Articles
<![CDATA[Implementation of Space Vector Modulator for Cascaded H-Bridge Multilevel Inverters ]]>
<![CDATA[Syamim Sanusi]]>;
<![CDATA[Auzani Jidin]]>;
<![CDATA[Tole Sutikno]]>;
<![CDATA[Kasrul Abdul Karim]]>;
<![CDATA[Mohd Luqman Jamil]]>;
<![CDATA[Siti Azura Ahmad Tarusan]]>
<![CDATA[ International Journal of Power Electronics and Drive Systems (IJPEDS) Vol 6, No 4: December 2015 ]]>
Publisher : <![CDATA[Institute of Advanced Engineering and Science ]]>
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DOI: 10.11591/ijpeds.v6.i4.pp906-918
<![CDATA[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.]]>
<![CDATA[Bearingless Permanent Magnet Synchronous Motor using Independent Control ]]>
<![CDATA[Normaisharah Mamat]]>;
<![CDATA[Kasrul Abdul Karim]]>;
<![CDATA[Zulkiflie Ibrahim]]>;
<![CDATA[Tole Sutikno]]>;
<![CDATA[Siti Azura Ahmad Tarusan]]>;
<![CDATA[Auzani Jidin]]>
<![CDATA[ International Journal of Power Electronics and Drive Systems (IJPEDS) Vol 6, No 2: June 2015 ]]>
Publisher : <![CDATA[Institute of Advanced Engineering and Science ]]>
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DOI: 10.11591/ijpeds.v6.i2.pp233-241
<![CDATA[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.]]>
<![CDATA[Electromagnetic Performance due to Tooth-tip Design in Fractional-slot PM Brushless Machines ]]>
<![CDATA[Mohd Luqman Mohd Jamil]]>;
<![CDATA[Zulfikri Zaki Zolkapli]]>;
<![CDATA[Auzani Jidin]]>;
<![CDATA[Raja Nor Firdaus Raja Othman]]>;
<![CDATA[Tole Sutikno]]>
<![CDATA[ International Journal of Power Electronics and Drive Systems (IJPEDS) Vol 6, No 4: December 2015 ]]>
Publisher : <![CDATA[Institute of Advanced Engineering and Science ]]>
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DOI: 10.11591/ijpeds.v6.i4.pp860-868
<![CDATA[Permanent Magnet (PM) machines are favorable as an alternative to other machine topologies due to simpler construction and high torque density. However, it may result hight torque ripple due to an influence of cogging torque and electronic commutation. In this paper, comparisons of phase back-emf, static torque and cogging torque due to influence of tooth-tip asymmetry in 12-slot/10-pole double-layer and 12-slot/10-pole single layer winding machines are carried out using 2D Finite-Element Analysis. At rated condition, the stator asymmetry has great influence on the torque performance as there is significant reduction of torque ripple in 12-slot/10-pole mahine equipped with single layer winding than one equipped with double layer winding machine. It si confirmed that an optimum torque performance is desirable via stator iron modification in PM machines.]]>
<![CDATA[A review of direct torque control development in various multilevel inverter applications ]]>
<![CDATA[Siti Azura Ahmad Tarusan]]>;
<![CDATA[Auzani Jidin]]>;
<![CDATA[Mohd Luqman Mohd Jamil]]>;
<![CDATA[Kasrul Abdul Karim]]>;
<![CDATA[Tole Sutikno]]>
<![CDATA[ International Journal of Power Electronics and Drive Systems (IJPEDS) Vol 11, No 3: September 2020 ]]>
Publisher : <![CDATA[Institute of Advanced Engineering and Science ]]>
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DOI: 10.11591/ijpeds.v11.i3.pp1675-1688
<![CDATA[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.]]>
<![CDATA[A simple constant switching frequency of direct torque control of brushless DC motor ]]>
<![CDATA[Yusnida Ahmad Tarmizi]]>;
<![CDATA[Auzani Jidin]]>;
<![CDATA[Kasrul Abdul Karim]]>;
<![CDATA[T. Sutikno]]>
<![CDATA[ International Journal of Power Electronics and Drive Systems (IJPEDS) Vol 10, No 1: March 2019 ]]>
Publisher : <![CDATA[Institute of Advanced Engineering and Science ]]>
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DOI: 10.11591/ijpeds.v10.i1.pp10-18
<![CDATA[This paper discusses about direct torque control of Brushless DC motor by injecting the triangular waveform and using PI controller in order to reduce the torque and obtain constant switching frequency. Brushless DC motor are widely used in applications which require wide range of speed and torque control because of robust, longer lifespan, faster torque response and able to operate at high speed. Unlike conventional three phase DTC of induction machine (IM),the proposed DTC approach introduces two phase conduction mode. Besides that, the magnitude flux is considered constant in which the results only gains from constant torque region. Thus, the flux control loop is eliminated while implement this scheme. Using the triangular waveform that will be compare with actual torque, the proper switching pattern can be selected to control the generated torque and reducing commutation torque ripple. The torque response depends on the speed of the stator flux linkage which is directly controlled by selecting appropriate voltage space vectors from a look-up table to make sure the torque error within the band. The validity of the proposed control scheme for constant switching frequency and reduce torque ripple are verified through simulation and experimental results.]]>
<![CDATA[Constant Switching Frequency and Torque Ripple Minimization of DTC of Induction Motor Drives with Three-level NPC Inverter ]]>
<![CDATA[Huzainirah Ismail]]>;
<![CDATA[Fazlli Patkar]]>;
<![CDATA[Auzani Jidin]]>;
<![CDATA[Aiman Zakwan Jidin]]>;
<![CDATA[Noor Azida Noor Azlan]]>;
<![CDATA[Tole Sutikno]]>
