scholarly journals Direct torque control of IM using PID controller

Author(s):  
Ali Najim Abdullah ◽  
Mohammed Hasan Ali

Direct torque control "DTC" technique is one of a high performance control system of an AC motor drive, which was proposed after the vector oriented control scheme during the resent 25 years. It has been developed rapidly for its concise system scheme, transient and dynamic performance. The DTC mechanism consists of voltage vector selection table, two hysteresis comparators and two estimators one for stator flux and another for electromagnetic torque. DTC is directly control torque and flux by using Voltage Source Inverter VSI, space vector and stator flux orientation and indirect speed regulated. A several control techniques can be used for improving the torque and flux performance. In this paper, the DTC with Proportional-Integral-Derivative (PID) controller used to improve the starting and dynamic performance of asynchronous motor AM, which gives good torque and flux response, best speed control and also minimize the unacceptable torque ripple. The mathematical model of DTC with PID controller of 3-phase induction motor IM are simulated under Matlab-Simulink. Therefore, the DTC based on PID controller has good performance of IM compared to classical DTC for starting, running state and also during change in load.

2015 ◽  
Vol 713-715 ◽  
pp. 814-819
Author(s):  
Li Ping Zhang ◽  
Xu Guang Xin ◽  
Wei Ya Wang ◽  
Hai Feng Wu

The direct torque control (DTC) system of the traditional asynchronous motor has many disadvantages, such as complex modeling and large amount of calculation, In order to improve the dynamic performance of the DTC system of the asynchronous motor, a direct torque control system is put forward. It uses space vector analysis method to calculate electromagnetic torque and stator flux linkage of asynchronous motor directly, follows the change of the stator flux linkage and torque, omits the complicated calculation, reduces the dependence on motor parameters. The simulation model of the DTC system of the asynchronous motor was established using SIMULINK software package. The feasibility of method is proved in theory, The results of simulation show that the modeling and simulation of the system has good static and dynamic performance, control precision of the system is higher, the stability is better.


Electronics ◽  
2019 ◽  
Vol 8 (7) ◽  
pp. 820 ◽  
Author(s):  
Ibrahim Mohd Alsofyani ◽  
Kyo-Beum Lee

Constant-frequency torque regulator–based direct torque control (CFTR-DTC) provides an attractive and powerful control strategy for induction and permanent-magnet motors. However, this scheme has two major issues: A sector-flux droop at low speed and poor torque dynamic performance. To improve the performance of this control method, interleaving triangular carriers are used to replace the single carrier in the CFTR controller to increase the duty voltage cycles and reduce the flux droop. However, this method causes an increase in the motor torque ripple. Hence, in this work, different discrete steps when generating the interleaving carriers in CFTR-DTC of an induction machine are compared. The comparison involves the investigation of the torque dynamic performance and torque and stator flux ripples. The effectiveness of the proposed CFTR-DTC with various discrete interleaving-carriers is validated through simulation and experimental results.


Author(s):  
Zineb Mekrini ◽  
Seddik Bri

<p><span>This article investigates solution for the biggest problem of the Direct Torque Control on the asynchronous machine to have the high dynamic performance with very simple hysteresis control scheme. The Conventional Direct Torque Control (CDTC) suffers from some drawbacks such as high current, flux and torque ripple, as well as flux control at very low speed. In this paper, we propose an intelligent approach to improve the direct torque control of induction machine which is an artificial neural networks control. The principle, the numerical procedure and the performances of this method are presented.  Simulations results show that the proposed ANN-DTC strategy effectively reduces the torque and flux ripples at low switching frequency, compared with Fuzzy Logic DTC and The Conventional DTC.</span></p>


Author(s):  
Nabilah Aisyah ◽  
Maaspaliza Azri ◽  
Auzani Jidin ◽  
M. Z. Aihsan ◽  
MHN Talib

