Siti Azura Ahmad Tarusan
Universiti Teknikal Malaysia Melaka

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Implementation of Space Vector Modulator for Cascaded H-Bridge Multilevel Inverters Syamim Sanusi; Auzani Jidin; Tole Sutikno; Kasrul Abdul Karim; Mohd Luqman Jamil; Siti Azura Ahmad Tarusan
International Journal of Power Electronics and Drive Systems (IJPEDS) Vol 6, No 4: December 2015
Publisher : Institute of Advanced Engineering and Science

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.11591/ijpeds.v6.i4.pp906-918

Abstract

The Space Vector Modulation (SVM) technique has gained wide acceptance for many AC drive applications, due to a higher DC bus voltage utilization (higher output voltage when compared with the SPWM), lower harmonic distortions and easy digital realization. In recent years, the SVM technique was extensively adopted in multilevel inverters since it offers greater numbers of switching vectors for obtaining further improvements of AC drive performances. However, the use of multilevel inverters associated with SVM increases the complexity of control algorithm (or computational burden), in obtaining proper switching sequences and vectors. The complexity of SVM computation causes a microcontroller or digital signal processor (DSP) to execute the computation at a larger sampling time. This consequently may produce errors in computation and hence degrades the control performances of AC motor drives. This paper presents a developement of SVM modulator for three-level Cascaded H-Bridge Multilevel Inverter (CHMI) using a hybrid controller approach, i.e. with combination between the DS1104 Controller Board and FPGA. In such way, the computational burden can be minimized as the SVM tasks are distributed into two parts, in which every part is executed by a single controller. This allows the generation of switching gates performed by FPGA at the minimum sampling time 〖DT〗_2=540 ns to obtain precise desired output voltages, as can be verified via simulation and experimental results.
Bearingless Permanent Magnet Synchronous Motor using Independent Control Normaisharah Mamat; Kasrul Abdul Karim; Zulkiflie Ibrahim; Tole Sutikno; Siti Azura Ahmad Tarusan; Auzani Jidin
International Journal of Power Electronics and Drive Systems (IJPEDS) Vol 6, No 2: June 2015
Publisher : Institute of Advanced Engineering and Science

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.11591/ijpeds.v6.i2.pp233-241

Abstract

Bearingless permanent magnet synchronous motor (BPMSM) combines the characteristic of the conventional permanent magent synchronous motor and magnetic bearing in one electric motor. BPMSM is a kind of high performance motor due to having both advantages of PMSM and magnetic bearing with simple structure, high efficiency, and reasonable cost. The research on BPMSM is to design and analyse BPMSM by using Maxwell 2-Dimensional of ANSYS Finite Element Method (FEM). Independent suspension force model and bearingless PMSM model are developed by using the method of suspension force. Then, the mathematical model of electromagnetic torque and radial suspension force has been developed by using Matlab/Simulink. The relation between force, current, distance and other parameter are determined. This research covered the principle of suspension force, the mathematical model, FEM analysis and digital control system of bearingless PMSM. This kind of motor is widely used in high speed application such as compressors, pumps and turbines.
A review of direct torque control development in various multilevel inverter applications Siti Azura Ahmad Tarusan; Auzani Jidin; Mohd Luqman Mohd Jamil‬; Kasrul Abdul Karim; Tole Sutikno
International Journal of Power Electronics and Drive Systems (IJPEDS) Vol 11, No 3: September 2020
Publisher : Institute of Advanced Engineering and Science

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.11591/ijpeds.v11.i3.pp1675-1688