<![CDATA[ International Journal of Power Electronics and Drive Systems (IJPEDS) Vol 8, No 3: September 2017 ]]>
Publisher : <![CDATA[Institute of Advanced Engineering and Science ]]>
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DOI: 10.11591/ijpeds.v8.i3.pp1035-1049
<![CDATA[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.]]>
<![CDATA[Improvement of Torque Capability of Direct Torque Control of Induction Machines ]]>
<![CDATA[Auzani Jidin]]>;
<![CDATA[New Lai Sim]]>;
<![CDATA[Tole Sutikno]]>
<![CDATA[ International Journal of Power Electronics and Drive Systems (IJPEDS) Vol 8, No 3: September 2017 ]]>
Publisher : <![CDATA[Institute of Advanced Engineering and Science ]]>
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DOI: 10.11591/ijpeds.v8.i3.pp1070-1079
<![CDATA[A control strategy for overmodulation operation of direct torque control hysteresis based in induction machine is proposed. The strategy is to extend the constant torque region as well as to improve the torque capability. The proposed overmodulation strategy is different to SVM based system where the reference stator voltage is available. In order for DTC hysteresis based system to be able to achieve that, several modifications have been applied so that the proposed overmodulation can be achieved by gradually transforming the PWM voltage waveform to six-step mode. Simulated results were provided to demonstrate the effectiveness of the strategy.]]>
<![CDATA[Multiphase Transformer Modelling using Finite Element Method ]]>
<![CDATA[Nor Azizah Mohd Yusoff]]>;
<![CDATA[Kasrul Abdul Karim]]>;
<![CDATA[Sharin Ab Ghani]]>;
<![CDATA[Tole Sutikno]]>;
<![CDATA[Auzani Jidin]]>
<![CDATA[ International Journal of Power Electronics and Drive Systems (IJPEDS) Vol 6, No 1: March 2015 ]]>
Publisher : <![CDATA[Institute of Advanced Engineering and Science ]]>
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DOI: 10.11591/ijpeds.v6.i1.pp56-64
<![CDATA[In the year of 1970 saw the starting invention of the five-phase motor as the milestone in advanced electric motor. Through the years, there are many researchers, which passionately worked towards developing for multiphase drive system. They developed a static transformation system to obtain a multiphase supply from the available three-phase supply. This idea gives an influence for further development in electric machines as an example; an efficient solution for bulk power transfer. This paper highlighted the detail descriptions that lead to five-phase supply with fixed voltage and frequency by using Finite-Element Method (FEM). Identifying of specification on a real transformer had been done before applied into software modeling. Therefore, Finite-Element Method provides clearly understandable in terms of visualize the geometry modeling, connection scheme and output waveform.]]>
<![CDATA[A Novel Optimal PI Parameter Tuning Strategy to Improve Constant Switching Performance of Direct Torque Control ]]>
<![CDATA[Sundram Ramahlingam]]>;
<![CDATA[Auzani Jidin]]>;
<![CDATA[Tole Sutikno]]>
<![CDATA[ International Journal of Power Electronics and Drive Systems (IJPEDS) Vol 7, No 2: June 2016 ]]>
Publisher : <![CDATA[Institute of Advanced Engineering and Science ]]>
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DOI: 10.11591/ijpeds.v7.i2.pp422-430
<![CDATA[This paper presents a novel method of optimal Propotional-Intergral (PI) controller’s parameter tuning strategy in-order to improve the Constant Switching Performance of 3-phase DTC shceme. The Direct Torque Control (DTC) sheme is acknowledged to provide fast decoupled control over the torque output and stator flux via a simple control structure. However, DTC sheme has two major downsides, which are the inconsistent inverter switching frequency and high torque output ripple. The main reason that contributes to these tribulations is the usage of hysteresis comparators in order to control the output torque. The realization of PI based controller method as replacement of hyterisis controller in DTC system able to provide significant solutions to over come the fall back while retaining the simple control structure of conventional DTC. The combination usage of higher sampling controller DS1004 and also 3-level CHMI in this system can further minimize the output torque ripple by providing higher resolution with lower digital error and greater number of vectors. This paper presents detail explanation and calculation of optimal PI parameter tuning strategy consecutively to enhance the performance of 3-level DTC system. In order to verify the feasibility of the proposed method experimentation, the proposed method is compared with convention DTC system via simulation and experiment results.]]>
<![CDATA[Stator flux in direct torque control using a speed and torque variation-based sector rotation approach ]]>
<![CDATA[Siti Azura Ahmad Tarusan]]>;
<![CDATA[Auzani Jidin]]>;
<![CDATA[Mohd Luqman Mohd Jamil]]>;
<![CDATA[Kasrul Abdul Karim]]>
<![CDATA[ International Journal of Power Electronics and Drive Systems (IJPEDS) Vol 12, No 3: September 2021 ]]>
Publisher : <![CDATA[Institute of Advanced Engineering and Science ]]>
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DOI: 10.11591/ijpeds.v12.i3.pp1326-1334
<![CDATA[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.]]>
