Monograph, The Ohio State University, USA, 2005, pg. 190Along with the growth in demand for electric power, sustainable development, environmental issues, and power quality and reliability have become concerns. Electric utilities are becoming more and more stressed since existing transmission and distribution systems are facing their operating constraints with growing load. Development in technology has been making the whole society more and more electricity dependent and creating more and more critical loads. Under such circumstance, distributed generation (DG) with alternative sources has caught people’s attention as a promising solution to the above problems.
A dc/ac voltage source inverter (VSI) is the most widely used interface for DG units, which involves many topology and control aspects under different operating conditions. Only with satisfactory control performance of each individual unit can paralleling two or more inverters or connecting one or more inverters to the power system be conducted which involves P and Q control under various local load char-acteristics and operating conditions.
As stated above, the tremendous complexity in the power electronics interfaces for DG units creates many research problems as well as many possibilities to advance technologies. Many of the problems have been solved or partly solved while many are still left unsolved or even unfound. In general, a practically functioning DG system has to properly solve possible technical problems in the following three categories - control of a single inverter unit with quality voltage output in island mode, control of line real and reactive power flowing between a DG unit and the utility grid in grid-connected mode, and control of front-end power generation or conversion for high performance and low overhead.CONTENTS:
Introduction
Voltage and current control of a three-phase four-wire DG inverter in island mode
Power flow control of a single distributed generation unit
A PWM rectifier control technique for three-phase double conversion UPS under unbalanced load
Conclusions
Bibliography
