Direct Torque and Adaptive Flux Sensorless Control of Novel Transverse Flux Permanent Magnet Motors

横向磁通永磁电机在开环无刷直流驱动模式下不可避免存在转矩脉动,但可以通过采用直接转矩控制加以改善。首先分析无刷直流驱动中＂花瓣＂状定子磁链轨迹的形成机理,然后针对传统转矩和磁链双闭环直接转矩控制中的定子磁链给定难的问题,提出了无位置传感器磁链自适应直接转矩控制方案。该方案仅利用定子磁链位置和转矩滞环比较器决定电压矢量,并配合换相补偿以修正定、转子磁链夹角与最佳提前换相角之间的偏差以兼顾高转矩电流比和低转矩脉动。仿真和实验结果证实了该方案的有效性和可行性。

An Observing Method for Flux and Speed with Direct Torque Control

An observing method for stator flux and rotor flux is presented. Based on the proposed flux observing method, a novel speed estimator has been designed. At last, the speed estimator combined with the flux observing is applied in the direct torque control system without speed sensor. The simulation results show that these methods can improve the accuracy of speed observing and the low speed performance of direct torque control system, and strengthen the robustness of system.

Direct Torque Control System and Sensorless Technique of Permanent Magnet Synchronous Motor

The direct torque control theory has achieved great success in the control ofinduction motors. However, in the DTC drive system of Permanent Magnet Synchronous Machine (PMSM)proposed a few years ago, there are many basic theoretical problems that must be clarified. Thispaper describes an investigation about the effect of the zero voltage space vectors in the DTCsystem of PMSM and points out that if using the zero voltage space vectors rationally, not only canthe DTC system be driven successfully but also the torque ripple is reduced and the performance ofthe system is improved. This paper also studies the sensorless technique in the DTC system of PMSMand configures the DTC system of PMSM with sensorless technique including zero voltage spacevectors. Numerical simulations and experimental tests have proved the theory correct. In thecondition of sensor-less, the DTC system of PMSM is wide-rangely speed adjusting, and the ratio ofspeed adjustment is 1: 100.

Application of direct torque control to electric screw presses for speeding up torque response and reducing starting current

Fast response and stable torque output are crucial to the performance of electric screw presses. This paper describes the design of a direct torque control （DTC） system for speeding up torque response and reducing the starting current of electric screw presses and its application to the J58K series of numerical control electric screw presses with a dual-motor drive. The DTC drive system encompasses speed control, torque reference control, and switching frequency control. Comparison of the DTC dual-AC induction motor drive with corresponding AC servo motor drive showed that for the J58K-315 electric screw press, the DTC drive system attains a higher maximum speed （786 r/min） within a shorter time （1.13 s） during a 250 nun stroke and undergoes smaller rise in temperature （42.0 ℃） in the motor after running for 2 h at a 12 min-1 strike frequency than the AC servo motor drive does （751 r/min within 1.19 s, and 50.6 ℃ rise）. Moreover, the DTC AC induction motor drive, with no need for a tachometer or position encoder to feed back the speed or position of the motor shaft, enjoys increased reliability in a strong-shock work environment.

Research on Direct Torque Control System Based on Induction Motor

The mathematic model of direct torque control (DTC) was deduced. Two simulating models based on the MATLAB & SIMULINK were established. The emphasis is focused on study of the performance difference of the DTC system with stator flux hexagon and circle trajectories. The simulation waveforms of flux, torque and current characters with two flux trajectories were given. Experiments were carried out in an AC drive system based on induction motor and two-level inverter. A dual-CPU structure was used and the communication with two CPUs was obtained by a dual-port RAM in this system.

An Improved Stator Flux Observation Method of Permanent Magnet Synchronous Motor

The stator flux and electromagnetic torque observation is the basis of direct torque controlled permanent magnet synchronous motor( PMSM) drive system. However,the traditional stator flux observer based on voltage model is affected by integral initial values and integral drift,that based on current model is affected by the parameters of PMSM,so a new stator flux observation method is proposed based on an improved secondorder generalized integrator( SOGI). Compared to the stator flux observation method based on the conventional SOGI,the proposed method can not only overcome the influence of integral initial values and integral drift,but also completely eliminate the DC offset's influence. Therefore,the observation accuracy of stator flux is further improved. The simulation and experimental results both show that the proposed method has a higher stator flux and electromagnetic torque observation precision.

A novel technology for control of variable speed pumped storage power plant

Variable speed pumped storage machines are used extensively in wind power plant and pumped storage power plant. This paper presents direct torque and flux control(DTFC) of a variable speed pumped storage power plant(VSPSP). By this method both torque and flux have been applied to control the VSPSP. The comparison between VSPSP's control strategies is studied. At the first, a wind turbine with the capacity 2.2 k W and DTFC control strategies simulated then a 250 MW VSPSP is simulated with all of its parts(including electrical, mechanical, hydraulic and its control system) by MATLAB software. In all of simulations, both converters including two-level voltage source converter(2LVSC) and three-level voltage source converter(3LVSC) are applied. The results of applying 2LVSC and 3LVSC are the rapid dynamic responses with better efficiency, reducing the total harmonic distortion(THD) and ripple of rotor torque and flux.

