基于定子电阻观测器的永磁同步电动机滑模变结构直接转矩控制研究

传统的永磁同步电动机直接转矩控制系统存在着转矩和磁链脉动大、低速运行时难以精确控制以及因转矩脉动引起的高频噪声等问题。为解决这些问题,通过定子电阻观测器,利用定子电流与参考定子电流之差来跟踪定子电阻的变化,实现定子电阻的实时估算;用转矩和磁链滑模变结构控制器来替代传统直接转矩控制中的滞环控制器。仿真结果表明,基于定子电阻观测器的永磁同步电动机滑模变结构直接转矩控制系统具有较小的转矩、磁链脉动和快速的动态响应性能。

基于DSP的矩阵变换器直接转矩控制的研究

提出了一种适用于矩阵变换器供电的异步电动机调速系统的组合控制策略,同时实现了矩阵变换器的空间矢量调制和异步电动机的定子磁场定向直接转矩控制。实验结果表明,使用该控制策略的调速系统有良好的动态性能。

同步电机直接转矩控制SVM法的研究

在交流调速系统中,同步电机由于其功率因数高、变频器容量小、转动惯量小等优点,越来越多地被应用在工农业生产中.直接转矩控制是继矢量控制之后发展起来的一种新型的交流调速技术,具有控制结构简单、转矩响应迅速、对电机内部参数依赖少和易于数字化等优点。把直接转矩控制技术应用于同步电机之中,具有理论价值和应用前景。文章以直接转矩控制策略为中心,把基于空间电压矢量PWM调制的方法引入传统的直接转矩控制中进行改进和仿真,结果表明,这种方法转速响应快,能够较好地减小磁链和转矩脉动.

Design and Development of the DTC Induction Motor Drive for Electric Vehicle

The design and development of the traction controller for electric vehicle is introduced, which is based on the induction motor. This drive is developed by using a digital signal processor at low cost and carried out with the module design concept of both software and hardware. Nevertheless, a scheme of the sensorless direct torque control is based on the developed hardware, of which the feasibility is tested by a trial program. Additionally, both the interface function of the drive hardware and the feasibility of its software are proved to be good by the trail programs. A test motor can run about 18?r/min by a variable frequency program with the space vector pulse width modulation technology, of which the torque is visible pulsatile. In this presentation, based on the theoretical approach, the sensorless torque control is to be studied and applied to electric vehicles, of which the quick, smooth and stable torque response is emphasized because it quite benefits improving the drive performance of electric vehicles.

Genetic algorithm and particle swarm optimization tuned fuzzy PID controller on direct torque control of dual star induction motor

This study presents analysis, control and comparison of three hybrid approaches for the direct torque control (DTC) of the dual star induction motor (DSIM) drive. Its objective consists of combining three different heuristic optimization techniques including PID-PSO, Fuzzy-PSO and GA-PSO to improve the DSIM speed controlled loop behavior. The GA and PSO algorithms are developed and implemented into MATLAB. As a result, fuzzy-PSO is the most appropriate scheme. The main performance of fuzzy-PSO is reducing high torque ripples, improving rise time and avoiding disturbances that affect the drive performance.

Fuzzy-second order sliding mode control optimized by genetic algorithm applied in direct torque control of dual star induction motor

The direct torque control of the dual star induction motor(DTC-DSIM) using conventional PI controllers is characterized by unsatisfactory performance, such as high ripples of torque and flux, and sensitivity to parametric variations. Among the most evoked control strategies adopted in this field to overcome these drawbacks presented in classical drive, it is worth mentioning the use of the second order sliding mode control(SOSMC) based on the super twisting algorithm(STA) combined with the fuzzy logic control(FSOSMC). In order to realize the optimal control performance, the FSOSMC parameters are adjusted using an optimization algorithm based on the genetic algorithm(GA). The performances of the envisaged control scheme, called G-FSOSMC, are investigated against G-SOSMC, G-PI and BBO-FSOSMC algorithms. The proposed controller scheme is efficient in reducing the torque and flux ripples, and successfully suppresses chattering. The effects of parametric uncertainties do not affect system performance.

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.

A novel fuzzy logic direct torque controller for a permanent magnet synchronous motor with a field programmable gate array

A high-performance digital servo system built on the platform of a field programmable gate array (FPGA),a fully digitized hardware design scheme of a direct torque control (DTC) and a low speed permanent magnet synchronous motor (PMSM) is proposed. The DTC strategy of PMSM is described with Verilog hardware description language and is employed on-chip FPGA in accordance with the electronic design automation design methodology. Due to large torque ripples in low speed PMSM,the hysteresis controller in a conventional PMSM DTC was replaced by a fuzzy controller. This FPGA scheme integrates the direct torque controller strategy,the time speed measurement algorithm,the fuzzy regulating technique and the space vector pulse width modulation principle. Experimental results indicate the fuzzy controller can provide a controllable speed at 20 r min-1 and torque at 330 N m with satisfactory dynamic and static performance. Furthermore,the results show that this new control strategy decreases the torque ripple drastically and enhances control performance.

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.

Simulation study on the starting characteristics of a kind of improved direct torque control system

Analyzed working principle and starting process of asynchronous motor direct torque control system. In order to solve the problem of serious fluctuation of starting current in traditional control scheme, the author puts forward a new kind of starting method which can limit voltage value to achieve the goal of reducing fluctuation of the current by increasing zero voltage vectors during the stage of starting. The author has also carried on simulation study on the system, and the result of simulation study shows that this method is effectual.

