Nik Rumzi Nik Idris | Universiti Teknologi Malaysia - UTM (original) (raw)

Papers by Nik Rumzi Nik Idris

International Journal of Power Electronics and Drive Systems, Jun 1, 2017

This paper presents a study on a new full bridge series resonant converter (SRC) with wide zero v... more This paper presents a study on a new full bridge series resonant converter (SRC) with wide zero voltage switching (ZVS) range, and higher output voltage. The high frequency transformer is connected in series with the LC series resonant tank. The tank inductance is therefore increased; all switches having the ability to turn on at ZVS, with lower switching frequency than the LC tank resonant frequency. Moreover, the step-up high frequency (HF) transformer design steps are introduced in order to increase the output voltage to overcome the gain limitation of the conventional SRC. Compared to the conventional SRC, the proposed converter has higher energy conversion, able to increase the ZVS range by 36%, and provide much higher output power. Finally, the a laboratory prototypes of the both converters with the same resonant tank parameters and input voltage are examined based on 1 and 2.2 kW power resprctively, for veryfing the reliability of the performance and the operation principles of both converters.

TELKOMNIKA Telecommunication Computing Electronics and Control, Mar 1, 2016

The major problems in hysteresis-based DTC are high torque ripple and variable switching frequenc... more The major problems in hysteresis-based DTC are high torque ripple and variable switching frequency. In order to minimize the torque ripple, high sampling time and fast digital realization should be applied. The high sampling and fast digital realization time can be achieved by utilizing high-speed processor where the operation of the discrete hysteresis regulator is becoming similar to the operation of analog-based comparator. This can be achieved by utilizing field programmable gate array (FPGA) which can perform a sampling at a very high speed, compared to the fact that developing an ASIC chip is expensive and laborious.

Proceeding of the Electrical Engineering, Computer Science and Informatics (EECSI) Conference, Oct 1, 2017

This paper presents some of the main problems, as well as their root causes, of Direct Torque Con... more This paper presents some of the main problems, as well as their root causes, of Direct Torque Control (DTC) 3-phase induction motor drive. The high torque ripple in DTC drive due to the hysteresis controller inevitably becomes worst with the discrete implementation of the drive system. The hysteresis controller also causes variable switching frequency that depends on operating conditions, especially the speed. The simplification used in stator flux expression for voltage vectors selection in flux control results in a poor flux regulation at low speed. To overcome these problems, techniques that have been implemented at UTM-PROTON Future Drive Laboratory (UPFDL) are presented and described. Some experimental results obtained from the previous works are also presented and discussed.

This paper presents a simple overmodulation method employed in direct torque control (DTC) consta... more This paper presents a simple overmodulation method employed in direct torque control (DTC) constant switching frequency (CSF) controller of induction machines. The proposed overmodulation method is utilized to extend a constant torque region and hence produce high torque capability in field-weakening region with six-step operation. It will be shown that the overmodulation operation using the DTC-CSF scheme can be established by controlling the stator flux locus from circular to the hexagonal shape. This is achieved by modifying the flux error status produced from the flux hysteresis controller before it is fed to the lookup table. The main benefit of the proposed method is its simplicity since it requires only a minor modification to the conventional DTC hysteresis-based structure and does not require a space-vector modulator.

International Journal of Electrical and Computer Engineering, Apr 1, 2016

This paper proposes a novel flux observer based on Extended Kalman Filter (EKF) for high performa... more This paper proposes a novel flux observer based on Extended Kalman Filter (EKF) for high performance vector control of 3-phase Induction Motor (IM) drives under stator winding open-phase fault. The presented flux estimation combines the Indirect Rotor Field-Oriented Control (IRFOC) method. The rotor flux is obtained from two modified EKF with two different stator currents (forward and backward stator currents). The proposed technique can significantly reduce the DC-offset problem on the pure integrator associated with the basic IRFOC method. The Matlab simulation results confirm the validity of the proposed strategy.

