Optimized Power Factor Correction for High Speed Switched Reluctance Motor

The Power Factor Correction(PFC)in Switched Reluctance(SR)motor is discussed in this article.The SR motors are applicable for multiple applications like electric vehicles,wind mills,machineries etc.The doubly salient structure of SR motor causes the occurrence of torque ripples,which affects the power factor of the motor.To improve the power quality,the power factor has to be corrected and the ripples have to be minimized.In order to achieve these objectives,a novel power factor correction(PFC)method is proposed in this work.Here,the conventional Diode Bridge Rectifier(DBR)is replaced by a Bridgeless Hybrid Resonant(HR)converter,which assists in improvising the output in a wider range.The converter is chosen because of having variety of beneficial measures including high gain.The converter’s output is fed to the SR motor by means of an asymmetric Bridge Resonant(BR)converter.The proposed converter operates in continuous mode of conduction with the switching frequency of 10 KHz.A hysteresis current controller and Proportional Integral(PI)controller are utilized for reducing the harmonics in the source current along with the regulation of output voltage.In addition,the speed control of SR motor is accomplished by means of the Whale Optimization Algorithm(WOA)assisted PI controller.The proposed methodology is effective for the control of unity power factor,torque and current ripples.The Total Harmonic Distortion(THD)of the source current is also minimized,which suits the standard of International Electrotechnical Comission IEC 61000-3-2.By this methodology,the power factor of 0.99 is achieved with 97%efficiency and 3.92%THD.The proposed methodology is validated in simulation by MATLAB and in hardware by FPGA Spartan 6E.

An Analytic Method of Segmented PWM Duty Cycle for Switched Reluctance Motor

In view of the large current peak and torque ripple in the actual current chopping control of switched reluctance motor,a segmented PWM duty cycle analysis method of switched reluctance motor based on current chopping control is proposed in this paper.The method realizes the control of the winding current by adjusting the average voltage of the two ends of the winding in one cycle through the PWM duty cycle.At the same time,according to the inductance linear model,the conduction phase is divided into a small inductance region and an inductance rising region,and the analytical formulas of PWM duty cycle in the two regions are deduced respectively.Finally,through matlab/simulink simulation and motor platform experiment,the current chopping control is compared with the segmented PWM duty cycle analysis method in this paper.Simulation and experimental results show that the segmented PWM duty cycle analysis method can effectively reduce the current peak and torque ripple,and has high practical application value.

Accurate Torque Modeling With PSO-Based Recursive Robust LSSVR for a Segmented-Rotor Switched Reluctance Motor

In order to improve the reliability in torque calculation of SRM,an accurate nonlinear torque model regresses by recursive robust least squares support vector regression(RR-LSSVR)is proposed in this paper.The model is in terms of a segmented-rotor switched reluctance motor(SSRM).The characteristics of the SSRM is introduced to show its nonlinear characteristics both in magnetic and torque.Then,its mathematic model is established,and an accurate inductance measurement method and a torque calculation method are presented.After this,the principle of the RR-LSSVR and why it can adjust weights according to errors are described.The model used the RR-LSSVR algorithm shows an outstanding capability in accuracy and quickness compared with other algorithms.Finally,to further validate the accuracy of the proposed model in practical application,simulation and experiment are designed based on a 16/10 SSRM.

Optimal design of linear switched reluctance motor for sea wave power generation

The switchless reluctance motor’s non-permanent magnet structure design ensures its high reliability in the marine environment;thus,it is a feasible solution for the generator of a sea wave power generation system.However,the corresponding thrust density and efficiency remain insufficient.This study focused on a new type of flat linear switched reluctance motor(LSRM),using the finite element software to establish a structural model,and optimized the design with the goal of improving the efficiency and energy density.The entropy method was adopted for sensitivity stratification to objectively select weights to avoid the influence of subjectively selected different proportional weights on the optimization results.Based on the entropy method,the sensitivity of different structural parameters was stratified,and the simulated annealing algorithm,response surface method,and single parameter scanning method were combined for optimization.Finally,the optimal structural size parameters of the motor were determined.Based on the two-dimensional finite element method,to simulate the electromagnetic performance of the reluctance motor under different operating conditions,such as thrust,loss,and efficiency,changes in motor performance before and after optimization were compared to verify the high power generation efficiency and energy density of the optimized linear motor.