Comparative Study of the DTC-IM Speed Controller Based on Artificial Intelligence

Recently, artificial intelligence technique is increasingly receiving attention in solving complex and practical problem and they are widely applying in electrical machine domain. The authors consider also the direct torque control （DTC） as an alternative to conventional methods of control by pulse width modulation （PWM） and by Field oriented control （FOC）, so the application of the DTC based on artificial intelligence can show more advantages and simplified control algorithms with high performance. For this reason, the objectives of this paper can be divided into two parts, the first part is to apply neural networks and fuzzy logic techniques to the DTC control in the presence of a loop speed control comparing to the conventional regulators （as PI） to show the feasibility of these approaches, the second part is to further improve the performance of the neural network by using a neural-fuzzy regulator which combine the advantages of two techniques. Simulation results confirm the validity of the proposed techniques.

An Improved Proportional Integral Estimator of the Stator Resistance for a Direct Torque Controlled Induction Motor

In this paper, an improved PI （proportional integral） stator resistance estimation for a DTC （direct torque controlled） induction motor is proposed. This estimation method is based on an on-line stator resistance correction regarding the variations of the stator current estimation error. In fact, the input variable of the P1 estimator is the stator current estimation error. The main idea is to tune accurately the stator resistance value relatively to the evolution of the stator current estimation error gradient to avoid the drive instability and ensure the tracking of the actual value of the stator resistance. But there is an unavoidable steady state error between the filtered stator current modulus and its estimated value from the dq model of the machine which is due to pseudo random commutations of the inverter switches. This may deteriorate the performance of the proposed fuzzy stator resistance estimator. An offset has been introduced in order to overcome this problem, for different speed command values and load torques. Simulation results show that the proposed estimator was able to successfully track the actual value of the stator resistance lbr different operating conditions.

Relevance of the P ＆ O MPPT Technique in an Original PV-Powered Water Pumping Application

Many papers exploiting the various MPPT （maximum power point tracking） techniques in PV （photovoltaic） applications, from the simple to the most complicated, can be found in literature. However, these techniques may not always be easy to implement in industrial applications. The main challenge of this paper is to model and implement the P ＆ O （perturb and observe） algorithm in a low-cost PV-powered pumping system. To that end, a comparative investigation of the performance characteristics of the most popular MPPT methods, such as FOCV （fractional open circuit voltage）, FSCC （fractional short circuit current）, FLC （fuzzy logic control）, ANN （artificial neural network） and INC （incremental conductance） is presented. This analysis is helpful to highlight the relevance of the P ＆ O technique taking better account of complexity, difficulty of implementation and cost considerations in water pumping applications. The targeted PV-powered pumping system is based on a single-phase induction motor supplied by a three-phase inverter controlled by the DTC （direct torque control） technique. This stand-alone PV system is dedicated to water pumping, especially in rural areas that have no access to national grids but have sufficient amount of solar radiation. Simulation modeling （Matlab/Simulink） and experimental results are presented to demonstrate the relevance of the system.

A New Scheme to Direct Torque Control of Interior Permanent Magnet Synchronous Machine Drives for Constant Inverter Switching Frequency and Low Torque Ripple

DTC （direct torque control） can produce quick and robust response, but it has the problems of large torque ripples and inconstant inverter switching frequency. This paper introduces a modified direct torque control based on the SVM （space vector modulation） for IPMSM （interior permanent magnet synchronous motor） drive. Two PI （proportional-integral） controllers regulate the flux and torque, respectively, and the inverter is controlled by the SVM technique in the proposed DTC system. Simulation results show that the performance of the proposed DTC system has been improved with respect to the conventional DTC. The DTC system can effectively reduce the flux and torque ripples.

Load Torque Compensator for Model Predictive Direct Current Control in High Power PMSM Drive Systems

The widely used cascade speed and torque controllers have a limited control performance in most high power applications due to the low switching frequency of power electronic converters and the convenience to avoid speed overshoots and oscillations for lifetime considerations. Model Predictive Direct Current Control （MPDCC） leads to an increase of torque control performance taking into account the discrete nature of inverters but temporary offsets and poor responses to load torque variations are still issues in speed control. A load torque estimator is proposed in this paper in order to further improve dynamic behavior. It compensates the load torque influence on the speed control setting a feed forward torque reference value. The benefits are twice; the speed controller reaches the speed reference value without offsets which would need to be compensated by an integrator and a better response to load torque variations is obtained since they are detected and compensated leading to small speed variations. Moreover, the influence of pararneter errors and disturbances has been analyzed and limited so that they play a minor role in operation.

A modified structure internal model robust control method for the integration of active front steering and direct yaw moment control

Taking into account the nonlinearity of vehicle dynamics and the variations of vehicle parameters,the integrated control strategy for active front steering(AFS)and direct yaw control(DYC)that can maintain the performance and robustness is a key issue to be researched.Currently,the H∞method is widely applied to the integrated control of chassis dynamics,but it always sacrifices the performance in order to enhance the stability.The modified structure internal model robust control(MSIMC)obtained by modifying internal model control(IMC)structure is proposed for the integrated control of AFS and DYC to surmount the conflict between performance and robustness.Double lane change(DLC)simulation is developed to compare the performance and the stability of the MSIMC strategy,the PID controller based on the reference vehicle model and the H∞controller.Simulation results show that the PID controller may oscillate and go into instability in severe driving conditions because of large variations of tire parameters,the H∞controller sacrifices the performance in order to enhance the stability,and only the MSIMC controller can both ensure the robustness and the high performance of the integrated control of AFS and DYC.