Telkomnika: Indonesian Journal of Electrical Engineering, Dec 1, 2014

This study investigates the simple vector control of a 3-phase squirrel cage Induction Motor (IM)... more This study investigates the simple vector control of a 3-phase squirrel cage Induction Motor (IM) under open-circuit fault (faulty 3-phase IM). It was shown that it is needed to supply the stator windings with unbalanced currents to remove the oscillating term of the machine electromagnetic torque. The vector control system is based upon Field-Oriented Control (FOC) that has been adapted for this type of machine. Simulation results are provided to show the operation of the proposed drive system.

International Journal of Power Electronics and Drive Systems, Sep 1, 2015

This paper investigates the vector control of a star-connected three-phase Induction Motor (IM) u... more This paper investigates the vector control of a star-connected three-phase Induction Motor (IM) under stator winding open-phase fault. The used vector control method is based upon indirect rotor field-orientation concepts that have been adapted for this type of machine. Beside the implementation of this method in critical industrial applications, the proposed method in this paper can be used for vector control of unbalanced 2-phase or single-phase IM with two main and auxiliary windings. Simulation results are provided to show the operation of the proposed drive system.

International Journal of Electrical and Computer Engineering (IJECE)

Single-ended primary-inductor converter (SEPIC) was considered a good alternative to a DC-DC conv... more Single-ended primary-inductor converter (SEPIC) was considered a good alternative to a DC-DC converter for photovoltaic (PV) systems. The SEPIC converter can operate with an input voltage greater or less than the regulated output voltage, or as a step-up or step-down. As a step-up converter, SEPIC boosts PV voltage to specific levels. However, gain limitation and voltage stress continue to reduce the efficiency of conventional SEPIC converters. Because of this, researchers created a modified SEPIC converter to improve performance. In this paper, six modified SEPIC converters were compared and evaluated. To compare fairly, all modified SEPIC converters are non-isolated and use a single switch. Power simulator (PSIM) software was used to simulate each converter with a BISOL BMO-250 PV module and maximum power point tracking (MPPT) P&O controller. The converter with the highest static voltage gain and lowest duty cycle has been identified. It results in up to ten times voltage incremen...

International Journal of Power Electronics and Drive Systems (IJPEDS)

The conventional induction motor rotor flux observer based on current model and voltage model are... more The conventional induction motor rotor flux observer based on current model and voltage model are sensitive to parameter uncertainties. In this paper, a non-parametric induction motor rotor flux estimator based on feed-forward neural network is proposed. This estimator is operating without motor parameters and therefore it is independent from parameter uncertainties. The model is trained using Levenberg-Marquardt algorithm offline. All the data collection, training and testing process are fully performed in MATLAB/Simulink environment. A forced iteration of 1,000-epochs is imposed in the training process. There are overall 603,968 datasets are used in this modeling process. This four-input two-output neural network model is capable of providing rotor flux estimation for field-oriented control systems with 3.41e-9 mse and elapsed 28 minutes 49 seconds training time consumption. This proposed model is tested with reference speed step response and parameters uncertainties. The result i...

International Journal of Power Electronics and Drive Systems (IJPEDS), 2015

Torque calculation process is one of the major concerns for controlling induction motors in indus... more Torque calculation process is one of the major concerns for controlling induction motors in industry, which requires very accurate state estimation of unmeasurable variables of nonlinear models. This can be solved if the variables used for torque calculation is accurately estimated. This paper presents a torque calculation based on a voltage model represented with a low-pass filter (LPF), and an extended Kalman filter (EKF). The experimental results showed that the estimated torque at low speed based on EKF is more accurate in the expense of more complicated and larger computational time.

