Development of an FPGA-based gate signal generator for a multilevel inverter

The application of Field Programmable Gate Array (FPGA) in the development of power electronics circuits control scheme has drawn much attention lately due to its shorter design cycle, lower cost and higher density. This paper presents an FPGA-based gate signal generator for a multilevel inverter employing an online optimal PWM switching strategy to control its output voltage. FPGA is chosen for the hardware implementation of the switching strategy mainly due to its high computation speed that can ensure the accuracy of the instants that gating signals are generated. The gate signal generator has been realized by an FPGA (FLEXlOKZO) from Altera. The design and development of the FPGA based gate signal generator is described in detail. Results from the timing simulation using MAX+PLUSII software are given and verified by the results obtained from the FLEXlOK2O output

Quality issues facing Malaysian higher learning institutions: a case study of Universiti Teknologi Malaysia

This chapter analyses the extent to which Malaysian universities have responded to the pressing call for enhancing institutional quality and advocating academic excellence. Malaysian universities have been challenged by both internal and external assessments that suggest that they are not on a par with their international competitors. As a result there have been great demands for an urgent remedy. This chapter explores the progress that has been made in responding to those demands and the limitations that have been encountered. In so doing it provides a case study that focuses on engineering programmes in particular. The chapter is intended to answer the question: can institutional quality improvement deliver the human capital that Malaysia needs in order to remain globally competitive

Analysis of AC-DC Converter Circuit Performance With Difference Piezoelectric Transducer Array Connection

This research presents a simulation analysis for the AC-DC converter circuit with a different configurations of the array connection of the piezoelectric sensor. The selection of AC-DC converter circuits is full wave bridge rectifier (FWBR), parallel SSHI (P-SSHI) and parallel voltage multiplier (PVM) with array configuration variation in series (S), parallel (P), series-parallel (SP) and parallel-series (PS). The system optimizes with different load configurations ranging from 10 kΩ to 1 MΩ. The best configuration of AC-DC converter with an appropriate array piezoelectric connection producing the optimum output of harvested power is presented. According to the simulation results, the harvested power produced by using P-SSHI converter connected with 3 parallel piezoelectric transducer array was 85.9% higher than for PVM and 15.88% higher than FWBR

Dynamic behaviour of EDM system through mathematical model

Electrical discharge machining (EDM) is a stochastic machining process which widely used to generate dies and molds. However, information about the EDM process is still at the earlier stage which lead to experience many challenges for further developments. Experimental analysis is time consuming as well as a costly procedure, due to the highly stochastic and complex nature of the process. Therefore, process modeling is an alternative to reduce the experimental costs related to the technology. This research proposes method to design a mathematical model of electrical discharge machining (EDM) system. The model will be used to understand the effects of machining parameters into the dynamic behaviour of EDM system based on the sparking phases and pulse power generator

Discharge analysis of EDM pulse generator

Electrical discharge machining (EDM) is a non-conventional manufacturing process used broadly in medical applications, aerospace industry and manufacturing in hard material fields. However, information about the process is still in an unfledged stage and it has been becoming a serious obstacle to its more improvements. In this paper, spark discharge condition is studied based on the simulated model of EDM spark pulse generator system equivalent form. Simulated model is verified by comparing with a series of experimental results. Frequency response is established through simplified model of EDM system. Influence of discharge time and stable discharge current on material removal rate (MRR) and stability of the system is analysed. This study is important to select the process parameters, and uses as a guidance to design the EDM spark pulse generator system

Classification of Machine Fault using Principle Component Analysis, General Regression Neural Network and Probabilistic Neural Network

As a major industry prime mover, induction motor plays an important role in manufacturing. In fact, production can cease its operation if there is some error or fault in the induction motor. In the industry, bearing, stator and rotor fault are the highest among other faults. Thus, this paper is to compare the accuracy of bearing, stator and rotor fault classification between General Regression Neural Network (GRNN) and Probabilistic Neural Network (PNN) with the previous work using Principle Component Analysis (PCA). The accuracy of fault classification for each method is improved by the selection of features extraction and number of classification. The features extraction used are mean, root mean square, skewness, kurtosis and crest factor. The sample data has been taken from Machinery Fault Simulator using accelerometer sensor, logged to text file using Labview software and analysed by using Matlab software. The accuracy of fault classification using GRNN method is higher than PNN because the sample data is classified through the regression of data as long as the sample data is redundant and lies on the regression distribution

An introductory CFD analysis study of novel cavity vane driven wind turbine blade design

