Japan and Wiley Periodicals LLC.

Improved Torque Ripple of Switched Reluctance Motors using Sliding Mode Control for Electric Vehicles

This study describes the direct torque control-DTC approach, based on the Sliding Mode Control (SMC) technology with chattering reduction, for reducing the torque ripple of the Switched Reluctance Motor (SRM). The SRM torque control loop has been given the SMC treatment to account for the low-frequency fluctuations in the torque output. To maintain a consistent motor speed, the sliding mode controller modifies the value of the reference current. The findings demonstrate that the constant sliding mode controller is superior to PI controllers at lowering the motor's torque ripple, compensating for its nonlinear torque characteristics, and rendering the drive insensitive to parameter changes. MATLAB/SIMULINK simulation has been used to show how well this SMC performs. The performance of the proposed SMC method has been demonstrated by simulation in MATLAB/SIMULINK with a three-phase 8/6 pole, and a 2kW SRM.

Adaptive nonlinear current controller for switched reluctance motor torque ripple optimization

This paper deals with torque ripple minimization in SRM through adaptive nonlinear current control while considering saturation. The proposed methodology for SRM speed tracking is based on Indirect Instantaneous Torque Control (IITC). Optimal references are determined offline using the Particle Swarm Optimization (PSO) algorithm. The optimal current profile is generated by using current sharing function (CSF) block. The nonlinear speed and current controllers are developed using Backstepping technique. The proposed control strategy performance is evaluated using a Matlab Simulink model taking into account the saturation phenomena. The obtained results demonstrate that the adaptation of the control angles as well as the peak current minimizes the torque ripples for different operating conditions.

Sensitivity Analysis for Multi-Objective Optimization of Switched Reluctance Motors

The main issue of the switched reluctance motor (SRM) is its noise and vibration caused by high torque ripples on the rotor’s shaft. Many methods have been developed for improving the torque characteristic of the SRM. For example, design optimization is one of the promising approaches to the noise and vibration reduction of the SRM. Particularly, topology optimization (TO) of the stator and rotor can be highly beneficial to addressing the torque ripple issue. However, the TO of the SRM appears to be computationally demanding. To overcome this issue, this study proposes a method aiming to reduce the computational complexity of the TO through the reduction of the design space. Particularly, this paper presents a sensitivity analysis of a list of unique design parameters of the SRM and their influence on the average torque of the motor and the torque ripple of the motor. By applying the sensitivity analysis, the design space of the TO could be reduced, leading to a considerable decrease in the TO computational burden. Additionally, valuable conclusions on the geometrical parameters’ influences on the SRM torque and torque ripple have been drawn.

A Nonlinear SRM Controller Design for Torque Ripple Reduction with accounting for Magnetic Saturation

In this paper, a nonlinear backstepping controller design is proposed for torque ripple minimization in switched reluctance motor (SRM) drive systems, which ensures less acoustic noise and less vibration. The proposed controller is based on a model taking into account the stator coils magnetic saturation phenomenon. For the torque ripple optimization purpose, the excitation angles are adapted according to the instantaneous SRM torque and speed values. Therefore, a lookup table is built, proposing the excitation angles optimal values for different machine operation points. The proposed control strategy validation was carried out by simulation, using MATLAB-Simulink tools. More specifically, the Simpower system library was exploited, since it offers an SRM simulator, taking into account magnetic saturation. To highlight the supremacy of the proposed controller, its performances are compared with those of conventional linear (PI) regulator. The obtained results validate the proposed controller robustness and efficiency.

WITHDRAWN: Design of asymmetry converter to control SRM machine speed and torque ripple for electric vehicle applications

Industrially more useful Switched reluctance motor (SRM) is receiving additional research interest due to its various properties such as high‐speed operation, low cost, higher power density and independent of temperature. However, SRM has the drawbacks due to uncontrolled speed, vibration, noise, low efficiency and complex with low power. Hence, this work investigated the proposed model of asymmetry bridge converter with SRM to rectify speed control issue and torque instead of using C dump for electric vehicle applications. The simulations were carried using MATLB for the speed control of SRM. In addition this work discussed different topologies reported about SRM designs.

