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.

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.

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.

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.

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.

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.

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.

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.

Direct torque control of doubly fed induction motor using three-level NPC inverter

This article presents the direct torque control (DTC) strategy for the doubly fed induction motor (DFIM) connected to two three-level voltage source inverters (3LVSIs) with neutral point clamped (NPC) structure. This control method allows to reduce the torque and flux ripples as well as to optimize the total harmonic distortion (THD) of motor currents. The use of 3LVSI increases the number of generated voltage, which allows improving the quality of its waveform and thus improves the DTC strategy. The system modeling and control are implemented in Matlab/Simulink environment. The analysis of simulation results shows the better performances of this control, especially in terms of torque and flux behavior, compared to conventional DTC.

Position Sensorless Torque Estimation of Synchronous Reluctance Motors Based on Extended-Flux Model without Core-Loss Measurement

This paper proposes an extended-flux model with core-loss resistance of SynRMs （synchronous reluctance motors） and precise torque estimation without core-loss measurement and position encoder. The proposed torque estimation is useful for precise MTPA （maximum torque per ampere） control of position sensorless controlled SynRMs, which is achieved with the assistance of active and reactive powers.

Performance Comparison of Field-oriented Control,Direct Torque Control,and Model-predictive Control for SynRMs

Simulation studies of three synchronous reluctance motor(SynRM)control strategies are presented:field-oriented control(FOC),direct torque control(DTC),and finite-set model-predictive control(FS-MPC).FOC uses linear controllers and pulse-width modulation to control the fundamental components of the load voltages vectors.In contrast,DTC and FS-MPC are nonlinear strategies wherein the voltage vectors are directly generated in the absence of a modulator.Theoretical operating principles and control structures of these control strategies are presented.Moreover,a comparative analysis of the static and dynamic performance of the control strategies is conducted using Matlab/Simulink to identify their advantages and limitations.It is confirmed that each of the control strategies has merits and that all three of them satisfy the requirements of modern high-performance drives.

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.

一种优化开关磁阻电机换相区控制策略的高效率转矩分配函数

转矩分配函数被广泛应用于抑制开关磁阻电机的转矩脉动。然而,输入相转矩跟踪不足或者输出相产生较大的负转矩这两种情况通常会导致电机的转矩脉动难以得到有效抑制,并降低电机的运行效率。因此,为了能够有效降低电机的转矩脉动并提高电机的效率,提出了一种新型的转矩分配函数控制策略。在提出的转矩分配函数控制策略中,电机的换相区域分为两个区域。在前一区域中,通过降低输入相转矩分配的比例,可以实现输入相实际转矩快速跟踪参考转矩,电机的转矩脉动有效降低。同时由于在输入相电感变化率较低时减少输入相分配的转矩,从而输入相的峰值电流随之降低,电机的转矩电流比提高。在后一区域中,将输出相的电流在转子对齐位置附近处减小到0,以避免产生较大的负转矩。因此,在所提出的方案下,电机的转矩脉动得到有效抑制,电机的效率也得到了提高。为了验证该方法的有效性,在一台12/8三相开关磁阻电机上进行了仿真和实验。结果表明,所提出的转矩分配函数控制策略能有效降低开关磁阻电机转矩脉动,也能有效地提高开关磁阻电机的运行效率。

双三相同步磁阻电机单相开路故障下的容错控制策略

双三相同步磁阻电机(dual three-phase synchronous reluctance motor,DTP-SynRM)转子不含永磁体,没有高温退磁风险,成本较低,且由于其系统自由度高、冗余性强,因此具有较好的容错性能。开路故障是双三相同步磁阻电机系统中最常见的故障类型之一,该文针对一种两套三相绕组中性点相互独立的双三相同步磁阻电机单相开路故障,建立DTP-SynRM矢量空间解耦模型,实现对电压、电流和磁链方程的完全解耦。在开路故障状态下仍将其视为一个正常的双三相电机,分析故障状态对电机的电流约束和信号传递的影响,并指出在开路故障下z2轴电流与β轴电流不再独立,电机由正常运行时的四阶系统降阶为三阶系统,而由于开路故障导致的电压信号传递不准确则会在dq坐标系中引入二次谐波电流,并产生二次和四次转矩波动。该文提出一种同时考虑电流约束和信号传递误差的故障容错方法,电机处于三闭环运行状态,补偿电压信号传递误差,抑制开路故障时电机的转矩波动并降低电流谐波。搭建实验平台进行实验,验证所提容错方法的有效性和可行性。

