This book contents an elaborate analysis on the SPWM (Sine Pulse Width Modulation) Boost Inverter especially for the grid connected PV power system. Reactive power control strategy of Boost Inverter at the inverter side has also been studied. By changing the modulation index of the Boost Inverter the output parameters have been varied. A range of modulation index has also been prescribed within which the percentage of THD (Total Harmonic Distortion)is in a tolerable range according to the IEEE standard 519. Moreover, a rigorous analysis on a set of different parameters along with the simulation results has been made and compared to investigate the proper characteristics of this device.
Most of researchers studied a Shunt Active Power Filters (SAPF) based on conventional two-level inverters with conventional controllers that requires a complex and a complicated mathematical model. In order to overcome this problem a Hysteresis band controller based diode clamped multilevel inverter is implemented and extended to a five level shunt active power filter. This research investigates the design of Hysteresis band controller biasing multilevel inverter to works as Shunt Active Power Filter (SAPF). Making use of the multilevel inverter advantages of less total harmonic distortion and reduced semiconductor ratings compare with conventional inverter. A three phase 5- level diode clamped Multi-Level Inverter (5-LDCMLI) uses as a voltage source inverter (VSI). The Hysteresis band controller determines the optimum switching pattern needed for the inverter to compensate the current harmonics and the reactive power of the load. The inverter is investigated by this study using MATLAB Simulink.
The design and analysis of an experimental study on single-phase Pulse Width Modulation inverter are presented in this work. The study also aims to enhance knowledge on experimental studies in the lab. In this work, Implementation and analysis of PWM switching pulses with digital technique for single phase full bridge inverter is presented. A switching strategy will be proposed to be used for full bridge single phase inverter. The main advantage of these strategies is that it does not requir additional circuit to generated inverter’s dead time. In this book, the PWM equations are studied and the switching pulses are calculated. This research investigates several control techniques applied to the Single Phase Inverter in order to ensure an efficient voltage utilization and better harmonic spectrum. A modeling and control strategy of a single phase Inverter is also investigated. Computer simulation results using Simulink/Matlab program are reported and discussed together with a comparative study of the different control techniques.The single phase full bridge inverter implemented using IGBT has been developed to test the switching pulses generated by micro-controller (AT89S52).
Solid state power frequency changers are used for various purposes.The usual practice to get variable frequency power source is to use rectifier-inverter combination.Unfortunately the conventional diode/thyristor bridge rectifiers at the input side cause several problems such as:low input power factor,considerable harmonic distortion of ac currents and harmonic pollution on grid. The PWM rectifier is a preferred choice for providing ac to d.c conversion,due to its capability of input p.f regulation,line harmonic current mitigation,d.c voltage control and bidirectional power flow.In this thesis work,the theory behind a three phase PWM rectifier has been studied.a controller is designed to regulate the output voltage and input power factor.The entire system with its controller is modeled and simulated in MATLAB-simulink to verify the effectiveness of the proposed control strategy,to set the controller gains exactly to ascertain certain ratings of few hardware implementation.In this thesis work,real time simulation of a three phase PWM rectifier system with the proposed control strategy has been done using FPGA.
Renewable energy is natural energy which does not have a limited supply and can be used again and again. In recent years, these energies (mostly wind energy) have been one of the fastest growing additions to power networks in many countries. It is due to advance in technology and it''s green nature. But this increase in wind energy might lead to challenging situations concerning reactive power and voltage control issues in both transmission and distribution network. This book, therefore, explains the procedure in extracting the kinetic energy from wind energy via wind turbines and the ability to control these voltage and reactive power issues. With the ability to control voltage and reactive power in wind energy, wind farms will be an ideal source of green energy for 21st century. This book could be useful to professionals who are dealing with wind turbines and green energy technology and to those who are working for the future challenges in power networks.
The text is designed to cater to the need of the students, as well as the research people of on line trade and Economics, by giving a good understanding of the subject and its applications. This new edition seeks to enhance the coverage of the book and update it by including new statistical techniques.It makes the book more comprehensive and incorporates the changes that have incurred in the field of Banking and Management in India as well as the world. The purpose of this book is to clarify concepts of the E-Commerce and at the same time relate them to those examples which rendered the text meaningful to the reader. The book has been written for the student as well as the researcher in the field of Banking and Management, both of whom need to have good understanding of the subject and its applications
Power quality and voltage/current harmonics have been matter of concern in most research on power networks since many years ago. This problem is aggravated in harmonic environment caused by power electronic converters. The harmonic components distort the ac current and voltage at the point of common coupling (PCC) and therefore affects the other adjacent loads connected to the same bus. Excessive reactive power demand increases feeder losses and reduces the active power flow capability of distribution system. Moreover, unbalancing affects the operation of transformers and generators. Presence of power filters using semiconductor switches has proved to be a solution to the electric distribution system facing these problems (reactive power, harmonics, and unbalanced loading). One of the equipment which is used to eliminate such harmonics is active power filter (APF) that is employed in many power networks and industries to suppress the current harmonics generated by nonlinear loads like rectifiers. The major issue related to the effective operation of APF is its controllability to compensate reactive power, harmonics, and unbalanced loading.
This book is based on formal research and evaluation strategy. In the book we have gathered information from different types of iterative process that have been studied in the past i.e. Picard’s iteration, Mann Iteration, Jungck Iteration etc. and have applied the same strategy of their study in a different iterative process i.e. Ishikawa Iteration. So, this book undergoes for an entire new field of fractal analysis i.e. Study of Ishikawa Iteration procedure and to generate its fractal images as well as to derive its fixed points.