International Journal of Power Electronics and Drive Systems (IJPEDS), 2015

In this paper, two kinds of observers are proposed to investigate torque estimation. The first on... more In this paper, two kinds of observers are proposed to investigate torque estimation. The first one is based on a voltage model represented with a low-pass filter (LPF); which is normally used as a replacement for a pure integrator to avoid integration drift problem due to dc offset or measurement error. The second estimator used is an extended Kalman filter (EKF) as a current model, which puts into account all noise problems. Both estimation algorithms are investigated during the steady and transient states, tested under light load, and then compared with the measured mechanical torque. In all conditions, the torque estimation error for EKF has remained within a narrow error band and yielded minimum torque ripples, which motivate the use of the EKF estimation algorithm in high performance control drives of IMs for achieving high dynamic performance.

Renewable and Sustainable Energy Reviews, 2017

Single-Phase Induction Motor (SPIM) is the main contributor to the electricity consumption in res... more Single-Phase Induction Motor (SPIM) is the main contributor to the electricity consumption in residential and commercial sectors where three-phase power supply is not available. SPIM efficiencies range from as low as 30% to as high as 65%, depending on the motor type and design. To guarantee the efficient use of energy, the investigation of different SPIM drives have been increased in recent decades. Efficient control policies of SPIM drives offer a great potential for energy saving. Thus research on optimum operation of SPIM drives is escalating. However, there seems to be an absence of a comprehensive review on Variable Speed Control (VSC) techniques for SPIM drives in order to address the need for a thorough insight on SPIMs' drives. In this paper, the principal of control techniques for SPIM drives is explained and their pros and cons are discussed. Ultimately, from different perspectives, VSC techniques for SPIM drives are compared and appraised. It is envisaged that this paper will be a valuable one-stop source of information for researchers working in this topic.

Journal of Power Electronics, 2011

This paper describes a hybrid induction motor drive system incorporating DTC-hysteresis and Direc... more This paper describes a hybrid induction motor drive system incorporating DTC-hysteresis and Direct Self Control (DSC) schemes to achieve excellent dynamic performance. The control scheme is switched from a circular to a hexagonal flux locus whenever a dynamic condition is encountered. On the other hand, when the motor operates under steady state conditions, a circular flux locus is used. Without major modifications to the simple structure of a basic DTC, hexagonal flux locus operation is established by modifying the flux error status, before it is fed to the look-up table. The feasibility of the proposed hybrid scheme to achieve excellent control performance is verified by experimental results.

TELKOMNIKA Indonesian Journal of Electrical Engineering, 2015

Three-phase Induction Motor (IM) drives are widely used in industrial equipments. One of the esse... more Three-phase Induction Motor (IM) drives are widely used in industrial equipments. One of the essential problems of 3-phase IM drives is their high speed and torque pulsation in the fault conditions. This paper shows Direct Torque Control (DTC) strategy for vector control of a 3-phase IM under opencircuit fault. The objective is to implement a solution for vector control of 3-phase IM drives which can be also used under open-phase fault. MATLAB simulations were carried out and performance analysis is presented.

TELKOMNIKA (Telecommunication Computing Electronics and Control), 2015

The industrial requirements for the control of an induction motor (IM) under fault conditions con... more The industrial requirements for the control of an induction motor (IM) under fault conditions continue to be of attention, as evidenced by the majority current publications. The focus is on developments of control methods which can be used for faulty IM. A novel vector control technique based on stator field-oriented control (SFOC) for a 3-phase IM under open-phase fault is proposed in this paper. MATLAB simulation results are presented to illustrate the improvement in performance of the proposed algorithm. It has shown that for providing an appropriate algorithm to control faulty machine with one opened phase, the modification in the conventional controller is possible.