Abstract

Multilevel inverter (MLI) is commonly utilized in direct torque control (DTC) for medium and high power applications. The additional voltage vectors generated by MLI can be manipulated to achieve the optimal selection for the inverter switching states in the DTC control systems. Previously, a review of DTC which focused more on the two-level inverter for induction motor as well as a review of the multilevel converter in industrial applications had been implemented individually. However, a review on DTC development in MLI was insufficient in both papers. Therefore, this paper aims to give a comprehensive review of the improvement of DTC via various MLI applications. It is reviewed according to the applicable multilevel inverter topologies in the DTC system. The comparison of DTC by using conventional and multilevel inverter is synthesized. Thus, this review paper will hopefully lead researchers in further research activities actively.
Stator flux in direct torque control using a speed and torque variation-based sector rotation approach Siti Azura Ahmad Tarusan; Auzani Jidin; Mohd Luqman Mohd Jamil; Kasrul Abdul Karim
International Journal of Power Electronics and Drive Systems (IJPEDS) Vol 12, No 3: September 2021
Publisher : Institute of Advanced Engineering and Science

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.11591/ijpeds.v12.i3.pp1326-1334

Abstract

A typical problem of traditional DTCs is that the stator flux fails to regulate at low running speeds. The regulation of stator flux in DTC is disrupted because of the unavoidable voltage drop across the stator resistance. As a result, one of the solutions to the problem is to use a fixed sector rotation technique. The concept is based on decreasing stator flux droop, a simple technique for changing the flux locus sector at a certain angle. This method, however, is only effective at low working speeds at one value of torque. As a result, the stator flux droop effect at various speeds as well as torque must be studied. The study is carried out in this paper using simulation (MATLAB/Simulink) and a practical setup (dSPACE board) where both have performed similar outcomes. The comparison is done between the conventional method (without a strategy) and the proposed method (with strategy). In summary, the effect of stator flux droop has been found to have an inverse linear relationship to the speed and torque variation.
Torque ripple minimization in direct torque control at low-speed operation using alternate switching technique Muhammad Zaid Aihsan; Auzani Jidin; Azrita Alias; Siti Azura Ahmad Tarusan; Zuraidi Md Tahir; Tole Sutikno
International Journal of Power Electronics and Drive Systems (IJPEDS) Vol 13, No 1: March 2022
Publisher : Institute of Advanced Engineering and Science

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.11591/ijpeds.v13.i1.pp631-642

Abstract

Direct torque control (DTC) of induction motor is prominent to offer instant torque and flux control with a simple control structure. However, this scheme suffers from two major drawbacks namely high torque ripple and variable switching frequency of the inverter, especially during low-speed operation. During the low-speed condition, the positive torque slope is very steep and torque overshoot occurs frequently resulting in the torque ripple become of great significance. This paper proposes a new and effective technique to reduce the torque ripple by integrating the alternate switching technique to the inverter switching status to limit the torque slope surge. By varying the frequency and duty cycle of the alternate switching, the rate of surge can be controlled resulting in the chances of overshoots, and selection of reverse voltage vector can be avoided. The feasibility of the proposed technique has been validated using MATLAB/Simulink software and through experimental results. The results show the proposed alternate switching technique minimizes over 40% reduction in the torque ripple while maintaining the simple structure of DTC.
The simulation analysis of stator flux droop minimization in direct torque control open-end winding induction machine Muhammad Zaid Aihsan; Auzani Jidin; Siti Azura Ahmad Tarusan; Tole Sutikno
International Journal of Electrical and Computer Engineering (IJECE) Vol 13, No 3: June 2023
Publisher : Institute of Advanced Engineering and Science

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.11591/ijece.v13i3.pp3561-3571

Abstract

Direct torque control (DTC) using dual-inverter technique is one of the best topologies for electric vehicle (EV) as it offers abundant selection of voltage vectors to drive the induction machine (IM). This dual-inverter technique also more reassuring as the system still workable even any of its voltage supply is disrupted or the power pack is drained. However, during the uneven voltage supply, the movement of voltage vectors is interrupted and will move obliquely especially in medium voltage vectors. This situation will lead to the faulty movement of the voltage vectors in the default sector definitions and lead to huge flux droop, which later could impose to distort phase current. This paper proposes an optimal sector definition based on the preset voltage ratio between the two inverters. The voltage vectors can be mapped tangentially to the flux vector, minimizing the flux droop and improving the phase current waveform when the proposed sector is utilized. The effectiveness of the proposed sector is tested using MATLAB/Simulink software and the exact parameter from the induction machine.