Climate in Malaysia is heavily influenced by monsoon seasons, where the wind speed pattern is inconsistent and highly unsteady. Existing commercial wind turbines are only designed to accommodate high wind speed regions. In order to harvest energy in Malaysia, design modification is required on conventional wind turbine blade. This paper presents an introductory computational investigation of proposed drag driven vertical axis wind turbine. The objective of this research is to investigate the factors that govern the aerodynamics attributes of the proposed design. The design is simulated in 2D using sliding mesh technique via FLUENT based on URANS model. Previous mesh dependency study shows that fine and medium grid topology indicated a good agreement. In this numerical study, the proposed wind turbine is simulated based on SST k-ω turbulent transport model under fine grid spatial discretization. The design is analyzed under the influence of constant freestream velocity of 25 m/s in order to study the behavior of the turbine at high speed and low RPM. Result shows that high static pressure of 64.8 kPa exerts on the returning blade 1 which overwhelms the motion of advancing blade. Blade 1-3 indicated stable numerical values after 216°. Hence, the governing factors in terms of flow properties that affected the wind turbine are studied for future improvement. It is found that the cavity vane of the proposed design requires modification in order to improve moment

Integrated control of electrical discharge machining (EDM) using PSoC

Electrical discharge machining (EDM) is one of the earliest non-conventional machining in order to manufacture very accurate 3-D complex components on any electrically conductive materials. In die-sinking EDM, a pulse discharge occurs in a small spark gap between electrically conductive workpiece and electrode in dielectric medium. This paper proposed a new integrated control system using Programmable System-on-Chip (PSoC) for Die-sinking EDM in order to enhance Material Removal Rate (MRR). The MRR result of EDM-PSoC system is higher than EDM-Ben Fleming system due to the effect off high speed processing data analysis using PID algorithm in PSoC microcontroller and leads to improving system efficiency 41%

Surface modification of biomaterial embedded with pits using die sinker machine

Surface modification has been applied in many ways to enhance exclusive implant product. Electrical Discharge Machine Die Sinker (EDM DS) is a new approach to machine a macro surface on the biomaterial. In this study, investigations of current properties of EDM DS to obtain a new surface in titanium alloy (Ti-6Al-4V) and stainless steel (E-316-L), which placed pit on the material-sized (25 mm) diameter sample with a radius of 6.3 mm, were conducted. All the samples of concave textured circular pits with a fixed diameter and depth of 0.5 mm were successfully machined. This study revealed that the pits were produced in the concave cup and the lubricant was confined inside the pits, making easier contact between metal ball and metal concave surface. The results also show that the discharge machine is an attractive machining method for surface modification of biomaterial. This paper suggests that concave implant surface embedded with pits will work as a trap for lubricant and wear debris; in addition, it is possible to increase the lifespan of implant structure

Characterization of Enzyme Produced from Pseudomonas Putida for BTX (Benzene, Toluene & Xylene) Treatment in Petrochemical Industry Wastewater System

One of the big challenges in petrochemical industries is waste management. Currently, huge money was spending on the disposal of the waste. Industries are trying hard to find an alternative method to reduce the cost and improve the effectiveness of current waste management including treatment efficiency. Most of petrochemical wastes are containing benzene, toluene and xylene (BTX) which are very harmful to environment and living organisms. Common method used to separate the BTX from the waste are by using liquid-liquid and stripping process. One of the alternative to treat BTX is biological treatment method that used the natural capability of microorganisms to degrade to less harmful product is been applied. Some of examples are Pseudomonas Putida. (P. putida), Rhizobium, and Agrobacterium. P. putida is selected in this study for the biological treatment of BTX in petrochemical wastewater because it can produce an enzyme that has the capability of breakdown the aromatic hydrocarbon to carbon dioxide (CO2) and water (H2O). The main objective of this study is to produce and extract the enzymes produce, characterised the enzymes. This study also to investigate the effect of different concentration on the treatment as well as the growth of the bacteria. The enzyme is purified using salt precipitation and analysed using SDS_PAGE technique. UV-Vis is used to study the growth of the bacteria in the culture stock by measuring its optical density. The concentration of BTX was varied to determine the effect of the concentration on the percentage removal and the growth of P. putida. Enzymes detected or purified in this study was benzene reductase. Other expected enzymes were not able to be purified or analysed. It was found that in this experimental study, the removal of benzene is at 74% to 80%. The removal of toluene is at 62% to 75%. The removal of xylene is at 23% to 42%. Increasing the concentration of contaminants will reduce the removal capabilities