Improved control strategy of DFIG-based wind turbines using direct torque and direct power control techniques

This paper presents different control strategies for a variable-speed wind energy conversion system (WECS), based on a doubly fed induction generator. Direct Torque Control (DTC) with Space-Vector Modulation is used on the rotor side converter. This control method is known to reduce the fluctuations of the torque and flux at low speeds in contrast to the classical DTC, where the frequency of switching is uncontrollable. The reference for torque is obtained from the maximum power point tracking technique of the wind turbine. For the grid-side converter, a fuzzy direct power control is proposed for the control of the instantaneous active and reactive power. Simulation results of the WECS are presented to compare the performance of the proposed and classical control approaches.Peer reviewedFinal Accepted Versio

Fuzzy-based estimation of reference flux, reference torque and sector rotation for performance improvement of DTC-IM drive

In this study, the fuzzy-based reference flux estimator (RFE), reference torque estimator (RTE) and sector rotation strategy called fuzzy logic estimator are proposed to direct torque control of induction motor (DTC-IM) drive for performance improvement. The basic DTC-IM drive with conventional RFE, RTE and sector division causes large torque ripple, variable switching frequency and uneven voltage vector contribution in stator flux. The torque and speed responses of the proposed system are investigated with load variations. The simulation results of the proposed DTC-IM drive are compared with the basic DTC-IM drive. The assessment of the proposed system shows improved performance. A hardware is developed using Xilinx Spartan-6XC6SLX45-Field Programmable Gate Array (FPGA) Kit for experimental verification of the results. Moreover, sinusoidal pulse width modulation and space vector pulse width modulation techniques are applied to reduce the torque ripples. The performance of the drive is investigated for various speed ranges. The comparison of the simulated and experimental results proves that the proposed fuzzy-based DTC-IM drive provides better performance than the basic DTC-IM drive

Serangga dan mitos suku kaum jakun, Kampung Peta, Mersing Johor

This study focuses on seeing insects from the mythical perspective of the Orang Asli tribe of Jakun, Kampung Peta, Mersing Johor. The existence of insects in the life of every ethnic in Malaysia has brought various elements of myths. Therefore, when combining myths and insects, it could be said that myth is a human way of understanding, expressing and linking insects to him/herself as well as a group/culture. The practice of using insects among ethnic groups in daily life is called etnoentomology. In this study, the insects studied are the butterfly (Lepidoptera), the odonates (Odonata) and the cicadas (Homoptera). This is because these insects are very popular in the community and have their own myths that are brought into the local culture of belief

High Performance Multicell Series Inverter-Fed Induction Motor Drive

This document is the Accepted Manuscript version of the following article: M. Khodja, D. Rahiel, M. B. Benabdallah, H. Merabet Boulouiha, A. Allali, A. Chaker, and M. Denai, ‘High-performance multicell series inverter-fed induction motor drive’, Electrical Engineering, Vol. 99 (3): 1121-1137, September 2017. The final publication is available at Springer via DOI: https://doi.org/10.1007/s00202-016-0472-4.The multilevel voltage-source inverter (VSI) topology of the series multicell converter developed in recent years has led to improved converter performance in terms of power density and efficiency. This converter reduces the voltage constraints between all cells, which results in a lower transmission losses, high switching frequencies and the improvement of the output voltage waveforms. This paper proposes an improved topology of the series multicell inverter which minimizes harmonics, reduces torque ripples and losses in a variable-speed induction motor drive. The flying capacitor multilevel inverter topology based on the classical and modified phase shift pulse width modulation (PSPWM, MPSPWM) techniques are applied in this paper to minimize harmonic distortion at the inverter output. Simulation results are presented for a 2-kW induction motor drive and the results obtained demonstrate reduced harmonics, improved transient responses and reference tracking performance of the voltage in the induction motor and consequently reduced torque ripplesPeer reviewe

Implementation and Analysis of Direct Torque Control for Permanent Magnet Synchronous Motor Using Gallium Nitride based Inverter

Permanent magnet synchronous machines (PMSMs) attract considerable attention in various industrial applications, such as electric and hybrid electric vehicles, due to their high efficiency and high-power density. In this thesis, the mathematical model of PMSM and two popular control strategies, field-oriented control (FOC) and direct torque control (DTC), are analyzed and compared. The results demonstrated that the DTC has better dynamic response in comparison to FOC. Moreover, DTC can eliminate the use of position sensor, which will save the cost of the PMSM drive system. Therefore, this thesis focuses on the design and implementation of high-performance DTC for PMSMs with a Gallium Nitride (GaN) based high switching frequency motor drive. First, the characteristics and operation principles of a PMSM are introduced. Then, the mathematical models of a PMSM under different coordinate systems are investigated. Consequently, a PMSM model is developed based on the dq rotating reference frame and implemented in the MATLAB/Simulink for validation. Two advanced PMSM control strategies, FOC and DTC, are investigated and compared in terms of control performance through comprehensive simulation studies and the results demonstrate that DTC has better dynamic performance. Conventional DTC contributes to higher torque ripple in the PMSM due to the limited switching frequency in a conventional semiconductor-based motor drive, which inevitably deteriorates the drive performance. Therefore, this thesis aims to reduce the torque ripple in the DTC based PMSM drive by using the new generation wide bandgap switching devices. More specifically, DTC is improved by using the optimized space vector pulse width modulation strategy and a higher switching frequency contributed by the GaN based motor drive. Finally, the proposed DTC-SVM based PMSM control strategy is implemented on the digital signal processor (DSP) and evaluated on the laboratory GaN based PMSM drive. Both the simulation and experimental results show that the proposed improvement in the DTC can further improve the PMSM drive performance