Winding Inductance and Performance Prediction of a Switched Reluctance Motor with an Exterior-rotor Considering the Magnetic Saturation

This paper deals with an analytical method to effectively calculate the inductance of an exterior-rotor switched reluctance motor(SRM),which evaluates the winding inductance of both the active section and the end section,accounting for the influence of core saturation.According to the inductance calculated by the analytical model,the flux linkage table and torque table can be established,and the steady state performance such as phase current,flux linkage,copper loss and core loss can be predicted.Effectiveness of this method is verified by the finite element method as well as by experimental results of a 12/8 SRM prototype.

Design andtwo-objective simultaneous optimization of torque controller for switched reluctance motor in electric vehicle

In order to reduce the torque ripple,increase the average torque and optimize the drive performance of the switched reluctance motor (SRM),the nonlinear dynamic model of SRM is established in the MATLAB /Simulink environment.The effects of the turn-on and turn-off angles are investigated by the simulation results of the dynamic model,and the function is made among the rotor speed,turn-on angle and turn-off angle.To optimize the torque dynamic performance,the two-objective simultaneous optimization function is proposed by two weight factors.And the optimized turn-on and turn-off angles as functions of rotor speed are developed by using the simultaneous optimization method.Then the optimized torque controller is designed based on the optimized turn-on and turn-off angles.The simulation results show that the optimized torque controller designed in this paper can effectively reduce the torque ripple and increase the average torque,and optimize the torque dynamic performance of the SRM.

Design and Analysis of Asymmetric Rotor Pole Type Bearingless Switched Reluctance Motor

Bearingless switched reluctance motor(BSRM) not only combines the merits of bearingless motor(BM) and switched reluctance motor(SRM), but also decreases the vibration and acoustic noise of SRM, so it could be a strong candidate for high-speed driving fields. Under the circumstances, a 12/14 BSRM with hybrid stator pole has been proposed due to its high output torque density and excellent decoupling characteristics between torque and suspension force. However, this motor has torque dead-zone, which leads to problems of self-start at some rotor positions and large torque ripple during normal operation. To solve the existing problems in the 12/14 type, an asymmetric rotor pole type BSRM is proposed. The structure and design process of the proposed motor is presented in detail. The characteristics of the proposed motor is analyzed and compared with that of the 12/14 type. Furthermore, prototype of the proposed structure is designed, manufactured and experimented. Finally, simulation and test results are illustrated and analyzed to prove the validity of the proposed structure.

Comparative Investigation of Torque-ripple Suppression Control Strategies Based on Torque-sharing Function for Switched Reluctance Motor

Torque ripple is an inherent property of switched reluctance motor(SRM),which seriously affects the control performance and application of the motor.This paper proposes two torque ripple suppression control strategies based on torque-sharing function(TSF).According to the symmetry characteristics of the flux linkage and rotor position curve family,a fourth-order Fourier series is used to fit the SRM flux linkage analytical model.The coefficient of each harmonic term of the flux linkage model is a function related to current,expressed by a sixth-order polynomial.The torque analytical formula can be derived from the flux linkage model.The torque error is calculated via the identified torque model and is compensated through TSF controller in order to reduce torque ripple.The torque model can also be used to establish the torque loop to achieve accurate tracking of the TSF reference torque to reduce torque ripple.Digital simulation was conducted,followed by the implementation on a SRM test bench using a 28335DSP as the master control chip.The experimental results are consistent with the simulation results,and indicate the effectiveness of the proposed schemes.

Performance Prediction of Switched Reluctance Motor using Improved Generalized Regression Neural Networks for Design Optimization

Since practical mathematical model for the design optimization of switched reluctance motor(SRM)is difficult to derive because of the strong nonlinearity,precise prediction of electromagnetic characteristics is of great importance during the optimization procedure.In this paper,an improved generalized regression neural network(GRNN)optimized by fruit fly optimization algorithm(FOA)is proposed for the modeling of SRM that represent the relationship of torque ripple and efficiency with the optimization variables,stator pole arc,rotor pole arc and rotor yoke height.Finite element parametric analysis technology is used to obtain the sample data for GRNN training and verification.Comprehensive comparisons and analysis among back propagation neural network(BPNN),radial basis function neural network(RBFNN),extreme learning machine(ELM)and GRNN is made to test the effectiveness and superiority of FOA-GRNN.