An Improved Torque Sharing Function to Minimize Torque Ripple and Increase Average Torque for Switched Reluctance Motor Drives

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

Torque–flux linkage recurrent neural network adaptive inversion control of torque for switched reluctance motor

In order to reduce the torque ripple for switched reluctance motor (SRM), the learning error preprocessing-based torque–flux linkage recurrent neural network adaptive inversion control (TFRNNAIC) for SRM torque is proposed by the filter preprocessing and the non-linear mechanism characteristics for SRM. In TFRNNAIC with the advantages of parallel and series–parallel structure, the torque feedback error learning method is employed to update the weights of the torque–flux linkage recurrent neural network. To suppress the ripple effectively in torque error used for the weight learning of the torque–flux linkage recurrent neural network and obtain an accurate TFRNNAIC, namely the torque–flux linkage model for SRM, the low-pass filter preprocessing for the torque error is used. Moreover, the other low-pass filter is executed to reduce the ripple in the output for the PD torque control. The superposition of outputs for TFRNNAIC and PD torque control is taken as the reference flux linkage. Compared with other control strategies, such as the classical parallel neural network control, the classical series–parallel neural network control and TFRNNAIC, the simulation results show that the learning error preprocessing-based TFRNNAIC for SRM torque is capable of effectively reducing the torque ripple for SRM with the good recurrent performance.

Influence of Control and Structure Parameters on the Starting Performance of a 12/8 Pole Switched Reluctance Motor

To investigate the influence of control and structure parameters on the starting performance of a switched reluctance motor, a 12/8 pole switched reluctance motor is analyzed in this paper. The novel field-circuit coupled finite element method of switched reluctance motor is proposed in the paper. The influence of the controller on the switched reluctance motor is considered. The influence of rotor initial position angle, starting mode, starting current, and structure parameters on the starting performance of the switched reluctance motor is studied using the field-circuit coupled finite element method. The starting performance of the switched reluctance motor is obtained under the different control and structure parameters. The alternating starting mode of single- and two-phase winding can improve the starting torque of switched reluctance motor (SRM). As the stator pole arc coefficient increases, the starting torque of SRM increases. The appropriate reduction of the air gap length can improve the starting torque of SRM. Experimental results of the prototype are compared with the calculation results, which verifies the reliability of the calculation method and accuracy of the calculation results.

Predictive Direct Torque Control of Switched Reluctance Motor for Electric Vehicles Drives

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

MFO-ANN based FOPID Controller for Torque and Speed Control of SRM Drive System

This paper proposed an optimal control algorithm based Fractional Order PID (FOPID) controller for the torque ripple minimization of Switched Reluctance Motor (SRM) drive system. That convalesce both control loop task, the Moth Flame Optimization (MFO)- Artificial Neural Network (ANN) algorithm is insinuated. The routine of intelligent technique is principally as the objective function of system error minimization. At this time the quality inspired algorithm of MFO is firstly reconnoitered to optimize the speed and torque error from the SRM system. Instead the output of MFO algorithm is optimized and to finding the premium value, the ANN method is recuperated. Nonetheless, the output of MFO-ANN is imperiled to the input of FOPID controller. For tweaking the exact FOPID gains, the multi objective functions are grew. Created on the operation of propositioned algorithm by normalize the system speed and minimalize the torque ripples of SRM system. The qualities of the suggested procedure are force falconer and in addition to augmented level of the reliability and flexibility in answering the system error. Also the enactment of proposed MFO-ANN process is executed in the MATLAB/Simulink running platform.

A Novel Structure of Switched Reluctance Machine With Higher Mean Torque and Lower Torque Ripple

Switched reluctance motors (SRMs) have a robust and simple structure, high reliability because of the absence of magnetic field source on rotor, low cost and simple cooling system. However, conventional SRMs confront with some challenges such as low mean torque, low torque density and high torque ripples. For wider applications of SRM, the above-mentioned drawbacks must be mitigated. One possible method is changing the structure of SRMs. In this article, a novel 12/14 three-phase SRM with connected C-core structure is introduced which has a short path for the main flux of stator teeth. This brings about core loss reduction. On the other hand, both teeth of the stator phase in C-core develop a positive torque during the movement of the rotor from the unaligned position to the aligned position; this enhances the torque, the mean torque and torque density of the proposed SRM, keeping the volume fixed. Finally, the proposed SRM was prototyped and tested and its torque/rotor angular position characteristic was measured. To verify the novelty and merits of the proposed SRM, its mean and peak torque, torque density, core losses and torque ripples were compared with those of an optimized 12/8 three-phase conventional SRM and a significant match was achieved.