5-level torque-hysteresis controller for DTC based IM drive

In the recent trade demand, the AC machines and drives are extensively utilized. Normally, the AC drives exploit with high efficacy as well as high performance. Among other things, one of the best control strategies is Direct torque control (DTC). For this article, the induction motor drive is projected very simple amended DTC scheme in accordance with the hysteresis controller. By the reason of its modest assembly & effective execution, DTC is used for AC as well as DC drive as associated to other monitoring structures. The presence of high ripple content in output torque for DTC scheme is only an obstacle. This article approaches extenuation of the ripples in torque by varying the predictable 5-level torque hysteresis controller used in DTC. The expansion of distinctive switching approach has been generated for chosen voltage vector. On the basis of ripple content simulation outcomes fulfilled in MATLAB/SIMULINK for hysteresis torque controller to minimized the ripples

Comparative Analysis of Direct Torque Control and Fuzzy Logic Control of Three Phase Induction Motor

Induction motors are the starting point to design an electrical drive system which is widely used in many industrial applications. With the joint progress of the power electronics and numerical electronics it is possible today to deal with the axis control with variable speed in low power applications. The direct torque control scheme provides excellent properties of regulation without rotational speed feedback. In this paper, Induction motor has been simulated in stationary d-q reference frame and its free acceleration characteristics are drawn. To reduce the ripple in current and voltage waveform space vector PWM method and fuzzy logic control is also implemented.

SISTEM PENGENDALIAN KECEPATAN MOTOR TIGA FASA MENGGUNAKAN METODE DIRECT TORQUE CONTROL (DTC)

Abstrak Artikel ilmiah ini merupakan pengembangan dari pengendalian kecepatan motor tiga fasa dengan metode direct torque control (DTC) dengan mensimulasikan menggunakan simulink. Pada studi ini, membahas pengendalian kecepatan motor 3 fasa yang banyak digunakan dalam dunia industri karena mempunyai banyak keunggulan diantaranya mudah dalam pemeliharaan, performanya yang handal, kontruksi yang kokoh, mempunyai efisiensi tinggi, dan harganya murah. namun, motor tiga fasa memeliki kekurangan diantaranya karkateristik motor yang sulit di kendalikan dan juga arus awal yang tinggi sehingga di butuhkan inverter tiga fasa. Inverter tiga fasa berfungsi sebagai pengendali laju motor tiga fasa dengan mengubah nilai frekuensi dan tegangan. Cara kerja inverter mengubah nilai frekuensi menjadi lebih kecil dengan mengubah tegangan AC menjadi tegangan DC, kemudian di ubah menjadi tegangan AC lagi dengan frekuensi yang berbeda. Pengaturan tegangan dan frekuensi diberlakukan untuk laju putaran dan torsi motor yang dibutuhkan. Metode yang digunakan untuk pengendalian kecepatan motor tiga fasa pada artikel ilmiah ini dengan space vector pulse widht modulation (SVPWM) menggunakan DTC dengan perbandingan fluks. Skema model SVPWM menggunakan perbandingan control P dan PI dengan metode DTC. Hasil simulasi pengendalian motor tiga fasa menunjukkan metode DTC ini tidak sensitive terhadap perubahan pada tahanan stator sehingga perubahan pada beban mempengaruhi kecepatan motor. Metode DTC dapat mempersingkat kecepatan motor tiga fasa sampai stabil pada 0,22s hingga 0,5s dimana 0,5s diberi beban torsi 6Nm ,12Nm, 18Nm , dan 24Nm sehingga terjadi penurunan kecepatan pada detik 0, 5s secara bertahap sesuai dengan beban torsi yang diberikan. Kata Kunci: direct torque control (DTC), SVPWM, motor tiga fasa, inverter, simulink Abstract This scientific article is a development of three phase motor speed control by direct torque control (DTC) method by simulating using simulink. In this study, discussing the control of 3 phase motor speed which is widely used in the industrial world because it has many advantages including easy maintenance, reliable performance, sturdy construction, high efficiency, and low price. however, three-phase motors have shortcomings including motor characteristics that are difficult to control and also high initial currents so a three-phase inverter is needed. The three-phase inverter functions as a three-phase motor speed controller by changing the frequency and voltage values. How the inverter works to change the value of the frequency to be smaller by changing the AC voltage to DC voltage, then convert it to AC voltage again with a different frequency. Voltage and frequency settings are applied to the required rotation speed and torque of the motor. The method used for controlling three-phase motor speed in this scientific article with space vector pulse widht modulation (SVPWM) uses DTC with flux comparison. The SVPWM model scheme uses a comparison of control P and PI with the DTC method. The results of a three-phase motor control simulation show that the DTC method is not sensitive to changes in stator resistance so that changes in load affect motor speed. The DTC method can shorten the speed of the three-phase motor until it is stable at 0.22s to 0.5s, where 0.5s are given a torque load of 6Nm, 12Nm, 18Nm, and 24Nm so that the speed decreases at 0,5s in stages according to the torque load given. Keywords: direct torque control (DTC), SVPWM, three phase motor, inverter, simulin