Online Optimal Pulsewidth Modulation (OPWM) for a Multilevel Inverter explains a control scheme in controlling a 5-level Cascaded H-bridge Multilevel Inverter (CHMI) output voltage based on the OPWM switching strategies. For better CHMI output voltage magnitude control resolution, a curve fitting technique (CFT) for online computation of the OPWM switching angles is presented. Focus is given on the CFT and the multilevel control design aspect of the control scheme for the CHMI. This control scheme is generally suitable for AC power supply applications that do not involve variations in the multilevel inverter operating frequency. In addition, its suitability is also identified for applications that require high quality output voltage but at the same time do not allow increase in the multilevel inverter power devices switching frequency. This may be due to the technological limits of the power devices employed for high voltage applications or certain environmental condition. To show the feasibility of the control scheme, results of a simulation study and experimental work on a 5-level CHMI operation are presented.
This book does the following: 1- Study different UPS systems, and related subjects such as power electronics, and microcontroller unit. 2- Design and implementation of hardware circuits using microcontroller to get UPS inverter system meets the required performance and do the specified control. 3- Apply classical controllers such as PD, PID, and SMC using microcontroller and simulate these systems on simulation program, after that apply these controllers on the real system, and get experimental results. 4- Apply fuzzy logic control, and nonlinear PID-fuzzy control on UPS inverter system and simulate on simulation program, after that apply these controllers on the real system, and get experimental results.
The Cameroonian grid suffers from transient and permanent overvoltages, voltage dips, harmonics and phase disequilibrium. These problems are faced by many other grids in the world. This led to the invention of the UPS (Uninterruptible Power Supply). As its name indicates, the UPS carries out “Power Processing” on the power signals such that a clean and stable power of high quality is delivered at its output. Unfortunately, most commercial UPS and inverters, especially for off-grid applications, do not have high power ratings. Solar PV off-grid stations have a problem of finding high-power off-grid inverters. This work is aimed at providing a step towards solving this problem. This book is recommended for those interested in the domain of switch mode power supplies. In particular, the reader shall find in-depth analysis of the buck, boost, and h-bridge converters with integrated microcontroller.
In recent years there has been a substantial increase in the demand for controllable reactive power sources which can compensate for large lagging loads. These requirements involve precise and continuous reactive power control with fast response time and avoidance of harmonic line current generation. Solid state Var compensators using forced commutated converters have been developed and are being used for this purpose. Active power filtering (APF) can provide VAr compensation by injecting equal but opposite distortion at selected points in a network. The objective of this project is to design an Active Power Filter (APF) using Voltage Source Inverter (VSI) to achieve reactive power compensation. It is achieved by forcing the inverter line current to follow a reactive sinusoidal reference at a constant switching frequency. The current reference generator has been designed for both lagging and leading reactive power conditions. The reactive power requirements of a bridge rectifier connected load are estimated using the above current reference generator. Using this, an APF is designed to compensate the reactive power requirements of the above load.
This is a case study on Hai-O Enterprise Berhad, the leading traditional healthcare group in Malaysia that has successfully promoted traditional Chinese medicine to a corporate level. It discusses the background of the organization, products, market and its strategies. The case study analyzed Hai-O’s position in the industries and its future plans to take the business further. It also talks about the internal and external environments of the business using different analysis tools which include PEST, SWOT and financial ratio analysis. Based on the analysis, some diagnosis are discussed which further explained the formulation of Hai-O’s vision, mission and objective. And the formulation of Hai-O’s strategies is discussed using different marketing strategy matrix which then further elaborate the organization’s strategies implementation, evaluation and control. Key issues and challenges in the business strategy of Hai-O are discussed in the conclusion part of the case study which evaluates the level of its success.
The project suggests the development of a low cost fuel cell inverter system. The approach consists of a three-terminal push-pull inverter to boost the fuel cell voltage. High-frequency ac link conversion offers a possible way to reduce the number of power stages, in the form of a cycloconverter. The design minimizes overall system cost including energy storage and management. The design provides low-ripple current-controlled interfacing to the fuel-cell stack, an intermediate-voltage battery energy storage buffer, and an ac-link output inverter. The circuit is based on square-wave cycloconverter technology, combined with a simple approach that produces a patent-pending “PWM cycloconverter” modulation process. Modulation technique includes multiple carrier PWM which is a direct extension of conventional PWM. The approach keeps the number of stages and magnetic elements low while providing galvanic isolation. The design provides excellent performance with a minimum filter components and a simple control.
In This book use for Uninterruptible power supplies (UPSs) are widely used to supply critical loads, such as airline computers and life-support systems in hospitals, providing protection against power failure or anomalies of power-line voltage.In general, there are two types of traditional single phase UPSs. The first one couples a battery bank to a half or full-bridge inverter with a low-frequency transformer. In this type of UPSs, the ac output voltage is higher than that of the battery bank; thus, a step-up transformer is required to boost voltage. Due to the presence of the step-up transformer, the inverter current is much higher than the load current, causing high current stress on the switches of the inverter. The transformer also increases the weight, volume, and cost of the systemIn this type of UPSs, the additional booster is needed, leading to high cost and low efficiency. The controlling of the switches in the booster also complicates the system. The dead time in the pulse width-modulation (PWM). The proposed method is also implemented on hardware by using power electronic devices such as MOSFET and PIC controller for production of control signals.