A Switched Reluctance Motor Torque Ripple Reduction Strategy With Deadbeat Current Control and Active Thermal Management

This paper presents a switched reluctance motor (SRM) torque ripple reduction strategy with deadbeat current control and active thermal management. In this method, the SRM torque is indirectly controlled by the phase current. A deadbeat current control method is used to improve the SRM phase current control accuracy, so that SRM torque control error can be reduced significantly. According to the online measurement of the power switching device temperature, the switching frequency will be reduced to prevent the SRM power converter from being damaged by over-temperature. The feasibility and effectiveness of the proposed strategy have been verified in both simulation and experimental studies.

A Magnetic Bearing Switched Reluctance Motor With Simultaneous Excitation by a Modified Half-Bridge Converter

This paper presents a novel magnetic bearing switched reluctance motor (SRM) (MBSRM) with two degrees of freedom suspension, consisting of an SRM and an active magnetic bearing (AMB). In the proposed MBSRM, three-phase armature windings of the SRM and a biased winding of the AMB are fed together by a modified asymmetric half-bridge converter. The rotational torque in SRM and the biased flux used for producing electromagnetic force in AMB are generated simultaneously when the MBSRM works on the traditional switched reluctance excitation mode. First, the structure and working principle of the MBSRM were introduced. Second, its theoretical formulas of suspending forces were given and validated with the finite element analysis. Third, the proposed half-bridge converter is shown, and currents in the biased winding and three-phase armature windings of MBSRM are obtained by the magnetic field–circuit coupling simulation. Moreover, a prototype is manufactured and the experiment results have proved the feasibility of the proposed converter.

Methods of Torque Ripple Minimization Techniques on Switched Reluctance Motor

In recent decades, Switched Reluctance Motor (SRM) drive has proved to be an attractive alternate for the conventional industrial drives. Many published research works have proved that SRM drives finds significant application in almost all industrial sectors. This paper presents a comprehensive review on various control strategies of SRM drive implemented in literatures. The objective of this review is to identify the accurate control strategies for controlling the SRM speed and torque. This paper also reviews the various strategies for minimization of the torque ripples, acoustic noise and vibration in SRM

Direct Instantaneous Torque Control of the Switched Reluctance Motor for Electric Vehicles Applications Using Fuzzy Logic Control

This paper presents direct torque control of Switched Reluctance Motor (SRM) using Fuzzy Logic Control (FLC) for electric vehicles applications. The PD-FLC is proposed for SRM torque control, to keep the torque of the motor shaft in tracking the reference torque with high accuracy. With the help of FLC techniques, the SRM torque ripples can be reduced compared to traditional control techniques. In this study, the nonlinear 6/4 SRM model is simulated with the symmetrical converter, and the converter controller is programmed using C-language. The proposed method is tested at different load and variable speed conditions, and the obtained results confirm that the FLC direct torque control can be used for torque control to improve the motor performance and reduce the torque ripples compared to other techniques such as direct instantaneous torque control.

Direct torque and flux control of switched reluctance motor with enhanced torque per ampere ratio and torque ripple reduction

A smooth torque control of switched reluctance motor (SRM) is essential to avoid speed fluctuations causing stability problems in vehicular applications. This can be accomplished by an appropriate motor design and/or use of direct control of torque in SRM. It is reported that high RMS current is required to minimise the torque ripple in the conventional direct torque and flux control (DTFC), thereby reducing the torque per ampere ratio. To overcome this issue, a new DTFC technique with improved torque per ampere ratio while minimising torque ripple in an SRM traction drive is presented. Results demonstrated that the proposed DTFC technique reduces torque ripple with enhanced torque per ampere. Finally, the performance of the proposed scheme is compared with conventional DTFC of a four-phase (8/6) SRM to show the improvement in the traction drive.