An Introduction to Wavelet Modulated Inverters

Book Preface

Power electronics has emerged as the enabling technology for industrial competitiveness in the world marketplace in the 21 st century. One of the most valuable achievements in power electronics is the introduction of degree of freedom to variable frequency in order to produce electric power with the least environmental consequences, keep the power system stable, improve products and services, and minimize energy wastage, as well as enhance power quality and improve efficiency. The industry standard approach has been the carrier – based pulse width modulation (PWM), which is based on generating the switching pulses through comparing a high – frequency carrier signal with a low – frequency sinusoidal reference modulating signal. The general objective of dispensing with the carrier signal altogether has been successfully realized by the non – uniform sampling – reconstruction process, which is supported by a non – dyadic multiresolution analysis structure of the modulating signal. Such a dc – ac power electronics converter is called the wavelet modulated (WM) inverter. The salient feature of the WM inverter is its ability to increase the magnitude of the fundamental component and to reduce the harmonic components from their outputs. This feature is evident from close – to – ideal sampling reconstruction of the sinusoidal reference modulating signal using the scale – based linearly combined scaling and synthesis scaling functions. The wavelet modulation technique generates the inverter switching signals without the need for a carrier signal, precalculated switching times, or a linear range of modulation indices simplifi es the implementation process. As a result, the wavelet modulation technique minimizes the memory requirements and lowers the computational burden along with insensitivity to the implementation platform. The new wavelet modulated inverter is systematically presented in this book. The introductory chapter briefl y presents the fundamental topologies and operation of power inverters. The second chapter describes wavelet basis functions and sampling theory with particular reference to the switching model of inverters. Chapter 3 outlines the connection between the non – uniform sampling theorem and wavelet functions to develop an ideal sampling – reconstruction process to operate an inverter for obtaining its optimal performances. The scale – based linearly combined basis functions are developed in Chapter 4 in order to successfully operate single – phase wavelet modulated inverters. Chapter 4 also describes the development of the non -dyadic type multiresolution analysis, which are responsible for sampling and reconstruction of three continuous time reference modulating signals for three – phase inverters. The performances of single – phase wavelet modulated inverters for static, dynamic, and non – linear loads are presented in Chapter 5 , while Chapter 6 contains the simulation and experimental performances of three – phase wavelet modulated voltage source inverters for different loads at various operating conditions.

This book presents the latest technology in the advancing power electronics field. It serves as a new reference for academic researchers, curious engineers, and other professionals. The book also provides pertinent technical background for a text or reading book for a graduate – level course in advanced power electronics. The authors acknowledge the contributions of graduate students, post – doctoral fellows, faculty, and staff at Memorial University of Newfoundland and Tokyo