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.

IPMSM的无速度传感器Deadbeat直接转矩控制

提出一种基于模型参考自适应有效磁链观测器的内置式永磁同步电机(IPMSM)无差拍直接转矩控制(DB-DTC)策略。通过引入有效磁链的概念,将电压模型与电流模型级联,构建模型参考自适应有效磁链和转速观测器,观测有效磁链的幅值和相位,进而实现转子位置和转速估计。将有效磁链观测器与DB-DTC相结合,实现IPMSM无速度传感器驱动控制。实验结果表明,该观测器可以在较宽速度范围内准确观测转子位置与速度,驱动系统具有良好的动、静态性能。

磁链分区的磁场增强型永磁电机全速域模型预测直接转矩控制

磁场增强型内置式永磁(flux intensifying interior permanent magnet,FI-IPM)电机的反凸极(L_(q)<L_(d))特性,使得正向d轴电流增强磁场,提高输出转矩的同时,也使得弱磁升速时d轴电流正负交替变化,电流角度变化大,磁链波动大,进而造成转矩脉动大、电流畸变振荡、响应速度慢等问题。针对这些问题,该文提出一种基于磁链分区的磁场增强型内置式永磁电机全速域模型预测直接转矩控制控制策略。根据FI-IPM电机速度运行区域与磁链状态映射关系,构建磁链和转矩预测模型。在此基础上,提出磁链分区控制,引入磁链差值判断增磁和弱磁运行区,并进行磁链补偿,解决不同速度运行域之间切换的震荡和不稳定问题。最后,通过实验验证所提出控制策略的有效性,为该类电机在电驱动系统中的应用提供技术方案。

基于虚拟方波注入的五相永磁同步电机开路故障下直接转矩控制

在传统直接转矩控制(DTC)中,参考磁链往往是一个固定值,这将导致五相永磁同步电机(PMSM)在正常及容错情况下运行时效率不高。为解决该问题,该文提出一种基于虚拟方波注入的DTC(VSWI-DTC)策略。首先,建立五相PMSM在正常和开路故障情况下的数学模型,在同步旋转坐标系中推导出恒定转矩下电流幅值与定子磁链幅值的关系。其次,设计最优定子磁链探测器。通过向定子磁链幅值中注入虚拟方波信号,根据电流幅值的变化情况补偿定子磁链幅值,在线探寻最优定子磁链幅值。最后,与无差拍DTC相结合,实现电机高效率DTC运行。实验结果表明,所提策略不但能保持DTC良好的动态性能,抑制开路故障引起的转矩脉动,而且提高了电机在正常和开路故障情况下的效率。

计及磁链和电流的PMSM DTC系统中功率器件键合线老化监测方法

在闭环控制系统中,基于电参数的功率器件老化监测方法是电力电子可靠性领域的难点之一。以永磁同步电机直接转矩控制系统为例,研究基于磁链相图和电流的功率逆变器中功率器件老化状态的在线监测方法。首先,分析功率器件老化的特征,得到键合线老化引起通态电阻增加的结论;其次,研究得到功率器件键合线老化与磁链相图、直轴电流和三相电流峰值变化的关系,进而提出功率器件键合线老化的监测方法;最后,通过多组仿真实验验证了基于磁链相图和电流的在线监测方法均可实现功率逆变器中功率器件键合线老化状态的在线监测。其中,基于磁链相图的在线监测方法需要系统磁链出现一些波动时才易观测,此时功率器件处于失效状态,该方法并不可取;而基于三相电流的监测方法能够更为精确地监测功率器件老化状况,效果更为优越。

智能跑步机异步电机变频调速直接转矩控制

因智能跑步机控制系统存在延时的问题,导致跑步机的运行损耗高、效率低。为此,提出智能跑步机异步电机变频调速直接转矩控制方法。分析异步电机的变频调速效果,构建跑步机控制约束,将模型预测直接转矩控制算法作为非线性内部控制器的控制算法,估计定子磁链后预测定子磁链和电磁转矩,建立合适的目标函数,并采用末端输出控制法获取定子磁链和电磁转矩参考值,对跑步机系统延时加以补偿,完成智能跑步机异步电机变频调速直接转矩控制。实验结果表明,所提方法控制下的智能跑步机振幅曲线波动最小,电磁转矩在(0.5~1.5)N·m之间,稳定后的运行损耗和运行效率控制在67 W和0.77%左右,可有效减小跑步机的电磁转矩脉动,降低运行损耗,提高运行效率,且具有良好的平稳性。

