Artificial intelligence-based speed control of DTC induction motor drives—A comparative study

The design of the speed controller greatly affects the performance of an electric drive. A common strategy to control an induction machine is to use direct torque control combined with a PI speed controller. These schemes require proper and continuous tuning and therefore adaptive controllers are proposed to replace conventional PI controllers to improve the drive's performance. This paper presents a comparison between four different speed controller design strategies based on artificial intelligence techniques; two are based on tuning of conventional PI controllers, the third makes use of a fuzzy logic controller and the last is based on hybrid fuzzy sliding mode control theory. To provide a numerical comparison between different controllers, a performance index based on speed error is assigned. All methods are applied to the direct torque control scheme and each control strategy has been tested for its robustness and disturbance rejection ability.     

Variable-structure torque control of induction motors using space vector modulation

Compared with field orient control (FOC), direct torque control (DTC) is known to provide fast and robust response for induction motors. However, while offering high dynamic performance, classical DTC produces notable torque, flux, and current ripples, and operates with a variable inverter switching frequency. In this paper, a novel torque control scheme for induction motors is proposed. The stator flux and the electrical torque are directly controlled by variable-structure controllers, and stator voltage vectors calculated by the variable-structure controllers are applied to the motor by means of space vector modulation. The proposed scheme therefore provides smooth, fast and robust regulations of the electrical torque and the stator flux. Moreover, the implementation of the scheme is simple. Theoretical analysis shows the asymptotical convergence of electrical torque and stator flux tracking. Simulation and experimental results are provided to evaluate the performance of the proposed scheme.     

改进滞环比较器的永磁同步电动机直接转矩控制

在研究了永磁同步电动机直接转矩控制基本原理的基础上，分析了直接转矩控制方案的特点及不足。理论分析结合仿真均表明。对称的磁链滞环调节使转矩波动较大且超出转矩滞环的宽度，将磁链滞环的宽度设得很窄时，可以减小这种波动，但逆变器的开关频率随之增大。本文在分析这种波动产生原因的基础上，提出对滞环比较器进行不对称上下限的设置以抑制转矩较大的波动和降低逆变器的开关频率。仿真结果表明，该方法使得转矩波动限制在要求内，逆变器的开关频率降低。得到了较好的转矩控制效果。     

五电平拓扑下开关磁阻电机直接瞬时转矩控制

针对开关磁阻电机转矩脉动,提出开关磁阻电动机五电平驱动拓扑结构和滞环控制策略.研究和分析五电平拓扑的五电平导通原理,并与不对称半桥驱动电路三电平导通进行比较.结合开关磁阻电机绕组导通和直接瞬时转矩控制原理,设计五电平驱动下开关磁阻电机直接瞬时转矩滞环控制策略,并且进行仿真实验.仿真结果证实与不对称半桥电路相比,五电平拓...     

感应电机磁链和转矩的非奇异终端滑模控制

针对直接转矩控制技术以容差形式的Bang-Bang控制模式给系统的稳态运行带来的转矩脉动大、电流谐波成分重、定子磁链轨迹畸变等问题,将非奇异终端滑模控制应用到了转矩和磁链控制中.为了提高传统滑模控制的收敛性,分别独立设计了转矩控制器和磁链控制器的非奇异终端滑模平面.转矩控制器和磁链控制器由等效控制项和非线性切换项组成,非线性切换项中的符号函数sgn(S)通过积分作用削弱了控制量的抖振.仿真结果表明,非奇异终端滑模变结构直接转矩控制具有动态响应快、转矩波动和转速波动小、鲁棒性强、低"抖振"的特点.     

基于转矩预测控制的无刷双馈电机直接转矩控制系统

在研究无刷双馈电机直接转矩控制调速系统的基础上,针对无刷双馈电机直接转矩控制转矩脉动大的问题,提出了适用于该种电机的转矩预测法.仿真结果表明,该方法能有效地减小转矩脉动、改善定子电流波形,具有良好的动、静态性能.     