基于改进型转矩分配函数的开关磁阻电机转矩与峰值电流优化研究

开关磁阻电机(SRM)使用传统的转矩分配函数控制时由于转矩分配函数的开关角度恒定,使其在换相阶段出现较为明显的转矩脉动和较高的峰值电流现象。针对这一现象,提出实时调节开关角度的指数型转矩分配函数的控制方法来降低转矩脉动与相峰值电流。与传统的转矩分配控制进行比较分析,所提算法能够在不同电机转速下抑制转矩脉动和降低SRM定子绕组换相峰值电流,在中低速情况下,实时优化转矩分配函数开关角与重叠角,提高了SRM的运行效率。以一台2.2 kW的12/8开关磁阻电机作为控制对象,建立控制系统仿真模型,通过仿真和实验验证了所提算法的有效性。

基于自然容错开关表的五相永磁同步电机直接转矩控制

五相永磁同步电机(permanent-magnetsynchronous motor,PMSM)传统直接转矩控制(direct torque control,DTC)存在相电流畸变严重、共模电压(common-modevoltage,CMV)高、转矩和磁链脉动大等问题,且无法实现相开路故障情况下的无扰运行。为解决上述问题,提出一种基于自然容错开关表的DTC策略。该策略根据PMSM开路故障前后基电压矢量的特点以及三次平面合成电压矢量为零的原则,构建虚拟矢量(virtual vector,VV),设计故障前后同一套自然容错开关表,进而不但抑制了故障导致的转矩脉动,而且在故障前后均能降低三次谐波电流、减小转矩和磁链脉动、抑制CMV。实验结果验证所提策略的可行性。

Speed-assigned Position Tracking Control of SRM With Adaptive Backstepping Control

A novel speed-assigned method is applied to the position tracking control of switched reluctance motor(SRM).A speed control freedom can be drawn into the position control through speed assignment. Adaptive backstepping control is used to design the position controller for the SRM. The accuracy of position tracking of the SRM can be enhanced with speed assignment. A disturbance observer is further designed to enhance the estimation accuracy of the unknown load torque. Simulation results certify that the design scheme is right and effective.

周向错角开关磁阻电机及其直接瞬时转矩控制

传统开关磁阻电机由于其双凸极定、转子铁心结构以及开关型供电方式会造成强转矩脉动。针对此问题,提出了一种新型低转矩脉动周向错角开关磁阻电机。结合电机结构介绍了其运行机理,并对绕组的电感特性和转矩出力进行了分析。该电机采用内-外双定子结构,转子上同时设置内凸极和外凸极,且内、外定子铁心之间以及转子内、外凸极之间在周向上均相互错开一定的角度。内定子极上绕有辅助绕组,可以在主绕组换相期间提供辅助转矩以补偿转矩跌落,从而降低转矩脉动。利用场路耦合联合仿真,分别构建了传统开关磁阻电机与周向错角开关磁阻电机的直接瞬时转矩控制系统,对比两者在匀速运行工况下的转矩脉动情况,结果表明相较于传统开关磁阻电机,周向错角开关磁阻电机的转矩脉动更小,具有良好的转矩脉动抑制效果。

车用永磁无刷直流电机弱磁控制仿真研究

永磁无刷直流电动机的转矩与转速会对电机的控制精度造成影响,导致电机弱磁控制效果差。为了提升整体控制性能,提出车用永磁无刷直流电机弱磁控制仿真方法。分析车用永磁无刷直流电机弱磁转矩特性,获取电机电磁转矩关系。根据获取结果建立永磁无刷直流电机弱磁控制系统,利用该系统控制电机弱磁的电磁转矩与运行效率,以此实现整体控制。实验结果表明,通过对所提方法开展电机运行效率测试、电机运行稳定性测试,验证了上述方法的有效性。

永磁同步电机三相矢量双选取预测转矩控制

针对永磁同步电机在占空比模型预测转矩控制下,存在计算量较大、稳态性能不够理想的问题,提出一种三相矢量双选取模型预测转矩控制方法。首先将定子磁链所在空间复平面6个扇区重新划分为3个扇区;其次,设计一种基于三相电压矢量的新型开关表,依据新型电压矢量选择表,从三相电压矢量中选择出两个有效电压矢量,再加入一个零矢量,仅进行一次占空比计算,就可输出任意幅值、相角的期望电压矢量。仿真结果表明,该策略减少了系统计算时间,有效地抑制了转矩和磁链脉动且稳态性能良好。