开关磁阻电机自抗扰无磁链直接转矩控制

针对传统直接转矩控制策略转矩脉动抑制性能弱、调速平稳性差和调速范围窄问题,提出一种基于自抗扰的开关磁阻电机无磁链直接转矩控制。分析传统直接控制转矩策略转矩脉动较大的原因,在此基础上设计了一种无磁链闭环控制方法并且重构了更适应电机运行特性的电压矢量;针对传统自抗扰参数过多难以整定问题,采用线性自抗扰控制器将其代替,提高了控制器的速度、抗扰动能力和鲁棒性。仿真验证结果表明,在不同转速、负载工况下,不仅动态响应性能提升,而且电机转矩脉动得到进一步抑制,电流峰值降低,进而提高了转矩电流比。

刮板输送机智能控制方案的设计

针对刮板输送机控制系统存在动态响应性能差、调速精度低、多电动机功率失衡的问题,将无差拍直接转矩控制技术和环形交叉耦合控制技术引入刮板输送机控制系统中,建立PMSM离散数学模型,预测最优空间电压矢量,利用SVPWM得到对应的逆变器开关序列,进而实现DB-DTFC控制;3个闭环转速给定相互耦合、相互补偿,实现机头机尾多电动机功率平衡;搭建刮板输送机控制系统仿真模型,验证所提控制算法的有效性。结果表明,采用所提控制算法后能提升刮板输送机的动态响应性能和调速精度,可实现多电动机功率平衡,保障刮板输送机安全、连续、平稳运行。

空间矢量调制的永磁同步电机直接转矩控制

提出一种基于空间电压矢量调制的表贴式永磁同步电机直接转矩控制方法。基于表贴式永磁同步电机的数学模型,通过计算在一个控制周期内能同时精确补偿转矩误差和磁链误差的空间电压矢量,得出基于磁链与转矩的无差拍控制方法。相对于传统的永磁同步电机直接转矩控制方法,该方法能够明显减小磁链与转矩脉动,并且保持了传统直接转矩控制中转矩动态响应快的优点。不同于传统的永磁同步电机直接转矩控制方法,该方法由于使用了空间电压矢量调制,系统在不同工况下具有恒定的开关频率。仿真和实验结果验证了所提出方法的正确性和可行性。

基于定子磁链降阶状态观测的永磁同步电机无差拍直接转矩控制系统

针对传统永磁同步电机直接转矩控制中存在的磁链和转矩脉动较大、逆变器开关频率不恒定的缺点。文中提出了一种无差拍的永磁同步电机直接转矩控制方案。在一个控制周期内同时精确补偿了给定磁链幅值与实际磁链幅值、给定转矩幅值与实际转矩幅值的误差,实现了磁链与转矩的无差拍控制。为解决永磁同步电机直接转矩控制系统需要转子的初始位置信息以确定定子磁链的初始值这一问题,本文通过构造定子磁链降阶观测器的方法消除初始磁链误差,使永磁同步电机直接转矩控制系统的运行不依赖转子初始位置信息。最后提出了一种适宜于无差拍直接转矩控制算法和定子磁链降阶观测器的基于转子磁链的转速辨识方法。使整个系统实现无速度传感器运行。

无刷直流电机的磁链自控直接转矩控制

结合无刷直流电机的特点,在分析传统脉宽调制电流控制的基础上,针对现有直接转矩控制中磁链估算和给定困难等问题,提出无刷直流电机的磁链自控直接转矩控制方案。该方案采用转矩滞环单环控制,根据转矩环输出和磁极位置决定施加的电压矢量,以实现磁链的自控制,省掉了磁链闭环,简化了系统。同时,系统能够有效地抑制非理想反电势和低速时电流换相引起的转矩波动。为准确估算电机转矩,在两相静止坐标系下采用滑模观测器观测电机反电势,进而计算转矩。仿真和实验结果表明,磁链自控直接转矩控制系统具有良好的转矩动态响应和稳态性能。

直接转矩控制的发展与展望

文章介绍了直接转矩控制 (DTC)发展的历史、现状 ,重点介绍了它在现阶段发展的情况 。

计及逆变器电压输出限制的感应电机无差拍直接转矩控制

提出一种新的感应电机无差拍直接转矩控制方法。基于感应电机的离散化模型,在定子磁场定向坐标系中,以定子和转子磁链为状态变量,导出了空间矢量无差拍直接转矩控制的电压控制律。采用一种图形化的分析方法,直观地揭示了无差拍直接转矩控制电压矢量解的物理意义。研究了在电压源逆变器输出电压受限条件下,无差拍直接转矩控制的设计与实现问题。针对电机的不同运行工况要求,给出了3种可选的电压矢量解的实现方案。在理论分析的基础上,对控制算法进行了仿真和实验测试,结果表明调速系统的转矩和磁链动态响应快,控制性能优良。