A Novel Fuzzy Direct Torque Control System for Three-level Inverter-fed Induction Machine

Diode clamped multi-level inverter （DCMLI） has a wide application prospect in high-voltage and adjustable speed drive systems due to its low stress on switching devices, low harmonic output, and simple structure. However, the problem of complexity of selecting vectors and capacitor voltage unbalance needs to be solved when the algorithm of direct torque control （DTC） is implemented on DCMLI. In this paper, a fuzzy DTC system of an induction machine fed by a three-level neutral-point-clamped （NPC） inverter is proposed. After introducing fuzzy logic, optimal selecting switching state is realized by applying various strategies which can distinguish the grade of the errors of stator flux linkage, torque, the neutral-point potential, and the position of stator flux linkage. Consequently, the neutral-point potential unbalance, the dr/dr of output voltage and the switching loss are restrained effectively, and desirable dynamic and steady-state performances of induction machines can be obtained for the DTC scheme. A design method of the fuzzy controller is introduced in detail, and the relevant simulation and experimental results have verified the feasibility of the proposed control algorithm.

A Novel Multilevel Inverter Circuit for the Performance Enhancement of Direct Torque Controlled Induction Motor

Induction motor is the most sought after motor in the industry for excellent performance characteristics and robustness. Developments in the Power Electronic circuitry have revolutionised the induction motor industry leading to the developments in various control strategies and circuits for motor control. Direct Torque Control (DTC) is one of the excellent control strategies preferred by industries for controlling the torque and flux in an induction machine. The main drawback of DTC is the presence of torque ripple which is slightly more than the acceptable limit. There are various parameters that introduce ripples in the electromagnetic torque, one of them being the type of inverter circuit. There are various types of inverter circuits available and the effect of each of them in the production of torque ripple is different. This work is an attempt to identify the influence of various multilevel inverter circuits on the torque ripple level and to propose the best inverter circuit. The influence of multilevel diode clamped inverter and cascaded H bridge inverter circuits on torque ripple minimization, is analysed using simulation studies for identifying the most suitable multilevel inverter circuit which gives minimum torque ripple. The results obtained from the simulation studies are validated by hardware implementation on 0.75 kW induction motor.

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.

Modified Sliding Mode Observer-based Direct Torque Control of Six-phase Asymmetric Induction Motor Drive

In this study,a six-phase induction asymmetric induction motor(SPAIM)was examined,whose performance surpasses that of its three-phase counterpart,with regard to the torque density,torque pulsation,fault tolerance,power rating per inverter lag,and noise characteristics.Speed-encoder-less direct torque control(DTC)for SPAIM with virtual voltage vectors(VVVs)and a modified sliding mode observer(MSMO)are described.The SPAIM model was developed using a stationaryα-βframe for DTC.The conventional DTC of the SPAIM drive is a simple extension of DTC for a 3-Φmotor drive that yields higher distortion in the stator currents.To mitigate the large amount of distortion in the stator current,VVVs were used to significantly reduce the harmonic content in the stator currents.Furthermore,to overcome the large amount of chattering observed in the case of a traditional sliding mode observer,particularly under low-speed operation,the MSMO was employed to reduce chattering even under low-speed operation.The performance of the proposed observer was verified under all the operating conditions suitable for the propulsion mode of an electric vehicle using Matlab/Simulink,and the results were experimentally validated.

五相永磁同步电机改进型无差拍直接转矩和磁链控制

传统无差拍直接转矩磁链控制(DB-DTFC)策略应用于五相永磁同步电机(PMSM)时存在稳态性能差、转矩和磁链耦合、谐波电流大等问题,该文提出一种改进型DB-DTFC策略。首先,为实现转矩和磁链的解耦控制,在两相静止坐标系中对定子电压与转矩和磁链之间的关系进行分析,求解满足控制要求的电压矢量。其次,设计电流和磁链观测器补偿数字控制系统的延时。再次,采用基于4个非零电压矢量的空间矢量脉宽调制(SVPWM)技术,抑制相电流的3次谐波分量。实验结果表明,该策略计算简便,抑制了转矩和磁链脉动,降低了3次谐波电流,提升了控制系统动稳态性能。

改进的同步磁阻电机模型预测转矩控制

针对同步磁阻电机模型预测转矩控制转矩脉动大且受电感参数影响大的问题,提出一种改进的同步磁阻电机模型预测转矩控制方法。利用带遗忘因子的递推最小二乘法对电感参数进行辨识,将辨识得到的电感参数用于模型预测转矩控制中,可提高模型预测控制中数学模型的准确性、减少电感参数变化对模型预测转矩控制性能的影响。引入离散空间矢量调制技术,该技术通过合成大量的虚拟矢量提高系统的稳态性能,同时提出一种电压矢量选择简化方法,避免计算全部电压矢量,可减少计算量。仿真结果表明,该方法转矩与磁链脉动小,具有良好的动稳态性能。