<span>Since the early 1980s, fast torque dynamic control has been a subject of research in AC drives. To achieve superior torque dynamic control, two major techniques are used, namely Field Oriented Control (FOC) and Direct Torque Control (DTC), spurred on by rapid advances in embedded computing systems. Both approaches employ the space vector modulation (SVM) technique to perform the voltage source inverter into over modulation region for producing the fastest torque dynamic response. However, the motor current tends to increase beyond its limit (which can damage the power switches) during the torque dynamic condition, due to inappropriate flux level (i.e. at rated stator flux). Moreover, the torque dynamic response will be slower, particularly at high speed operations since the increase of stator flux will produce negative torque slopes more often. The proposed research aims to formulate an optimal switching modulator and produce the fastest torque dynamic response. In formulating the optimal switching modulator, the effects of selecting different voltage vectors on torque dynamic responses will be investigated. With greater number of voltage vectors offered in dual inverters, the identification of the most optimal voltage vectors for producing the fastest torque dynamic responses will be carried out based on the investigation. The main benefit of the proposed strategy is that it provides superior fast torque dynamic response which is the main requirements for many AC drive applications, e.g. traction drives, electric transportations and vehicles.</span>


2013 ◽  
Vol 676 ◽  
pp. 209-212
Author(s):  
Lu Huan Shi ◽  
Yao Hui Li

In the electricity draws control system, the change of Low-velocity area of Rs will bring about a series of problem, especially the stator current and flux, will cause the distortion of the speed pulse vibration. The test discussed control scheme and optimization designs of asynchronous draw motors from exchange transmission electric locomotive operation characteristic demand. It adopts control strategy of neural network direct torque control (DTC) to control electricity draw the locomotive, to analyze the reacting of starting and sudden change of load, verifying this method may effectively improve the dynamic performance of the asynchronous motor, got up the very good inhibitory action to the low speed area torque pulsation. Thus the simulation results have proven the neural network DTC control strategy feasibility.


Author(s):  
Huzainirah Ismail ◽  
Fazlli Patkar ◽  
Auzani Jidin ◽  
Aiman Zakwan Jidin ◽  
Noor Azida Noor Azlan ◽  
...  

<p>Direct Torque Control (DTC) is widely applied for ac motor drives as it offers high performance torque control with a simple control strategy. However, conventional DTC poses some disadvantages especially in term of variable switching frequency and large torque ripple due to the utilization of torque hysteresis controller. Other than that, performance of conventional DTC fed by two-level inverter is also restricted by the limited numbers of voltage vectors which lead to inappropriate selection of voltage vectors for different speed operations. This research aims to propose a Constant Switching Frequency (CSF) torque controller for DTC of induction motor (IM) fed by three-level Neutral-Point Clamped (NPC) inverter. The proposed torque controller utilizes PI controller which apply different gain for different speed operation. Besides, the utilization of NPC inverter provides greater number of voltage vectors which allow appropriate selection of voltage vectors for different operating condition. Using the proposed method, the improvement of DTC drives in term of producing a constant switching operation and minimizing torque ripple are achieved and validated via experimental results.</p>


2013 ◽  
Vol 2013 ◽  
pp. 1-8 ◽  
Author(s):  
Dafang Wang ◽  
Zhenfei Hu ◽  
Cheng Zhu ◽  
Chuanwei Zhou ◽  
Yajing Xie

Voltage model is commonly used in direct torque control (DTC) for flux observing of asynchronous motor. In order to improve low-speed and dynamic performance of the voltage model, a modified low-pass filter (LPF) algorithm is proposed. Firstly, the tracking differentiator is brought in to modulate the measured stator current, which suppresses the measurement noise, and then amplitude and phase compensation is made towards the stator electromotive force (EMF), after which the stator flux is obtained through a low-pass filter. This method can eliminate the dynamic error of flux filtered by LPF and improve low-speed performance. Experimental results demonstrate effectiveness and improved dynamic performance of such method.


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