Constant Switching Frequency and Torque Ripple Minimization of DTC of Induction Motor Drives with Three-level NPC Inverter

2017 ◽  
Vol 8 (3) ◽  
pp. 1035
Author(s):  
Huzainirah Ismail ◽  
Fazlli Patkar ◽  
Auzani Jidin ◽  
Aiman Zakwan Jidin ◽  
Noor Azida Noor Azlan ◽  
...  
Keyword(s):  
Induction Motor ◽  
High Performance ◽  
Direct Torque Control ◽  
Torque Ripple ◽  
Motor Drives ◽  
Torque Control ◽  
Switching Frequency ◽  
Ac Motor ◽  
Hysteresis Controller ◽  
Selection Of

<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>

Improved Torque Control Performance in Direct Torque Control using Optimal Switching Vectors

2015 ◽  
Vol 5 (3) ◽  
pp. 441 ◽  
Author(s):  
Muhd Zharif Rifqi Zuber Ahmadi ◽  
Auzani Jidin ◽  
Maaspaliza Azri ◽  
Khairi Rahim ◽  
Tole Sutikno
Keyword(s):  
Induction Motor ◽  
Direct Torque Control ◽  
Induction Machine ◽  
Torque Ripple ◽  
Torque Control ◽  
Multilevel Inverter ◽  
Switching Frequency ◽  
Optimal Switching ◽  
Steady State Condition ◽  
Selection Of

This paper presents the significant improvement of Direct Torque Control (DTC) of 3-phases induction machine using a Cascaded H-Bidge Multilevel Inverter (CHMI). The largest torque ripple and variable switching frequency are known as the major problem founded in DTC of induction motor. As a result, it can diminish the performance induction motor control. Therefore, the conventional 2-level inverter has been replaced with CHMI the in order to increase the performance of the motor either in dynamic or steady-state condition. By using the multilevel inverter, it can produce a more selection of the voltage vectors. Besides that, it can minimize the torque ripple output as well as increase the efficiency by reducing the switching frequency of the inverter. The simulation model of the proposed method has been developed and tested by using Matlab software. Its improvements were also verified via experimental results.

scholarly journals Minimization of Torque Ripple in DTC of Induction Motor Using Fuzzy Mode Duty Cycle Controller

2011 ◽  
Vol 7 (1) ◽  
pp. 42-49
Author(s):  
Turki Abdalla ◽  
Haroution Hairik ◽  
Adel Dakhil
Keyword(s):  
Induction Motor ◽  
Duty Cycle ◽  
Direct Torque Control ◽  
Torque Ripple ◽  
Operating Conditions ◽  
Torque Control ◽  
Voltage Source ◽  
Ratio Method ◽  
Duty Ratio ◽  
Switching Frequency

Among all control methods for induction motor drives, Direct Torque Control (DTC) seems to be particularly interesting being independent of machine rotor parameters and requiring no speed or position sensors. The DTC scheme is characterized by the absence of PI regulators, coordinate transformations, current regulators and PWM signals generators. In spite of its simplicity, DTC allows a good torque control in steady state and transient operating conditions to be obtained. However, the presence of hysterics controllers for flux and torque could determine torque and current ripple and variable switching frequency operation for the voltage source inverter. This paper is aimed to analyze DTC principles, and the problems related to its implementation, especially the torque ripple and the possible improvements to reduce this torque ripple by using a proposed fuzzy based duty cycle controller. The effectiveness of the duty ratio method was verified by simulation using Matlab/Simulink software package. The results are compared with that of the traditional DTC models.

scholarly journals Direct Torque Control for Induction Motor Drive with Reduced Torque and Flux Ripples

2020 ◽  
Vol 8 (6S) ◽  
pp. 101-106
Keyword(s):  
Induction Motor ◽  
Control Method ◽  
Asynchronous Motor ◽  
Direct Torque Control ◽  
Torque Control ◽  
Control Algorithms ◽  
Induction Motor Drive ◽  
Ac Motor ◽  
Three Phase ◽  
Hysteresis Controller

The most universally used electric motor is an induction motor fed with three phase supply and eighty percent of mechanical power utilized by industries is given by three phase asynchronous ac motor. Direct torque control method is one such technique for controlling flux and torque of an asynchronous motor fed with PWM VSI. Without any complex control algorithms, it provides easy commands for the control of induction motor flux as well as torque. We are demonstrating the principle of DTC of an asynchromous motor using three level hysteresis controller in this paper. Philosophy of DTC with aforementioned control method has been simulated using MATLAB/Simulink.

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