基于参考磁链矢量计算的PMSM直接转矩控制

为了减小传统直接转矩控制中较大的转矩和磁链波动,并使逆变器开关频率保持恒定,研究了一种基于参考磁链矢量计算的永磁同步电机直接转矩控制方法。从定子磁链矢量的变化所反映出的对转矩和磁链的控制作用考虑,对基于参考磁链矢量计算的直接转矩控制的原理和结构进行了详细地分析和论述。在此基础上,通过转矩方程局部线性化来获取转矩环的控制模型,在线性化过程中的误差进行分析的基础上,研究了转矩环PI控制器的参数设计方法。仿真和实验结果验证了所研究控制方法的可行性和有效性。     

Sliding mode approach applied to sensorless direct torque control of cage asynchronous motor via multi-level inverter

To improve the robustness and performance of the dynamic response of a cage asynchronous motor, a direct torque control (DTC) based on sliding mode control (SMC) is adopted to replace traditional proportional-integral (PI) and hysteresis comparators. The combination of the proposed strategy with sinusoidal pulse width modulation (SPWM) applied to a three-level neutral point clamped (NPC) inverter brings many advantages such as a reduction in harmonics, and precise and rapid tracking of the references. Simulations are performed for a three-level inverter with SM-DTC, a two-level inverter with SM-DTC and the three-level inverter with PI-DTC-SPWM. The results show that the SM-DTC method achieves better performance in terms of reference tracking, while adoption of the threelevel inverter topology can effectively reduce the ripples. Applying the SM-DTC to the three-level inverter presents the best solution for achieving efficient and robust control. In addition, the use of a sliding mode speed estimator eliminates the mechanical sensor and this increases the reliability of the system.     

Direct torque control of doubly fedinduction motor using three-level NPCinverter

This article presents the direct torque control (DTC) strategy for the doubly fed induction motor (DFIM) connectedto two three-level voltage source inverters (3LVSIs) with neutral point clamped (NPC) structure. This control methodallows to reduce the torque and flux ripples as well as to optimize the total harmonic distortion (THD) of motorcurrents. The use of 3LVSI increases the number of generated voltage, which allows improving the quality of itswaveform 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 interms of torque and flux behavior, compared to conventional DTC.     

直接转矩控制系统中减小转矩脉动方案的比较

采用离散空间矢量调制(DSVM)和转矩预测技术减小感应电机直接转矩控制系统(DTC)低速时的转矩脉动,为了系统实现时编程简单,对DSVM的开关表进行了优化,将每个采样周期分为3个相等的时间段,每个时间段中作用一个电压矢量,采用单一非零电压矢量与零电压矢量的组合来代替非零电压矢量与非零电压矢量的组合,简化了开关表,降低了开关频率,保证了低速时的带载能力.在此基础上将DSVM与转矩预测进行了实验对比.实验结果表明:与转矩预测相比,开关表优化后的DSVM在减小低速时的转矩脉动,改善电流和磁链波形方面取得了更好的控制效果,且保持了转矩动态响应快的优点.     

基于定子磁链定向的直接转矩控制

把直接转矩控制 (DTC)与定子磁链定向矢量控制 (SFOVC)相结合 ,利用DTC中电压矢量的空间位置角推导出SFOVC中的磁链定向角 ,然后根据旋转坐标系中的d轴和 q轴电流分量建立定子磁链估计的数学模型。使DTC中磁链的估计更简便易行也要精确。同时给出了仿真实验结果 ,由仿真结果可知该方法是正确可行的。     

基于变结构PI的空间矢量直接转矩控制系统研究

直接转矩控制技术以结构简单、动态响应快、鲁棒性强等优点受到国内外学者的广泛关注,但是传统直接转矩控制也存在转矩波动大、低速性能差等不足.将空间矢量调制技术(SVM)与直接转矩控制相结合为解决这一问题开辟了新的途径,然而采用PI控制的空间矢量转矩控制系统对系统外部扰动、参数摄动的鲁棒性较差.提出一种基于变结构PI的直接转...     

