Marizan Sulaiman

Performance comparison of SVPWM and Hysteresis Current Control for Dual motor drives

Dual motor drives fed by single inverter are purposely designed to reduced sizes and cost with respect to single motor drives fed by single inverter. This paper presents the speed responses behavior of Dual Permanent Magnet Synchronous Motor (PMSM) driven base on two different PWM control schemes, which are Space Vector Pulse Width Modulation (SVPWM) and Hysteresis Current Controller. These two techniques are compared for wide range of speed and for variation of load. MATLAB/Simulink has been chosen as the simulation tools. The comparison between SVPWM controller and Hysteresis Current Controller for Dual PMSM fed by single inverter is presented. Both techniques show satisfactory speed regulation for a wide range of speed either with load, no load or variation of load.

Application of ZigZag Transformers to Mitigate Triplen Harmonics in 3 Phase 4 Wire Electrical Distribution System

This paper studies an application of wye-zigzag transforms for reducing harmonics in the neutral conductors of a three phase 415/240 V distribution system. Triplen harmonic currents add up in the neutral conductor of the distribution system feeding the non linear loads such as personal computers and electronic office machines with switch mode power supplies. The zigzag transformer is installed between the distribution panel and the high harmonics producing loads. This research makes use of a star-zigzag grounded transformer.

Independent speed sensorless control of dual parallel PMSM based on Five-Leg Inverter

This paper introduces a sensorless technique to drive independently dual Permanent Magnet Synchronous Motors (PMSM) based on Five-Leg Inverter (FLI). The main purpose of the proposed method is to eliminate the usage of speed sensor and to reduce the number of inverter switches from twelve to ten switches in the case of dual three-phase PMSMs drives. Despite the needs of speed sensor as the speed feedback for the dual PMSMs drives, there are no research done using sensorless technique in order to control independently dual three-phase PMSMs. A FLI contents ten switches which two switches represent as on e leg. For the five legs available, one leg is commonly connected to both PMSMs. The drive is simulated by using MATLAB/Simulink. The simulation results of the performance for Dual PMSMs fed by a FLI at rated speed are successfully achieved and offer potential result for hardware implementation. The applied technique shows good speed regulation and proves that Dual PMSMs can independently control at different speed operation either in forward or reverse operating conditions as well as for load disturbance.

Analysis of voltage stability problems in power system

Voltage stability analysis is important in power system in order to maintain the power system equilibrium. This research focuses on the voltage stability analysis of the power system feeders at distribution and transmission systems. The voltage stability analysis is carried out on the basis of single feeder comprising of two-bus system using ABCD line parameters. The feeders voltage in distribution and transmission system has been monitored at lagging and leading load conditions for various power factors. Hence, the active power-voltage (PV) curve and reactive power-voltage (QV) are used as tools to monitor the voltage stability at feeders. The plotting methods for PV and QV curves have been improved by using MATLAB applications software. The voltage critical, voltage regulation, voltage gap and line current are monitored at each load power factor.

Implementation of Shape – Based Matching Vision System in Flexible Manufacturing System

This research is regarding the application of a vision algorithm to monitor the operations of a system in order to control the decision making concerning jobs and work pieces recognition that are to be made during system operation in real time. This paper stress on the vision algorithm used which mainly focus on the shape matching properties of the product. The main focus of this paper is on the development of an adaptive training phase of the vision system, which is the creation of a flex- ible Region of Interest capability that is able to adapt to various type of applications and purposes depending on the users’ requirements. Additionally, an independent stand-alone control scheme was used to enable this system to be used in various types of manufacturing configurations. The system was tested on a number of different images with various characteristics and properties to determine the reliability and accuracy of the system in respect to different conditions and combination of different training traits.