Switched Reluctance Motor: Research Trends and Overview

There has been a growing interest in switched reluctance motor(SRM)ever since the development of thyristor in 1956.The most appealing feature of SRM which attracts researchers over these years is its simple structure that incorporates concentrated windings on the stator poles and plain laminations of ferromagnetic material as a rotor.Due to this attributes,advances are being made rapidly with the consideration that SRM can be used as an alternative to DC motors and permanent magnet motors.The objective of this paper is to present an overview of the recent developments and a prediction of possible future advancements in SR Drives.Brief history,importance,innovations in structure and control,along with practical application examples are all discussed here to give a more in-depth comprehension of the motor.

Research on DTC System with Variable Flux for Switched Reluctance Motor

When switched reluctance motor(SRM)is in the status of the traditional direct torque control(DTC)system,due to the high saturation nonlinearity of the electromagnetic relationships of switched reluctance motors,the torque ripple and the stator phase current are larger.In order to resolve the above problems,through the analysis and deduction for SRM flux model and the influence of characteristics of flux and speed on torque ripple,this paper presents a variable-flux control strategy with the three closed-loop structure based on the critical flux supersaturated speed.And a DTC system of SRM with variable flux and three closed-loop is built up in Matlab/simulink.Moreover,the DSP hardware experiment platform based on the TMS320F2812 is established to validate the performance of the improved algorithm.The simulation and experimental results show that the new scheme has an obvious effect on torque ripple reduction,and the three-phase stator current is obviously reduced,which greatly reduces the stator winding copper consumption during the operation of SRM.Moreover,the improved system has good system stability.

Simulation analyzing of torque-ripple minimization for switched reluctance motor

Discusses the inevitability of torque ripple of switched reluctance motor (SRM) for its double saliency construction and switch power supply, and the minimization of torque ripple, under traditional current chopping control mode, and presents a varying current amplitude chopping control method with a linear control model of varying current amplitude chopping shown, and the simulation of torque profiles under two kinds of current chopping control modes to demonstrate the validity of decreasing torque ripple.

Review of Linear Switched Reluctance Motor Designs for Linear Propulsion Applications

Linear switched reluctance motor(LSRM)and its applications in different industries have been an interesting research topic for the past few years.LSRMs have proved to be a suitable alternative in a variety of applications requiring linear motion.However,its use is not that popular which instigated an active interest in the evolution of newer LSRM configurations.Enhancement in its propulsion force along with the reduction in force ripples,weight,acoustic noise,and vibration have been the main objectives in recently proposed LSRM designs.In this paper,recently proposed LSRM designs are reviewed and analyzed.The paper presents a one-stop introduction and a complete update to the designs,both in terms of qualitative and quantitative parameters.In addition,it takes into account the challenges in the implementation of these designs.Based on a detailed comparison of these designs as presented in this paper,an appropriate design can be chosen for a given application.

Improved Model of Radial Vibration in Switched Reluctance Motor Including Magnetic Saturation

This paper proposes an improved method for the prediction of radial vibration in switched reluctance motor(SRM)considering magnetic saturation.In this paper,the basic modeling principle is briefly introduced,it is based on the derivation that the peak acceleration is dependent on the product of phase current and current gradient idi/dt.However,the derivation may cause errors due to saturation effect.Thus in this paper,the discrete sample data are firstly acquired based on DC pulse measurement method,by which electromagnetic,torque and peak acceleration characteristics can all be acquired.Then the entire peak acceleration characteristics are obtained by improved Least Square Support Vector Machine(LSSVM).Based on the obtained static peak acceleration characteristics,the time-varied radial vibration model is established based on superposition of natural oscillations of dominant vibration modes.Finally,a simulation model is built up using MATLAB/Simulink.The good agreement between simulation and experiment shows that the proposed method for modeling is feasible and accurate,even under saturation.In addition,since LSSVM does not need any prior knowledge,it is much easier for modeling compared with other existing literatures.