TELKOMNIKA (Telecommunication Computing Electronics and Control), 2011

Makalah ini menghadirkan strategi kendali berbagi-energi parallel untuk aplikasi kendaraan hibrid... more Makalah ini menghadirkan strategi kendali berbagi-energi parallel untuk aplikasi kendaraan hibrida fuel cell (FCHV). Catudaya hibrida terdiri dari pembangkit fuel cell (FC) dan unit penyimpang energy (ESU) yang mengkombinasikan modul baterai dan kapasitor ultra. Bus arus DC digunakan untuk antar muka antara catudaya dan sistem pendorong kendaraan elektrik (EV). Catudaya dan sistem pendorong ini dikoneksikan ke bus DC konversi elektronika daya. Terdapat enam kalang kendali didesain pada sistem supervisi untuk mengatur tegangan bus DC, mengendalikan aliran arus listrik dan pada waktu yang sama memonitor kondisi pengisian dari masing-masing piranti penyimpan energi. Pengendali proposional integral (PI) diterapkan untuk mengatur keluaran dari tiap-tiap kalang kendali mengacu kepada sinyal referensinya. Sistem kendali energy yang diusulkan disimulasikan pada lingkungan MATLAB/Simulink. Hasil penelitian mengindikasikan bahwa sistem kendali berbagi-energi paralel yang diusulkan mampu menyediakan tanggapan kendaraan hibrida yang praktis terhadap tanggapan traksi kendaraan elektrik dan pada waktu yang sama mampu menghindarkan FC dan baterai dari beban lebih.

2014 IEEE Symposium on Computer Applications and Industrial Electronics (ISCAIE), 2014

2014 IEEE Conference on Energy Conversion (CENCON), 2014

ABSTRACT This paper presented a d-q model of a three-phase induction motor with two stator phases... more ABSTRACT This paper presented a d-q model of a three-phase induction motor with two stator phases open-circuit (faulty threephase induction motor). It is shown that with an appropriate transformation, the d-q model of faulty motor has the same structure of equation as a balanced three-phase induction motor. Based on the developed model of the faulty induction motor, simulations are carried out to study on the dynamic behavior of the faulty three-phase induction motor. The developed model for faulty 3-phase induction motor can be extremely

International Journal of Power Electronics and Drive Systems (IJPEDS), 2014

Nowadays, Field-Oriented Control (FOC) strategies broadly used as a vector based controller for S... more Nowadays, Field-Oriented Control (FOC) strategies broadly used as a vector based controller for Single-Phase Induction Motors (SPIMs). This paper is focused on Direct Rotor FOC (DRFOC) of SPIM. In the proposed technique, transformation matrices are applied in order to control the motor by converting the unbalanced SPIM equations to the balanced equations (in this paper the SPIM with two different stator windings is considered). Besides this control technique, a method for speed estimation of SPIM based on Extended Kalman Filter (EKF) to achieve the higher performance of SPIM drive system is presented. Simulation results are provided to demonstrate the high performance of the presented techniques.

Turkish Journal of Electrical Engineering and Computer Sciences, 2010

The discontinuous space vector pulse-width modulation (DSVPWM) is a well-known technique offering... more The discontinuous space vector pulse-width modulation (DSVPWM) is a well-known technique offering lower switching losses than continuous SVPWM. At the same, average switching frequency, or a switching frequency 1.5 times higher than utilized in continuous SVPWM, the discontinuous SVPWM results in lower current harmonic distortions than that obtained in continuous SVPWM at high modulation indices. This paper is concerned with the design and realization of new FPGA approach based a 5-segment discontinuous SVPWM operated at 40 kHz switching frequency. It will be shown that the implementation of the discontinuous SVPWM utilized in FPGA, to execute some complex tasks, is simplified through this new straightforward approach. For example, the judging of sectors, the computation of on-duration or firing pulses to control the switching of power switching devices can be executed much simpler with the proposed arithmetic logics or digital calculation in FPGA. In this way, the sampling frequency and hence switching frequency be increased. The SVPWM scheme has been implemented successfully based on APEX20KE Altera FPGA considering hardware resource saving. The validity of the proposed scheme has been tested experimentally to drive a 1.5 kW induction machine with low current harmonic distortions.