Speed performance of SVPWM direct torque control for five leg inverter served dual three-phase induction motor

Independent control of multi-machine with single-converter systems is the motivation of this research study. As in the previous literature review, there is no report regarding speed control applying space vector pulse width modulation direct torque control (SVPWM-DTC) method for dual three-phase induction motor (IM) fed by a five leg inverter (FLI). Therefore, in this paper, a new and simple control method based on SVPWM-DTC for dual three-phase induction motors with only one drive of five-leg voltage source inverter is investigated. The method effectively allows independent control of two three-phase IMs. Simulations of different speed commands and variation of load condition tests have been performed. Future work is to do comparative study between vector controls (VC) versus DTC methods to the FLI performance.

Performance studies of three-phase cascaded H-Bridge and Diode-Clamped multilevel inverters

This paper discusses a concept of two types multilevel inverters including of Cascaded H-Bridge and Diode-Clamped for harmonic reduction on high power applications. Normally, multilevel inverters can be used to reduce the harmonic problems in electrical distribution systems. These studies focused on the performance and analysis of a three phase multilevel inverters including Cascaded H-Bridge and Diode Clamp based on SPWM approaches. Based on the various simulations on nine levels of multilevel inverters, we found that the Total Harmonics Distortion for voltage (THDv) output for both multilevel inverters is decreased. It also produces lower contents based on the IEC standard.

Optimization of fuzzy logic based for vector control induction motor drives

Recently, fuzzy logic controllers have been recognized in induction motor drives systems for their robust performance. Therefore, this paper presents a fuzzy logic (FL) control system based on FL approach for a vector controlled induction motor drives for high performance application. The analysis, design and simulation of the FL controller for vector control induction motor are carried out based on scaling factor and membership functions theory. First, the drives system was simulated with Standard Constant Parameter FL, Design Case Constant Parameter Fuzzy Logic and PI controller. Then the best performances of these controllers were compared to proposed optimized fuzzy logic controller (OFL). The OFL is done by tuning of scaling factor for the change in speed error, Gce to produce a better transient behaviour, and altering the width and moving the peak value positions of membership functions to improve control performance. The results show that the proposed OFL gives better performances in tracking performances and also load disturbances. The test is done in different operating conditions for half rated speed and full rated speed, half and full load condition. The results demonstrates the robustness and the effectiveness of OFL controller for high performance of induction motor drive system.

A GUI based per-unit representation of power system with symmetrical components: an e-learning approach

Every textbook on power system analysis discusses the per-unit system, varying in depth with problems and solutions. However, it is still not an interactive method for teaching and learning the per-unit representation. Thus, it needs a new approach to make teaching and learning process more interactive and interesting for students. The graphical user interface (GUI) provides the user with interactive visual communication to analyze the power systems. This paper presents the GUI based per-unit representation of power systems with symmetrical components in the visual basic (VB) environment. The software allows the user to draw the single line diagram representing the power system with ratings of each component. This GUI based per-unit system is developed for the teaching and learning environment of the power system analysis. The user can make use of this interactive software to calculate the per-unit impedance with respect to the system common MVA base. The reactance diagram of the three sequence impedances, namely, the zero-, positive-, and negative- sequence impedances, can be drawn either manually or automatically. It is hoped that this GUI software will enhance the learning process and make it more interactive, interesting and user friendly.

Auto-tuning sliding mode control for induction motor drives

Sliding mode control offers great potential to deal with uncertainties such as parameter variation and external load disturbances in controlling induction motor drives. The main obstacle of conventional sliding mode control is the presence of chattering phenomenon. It is known that the large switching gain of sliding mode control is proportional to the chattering level, and normally a large switching gain is applied to handle the uncertainties. In this paper, this chattering phenomenon is significantly reduced by a newly developed algorithm. The control algorithm incorporates the adjustment of switching gain value and variation of the boundary layer to replace the discontinuous function in conventional sliding mode control. As a result, the boundary layer and the switching gain will change in the presence of uncertainties and load disturbances. The experimental results show the effectiveness of the proposed sliding mode control is superior in reducing the chattering phenomenon and handling the external load disturbances.