Robust sliding mode control and flux observer for induction motor using singular perturbation

This paper proposes a sequential methodology for designing a robust adaptive sliding mode observer for an induction motor drive using a two-time-scale approach. This approach is based on the singular perturbation theory. The two-time-scale decomposition of the original system of the observer error dynamics into separate slow and fast subsystems permits a simple design and sequential determination of the observer gains. In the proposed method, the stator currents and rotor flux are observed on the stationary reference frame using the sliding mode concept. The control algorithm is based on the indirect field oriented sliding mode control with an on-line adaptation of the rotor resistance to keep the machine field oriented. The control–observer scheme seeks to provide an asymptotic tracking of speed and rotor flux in spite of the presence of an uncertain load torque and an unknown value of rotor resistance. The validity for practical implementation has been verified through computer simulations.     

基于SVPWM五相感应电机直接转矩控制研究

针对感应电机直接转矩控制(DTC)采用开关表的滞环方法时,存在电流和转矩脉动等问题,提出在DTC中应用空间矢量脉宽调制(SVPWM)的方法。根据五相感应电机模型和DTC基本原理,推导出参考电压矢量。分析了五相逆变器的空间电压矢量,并从中选取出22个有效电压矢量,根据最近四矢量SVPWM算法,计算出第k扇区中工作电压矢量的作用时间。建立了基于双DSP控制的实验系统,实验结果表明,该方法减小了电流和转矩脉动,具有良好的稳态和动态性能。     

无刷直流电机控制系统中PWM调制方式对换相转矩脉动的影响

介绍了无刷直流电机控制系统中的四种PWM调制方式，详细分析了四种不同的调制方式对无刷直流电机换相转矩脉动的影响。通过理论推导，证明当控制系统采用pwm_on型调制方式时无刷直流电机在换相过程中的转矩脉动最小，实验结果证明了所结论的正确性和实用性。     

柔性平动式啮合电机动态分析与转矩控制

介绍了一种柔性机构平动式啮合电机结构和运行原理.该电机利用4组磁极间的磁场力驱动转子在柔性机构约束下绕定子轴线做圆周平动,进而直接带动摆线机构输出低速大扭矩.针对该电机特点,依据磁共能原理,采用动态分析方法建立了电机的磁场和转矩特性模型,分别运用解析方法和有限元方法计算了电机的电感特性;结合直接转矩控制原理推导出了柔性平动式啮合电机的转矩控制算法.设计了物理样机和控制系统,通过仿真和物理样机实验证明了直接转矩控制较开关控制方法降低了电机的振动,控制转速波动在10%以内.理论分析和实验结果均表明该转矩控制方法具有较高的可行性和实用性.     

SRM积分滑模变结构与神经网络补偿控制

针对开关磁阻电机非线性动态特性不易控制的缺点,提出了一种积分型滑模变结构与神经网络补偿相结合的复合控制策略.应用一个具有积分型式的滑模切换面的变结构控制器,使用积分补偿技巧降低系统的振动与稳态误差.为减小滑模面的抖动,引入神经网络补偿控制环节.建立滑模变结构控制的数学模型,并给出神经网络补偿滑模面抖动的控制律表达式.利...     

异步电机滑模直接转矩控制器的设计

阐述了采用滑模控制器三点式直接转矩控制逆变器的原理、特点及微机控制方案,建立了系统的数学模型,并给出仿真波形。     

抑制PMSM周期性转矩脉动的迭代学习方法

为了抑制永磁同步电机高性能伺服应用中的低速转矩脉动,在探讨转矩脉动传统抑制方法的基础上,分析并指出主要成分的周期特性,提出永磁同步电机恒压频比控制中通过迭代学习控制抑制周期性转矩脉动的方法,通过在线学习补偿电机控制电压来抑制转矩脉动,设计了控制器并作了收敛性分析.仿真结果表明:迭代学习快速收敛,可有效减小转矩脉动,转矩...     

感应电机直接转矩控制系统

为了确定影响感应电机直接转矩控制系统稳态性能的主要因素,使用自己开发的仿真软件包进行了仿真实验分析,指出了定子电阻、磁链滞环容差和转矩滞环容差是影响感应电机直接转矩控制系统性能的三个主要因素.定子电阻主要对磁链轨迹影响较大,磁链滞环容差和转矩滞环容差主要影响定子电流谐波和电机转矩,并提出了一些补偿措施.这些结论为进一步改进系统性能提供了一些依据.