基于SVPWM的PMSM模糊PI-DTC控制研究

为了解决在直接转矩控制(DTC)下永磁同步电机(PMSM)出现的转矩波动大、定子磁链和电流失真严重等问题,提出基于空间电压矢量控制的改进型PMSM模糊PI-DTC控制方法。用电压空间矢量脉宽调制(SVPWM)代替传统DTC的开关表搜索模块,并对PI调节器引入模糊规则在线整定参数,从而得到合适的空间电压矢量,进一步改善电机性能。仿真结果表明:基于SVPWM的PMSM模糊PI-DTC控制技术使得电机启动转矩增大到28.97 N·m,电机启动速度更快,上升时刻缩短,转速跟踪的超调量减为0.51%,极大地提高了跟踪精度,并能显著改善电流畸变和抑制转矩脉动。

扩展卡尔曼滤波参数辨识下永磁同步电机模型预测转矩控制

为了提高模型预测转矩控制的稳态性能,提出一种空间矢量脉宽调制(SVPWM)策略下的无差拍模型预测转矩控制。针对定子电阻与电感对无差拍算法控制效果的重要影响,使用扩展卡尔曼滤波器对模型中的定子电阻、电感参数同时进行在线辨识,以提升算法的参数鲁棒性。首先,对电磁转矩和定子磁链幅值使用无差拍控制,解出两相旋转坐标系下的参考电压矢量,并送入SVPWM进行调制,从而有效抑制了转矩脉动;然后,推导出定子电阻与电感出现不可抗力误差时,dq轴输出电压存在严重偏离理想值的问题;最后,使用扩展卡尔曼滤波器对模型中的电感和电阻参数同时进行在线辨识,并将辨识结果实时反馈至模型中。通过仿真和实验将所提算法的稳态性能、动态性能及参数鲁棒性进行了对比分析,从而证实了所提算法的优越性。

THD Reduction for Permanent Magnet Synchronous Motor Using Simulated Annealing

Any nonlinear behavior of the system is analyzed by a useful way of Total Harmonic Distortion(THD)technique.Reduced THD achieves lower peak current,higher efficiency and longer equipment life span.Simulated annealing(SA)is applied due to the effectiveness of locating solutions that are close to ideal and to challenge large-scale combinatorial optimization for Permanent Magnet Synchronous Machine(PMSM).The parameters of direct torque controllers(DTC)for the drive are automatically adjusted by the optimization algorithm.Advantages of the PI-Fuzzy-SA algorithm are retained when used together.It also improves the rate of system convergence.Speed response improvement and har-monic reduction is achieved with SA-based DTC for PMSM.This mechanism is known to be faster than other algorithms.Also,it is observed that as compared to other algorithms,the projected algorithm yields a reduced total harmonic distor-tion.As a result of the employment of Space Vector Modulation(SVM)techni-que,the system is resistant to changes in motor specifications and load torque.Through MATLAB&Simulink simulation,the experiment is done and the per-formance is calculated for the controller.

永磁同步电机的复叠式螺旋滑模控制策略研究

使用矢量控制、直接转矩控制(DTC)等传统算法对永磁同步电机(PMSM)控制存在系统抖振大、电机参数依赖性强、鲁棒性弱、电机转速和转矩动态响应慢等问题,提出了基于复叠式螺旋滑模控制(CSSMC)的PMSM控制策略。保留了传统DTC的基本结构,即转速控制器、磁链、转矩调节器3部分主体结构,新型控制系统转速环采用CSSMC控制代替传统PI控制,转矩磁链环采用超螺旋滑模控制(STSMC)代替传统滞环控制的DTC控制算法,该控制算法输出信号为dq轴电压可以结合空间矢量调制来对PMSM进行控制。使转速能够快速响应到达理想转速,拥有更小的超调量,且提高了系统的抗干扰性和鲁棒性,同时降低了电磁转矩、磁链的脉动。最后,通过仿真和实验验证所提控制策略的有效性和优越性。

The use of feld programmable gate array(FPGA)in direct torque control of induction motor

In this paper, the feasibility of embedding the direct torque control （DTC） of an induction machine into field programmable gate arrays （FPGA） is investigated. DTC of an induction machine is simulated in a MATLAB/Simulink environment using a Xilinx system generator. The resulting design has a flexible and modular structure where the designer can customize the hardware blocks by changing the number of inputs, outputs, and algorithm when it is compared to the designs implemented using classical microcontrollers and digital signal processors. With its flexibility, other control algorithms can easily be programmed and embedded into the FPGA. The above system has been implemented on Xilinx Spartan 3A DSP FPGA controller. Simulation and experimentation have been performed to prove the validity of the proposed methodology.