High Frequency Charging Techniques—Grid Connected Power Generation Using Switched Reluctance Generator

Power generation becomes the need of developed, developing and under developed countries to meet their increasing power requirements. When affordability increases their requirement of power increases, this happens when increased per capita consumption. The existing power scenario states that highest power is produced using firing of coals called thermal energy. A high efficiency Switched Reluctance Generator (SRG) based high frequency switching scheme to enhance the output for grid connectivity is designed, fabricated and evaluated. This proposed method generates the output for the low wind speed. It provides output at low speed because of multi-level DC-DC converter and storage system. It is an efficient solution for low wind power generation. The real time readings and results are discussed.

ANFIS Based Space Vector Modulation-DTC for Switched Reluctance Motor Drive

Direct torque control (DTC) of Switched reluctance motor is known straightforward control structure with similar execution to that of field situated control strategies. In any case, the part of ideal determination of the voltage space vector is one of the weakest focuses in a routine DTC drive because of adjustable switching frequency and high torque ripple. In this paper, ideal choice of voltage space vectors is accomplished utilizing ANFIS (Adaptive Neuro Fuzzy Inference System) with space vector Modulation. SVM-DTC gives consistent switching frequency and the proposed ANFIS controller’s structure manages the torque and stator flux error signals through the fuzzy deduction to get a yield that takes the type of space voltage vector. Simulation results accept the proposed evolutionary system with quick torque and flux reaction with minimized torque ripple and flux ripple.

An Improved DITC Control Method Based on Turn-on Angle Optimization

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.

Vector Control Strategy of a T-type Three-level Converter Driving a Switched Reluctance Motor

A novel 12 voltage vector control strategy for switched reluctance motors(SRM)with a T-type three-level converter is proposed in this study.Based on a causal analysis of torque ripple under the control of conventional six voltage vectors,six new voltage vectors are added for further reduction of torque ripple.An optimized control rule is adopted based on the division method of the 12 new voltage vectors.A zero-voltage vector is used to adjust the duration of the 12 voltage vectors,the time of which is varied at different parts of the vector sectors according to the torque error.In addition,the windings are connected in a delta configuration,therefore,the number of connections between the converter and SRM is reduced.Finally,the results of MATLAB/Simulink and RT-LAB are presented to verify the validity of the proposed scheme.

High Speed SRM Using Vector Control for Electric Vehicle

The high speed motor is effective to realize downsizing motor in an electric vehicle(EV).Switched Reluctance Motor(SRM)is possible to the high speed drive because the rotor structure has simple and robust.However,the vibration and the acoustic noise are large from the drive principle.Moreover,the conventional complicated current excitation results in the difficulty of the torque controller design.To overcome these problems,the vector control has been proposed for SRM drive.However,the vector control has not been applied to the SRM in the high speed drive.In this paper,the drive conditions such as switching frequency,bus voltage for driving the SRM in the high speed region are clarified.It is shown that the proposed SRM can be driven by the vector control in the high speed region and can realize low vibration.

FPGA Based Speed Control of SRM with Optimized Switching Angles by Self Tuning

The electromagnetic torque and speed in Switched Reluctance Motor (SRM) greatly depend on the excitation parametersi.e. turn-on angle, turn-off angle, dwell angle and magnitude of the phase currents of its phases. At lower speeds, a change in the current contributes the torque requirement which can be achieved either by voltage control (pulse width modulation) or instantaneous current control techniques. At high speeds, due to high back EMF, the regulation of current is crucial and achieved with the control of switching angles of phases. This type of control is referred as average torque control, where the torque is averaged over one stroke (2π/Nr). With constant dwell angle, advancing the phase angle influences the current into the phase winding at minimum inductance position. It has more time to get the current out of the phase winding before the rotor reaches the negative inductance slope. To maintain the speed of the motor at different load conditions, the turn-on and turn-off angles are adaptively varied. The change in dwell angle may be required where the turn-on and turn-off angle may not be sufficient to reach the required speed. In this paper, a new algorithm is proposed for self tuning of switching parameters of SRM. The proposed algorithm is simulated in MATLAB-Simulink and experimentally validated with Field Programmable Gated Array (FPGA) using MATLAB- system generator environment.