PWM techniques for matrix Converters investigations and applications

Abstract

The Matrix Converter is an attractive topology of power converter newlinefor variable speed AC drive applications, which converts the AC to AC in a newlinesingle stage. The advantages of the matrix converter are its capability of newlineproducing a variable output voltage with unrestricted input and output newlinefrequency, the absence of electrolytic capacitors, and the potential to increase newlinethe power density, reduced size, reduced weight and better input power newlinequality. However, industrial applications of these converters are limited newlinebecause of some practical issues such as complex control strategies, high newlinesusceptibility to input power disturbances, common mode voltage effects and newlinelow voltage transfer ratio. Recently, matrix converters have experienced a newlineresurgence of attention due to the advancements in the semiconductor device newlineindustry and the growth of processor technologies, which promises practical newlineimplementation of matrix converters in the control of drives. This dissertation proposes several new matrix converter topologies newlinetogether with their control strategies to provide a solution to some of the newlineabove issues. Two novel and simple matrix converter modulation techniques newlineare proposed. The first one is based on the error integration method, referred newlineto as the Minimum Error Switching Strategy (MESS) and is particularly newlinesuitable for a matrix converter at high switching frequencies. The second one newlineis based on the carrier pulse width control, referred to as the Decoupled newline Indirect Duty Cycle (DIDC) PWM technique. This scheme does not calculate newlinethe duty cycle explicitly and extracts the duty cycle information from the newlineavailable reference signals. In addition, a simple carrier frequency adjustment newlinetechnique is proposed to improve the nature of input current. The technique is newlineparticularly suited for real time-implementation of the matrix converter. The newlinepractical implementation of the DIDC PWM method using FPGA Spartan 3E newlineis also presented.