改进的异步电机全速域直接转矩滑模控制仿真研究

针对传统牵引异步电机直接转矩控制系统存在转矩脉动大、开关频率不固定以及定子磁链观测器准确度对控制性能有较大的影响等问题。设计了一种新型的滑模控制器,并与空间矢量脉宽调制技术相结合,保证系统在交流调速过程中转矩和磁链能够快速且准确地达到期望值。仿真结果表明:该控制策略满足牵引电机在全速域范围内实现电磁转矩的平稳调节,同时在一定程度上降低了转矩谐波含量,保证了电机运行性能的稳定性。

Robust SVM-direct torque control of induction motor based on sliding mode controller and sliding mode observer

This paper proposes a design of control and estimation strategy for induction motor based on the variable structure approach.It describes a coupling of sliding mode direct torque control(DTC)with sliding mode flux and speed observer.This algorithm uses direct torque control basics and the sliding mode approach.A robust electromagnetic torque and flux controllers are designed to overcome the conventional SVM-DTC draw・backs and to ensure fast response and full reference tracking with desired dynamic behavior and low ripple level.The sliding mode controller is used to generate reference voltages in stationary frame and give them to the controlled motor after modulation by a space vector modulation(SVM)inverter.The second aim of this paper is to design a sliding mode speed/flux observer which can improve the control performances by using a sensorless algorithm to get an accurate estimation,and consequently,increase the reliability of the system and decrease the cost of using sensors.The effectiveness of the whole composed control algorithm is investigated in different robustness tests with simulation using Matlab/Simulink and verified by real time experimental implementation based on dS pace 1104 board.

基于SMC和最优电流矢量的无刷直流电机矢量控制

传统无刷直流电机运行时存在启动抖动明显、转矩脉动大等问题,为解决这些问题,提出采用SVPWM空间矢量脉宽调制策略,运用滑模控制替代转速环PI控制,同时在q轴电流环注入最优电流矢量控制方案。通过搭建仿真模型及仿真结果分析可知,相对传统控制策略能够有效降低启动超调、抑制换相转矩脉动和提高动态响应能力。

基于超扭曲滑模控制和最优电流矢量的无刷电机矢量控制

传统无刷直流电机运行时转速环易受内外参数变化的影响,存在换相转矩脉动大等问题。为解决这些问题,使用SVPWM空间矢量脉宽调制替代PWM调制,并提出转速环采用快速超扭曲滑模控制替代转PI控制、同时在q轴电流注入最优电流矢量的控制方案。通过搭建仿真模型及仿真结果分析可知,相对传统控制策略,此法能够有效降低启动超调、提高动态响应能力、抑制换相转矩脉动。

Research on a direct torque control for an electrically excited synchronous motor drive with low ripple in flux and torque

The electrically excited synchronous motor(ESM)has typically small synchronous inductance values and quite low transient values because of the damper windings mounted on the rotor.Therefore,the torque and stator flux linkage ripples are high in the direct torque control(DTC)drive of the ESM with a torque and flux linkage hysteresis controller(basic DTC).A DTC scheme with space vector modulation(SVM)for the ESM was investigated in this paper.It is based on the compensation of the stator flux link-age vector error using the space vector modulation in order to decrease the torque and flux linkage ripples and produce fixed switching frequency under the principle that the torque is controlled by the torque angle in the ESM.Compared with the basic DTC,the results of the simulation and experiment show that the torque and flux linkage ripples are reduced,the maximum current value is decreased during the startup,and the current distortion is much smaller in the steady-state under the SVM-DTC.The field-weakening control is incorporated with the SVM-DTC successfully.

一种新型的感应电动机直接转矩控制

提出了一种新型的感应电动机直接转矩控制方法,采用空间矢量调制方式生成逆变器开关控制信号,从而有效减小转矩、磁链和电流的脉动。与其他基于空间电压矢量调制的直接转矩控制方法不同,定子磁链幅值与转矩控制器的设计基于变结构控制理论,具有实现简单、鲁棒性强的特点。理论分析证明了定子磁链幅值与转矩控制的渐近稳定性。仿真和实验结果表明了所提方法具有良好的动静态性能。

基于空间矢量调制的直接转矩控制算法研究

针对传统的直接转矩控制由于采用滞环比较器对磁链和转矩进行直接控制,导致出现开关频率不恒定,磁链和转矩脉动大的问题,提出一种基于空间矢量调制的直接转矩控制方法。根据感应电机的数学模型,建立磁链、转矩双闭环PI控制回路。直接以磁链和转矩作为控制量,采用空间电压矢量调制策略。该方法具有矢量控制连续平滑和直接转矩控制快速响应的特性。仿真和实验结果表明,相对于传统的直接转矩控制,基于空间矢量调制的直接转矩控制方案的开关频率恒定,大大减小了转矩脉动,改善了电流和磁链波形,使系统具有良好的动、静态性能,验证了该方法的可行性和有效性。

一种基于转矩角的永磁同步电机直接转矩控制

针对电动汽车用永磁同步电机,提出一种基于转矩角的直接转矩控制策略,并研究了其中磁链与转矩角的限幅要求。所述方法以电机转矩角控制为出发点,利用转矩闭环调节直接得到所发电压矢量幅值,根据定子磁链闭环调节并结合转矩角前馈调整所发电压矢量角度,并通过空间矢量调制得到驱动信号,同时对转矩角实时观测和限制,以保证电机稳定运行。该方法不仅具有对电感参数变化不敏感和鲁棒性较强的优点,而且控制结构简单。实验结果表明该方法有效、可行。