A novel load side compensation for voltage sag / swell using dynamic voltage restorer [articol]

Abstract

Power quality is one of major concern in modern era and has become important with the introduction of very advanced devices, whose performance is very sensitive to the quality of powe r supply. Power quality problem such as non standard voltage, current or frequency leads to equipment failures of end user. The major power quality problems are voltage sag, swell and harmonics. To solve this problem, custom power device called Dynamic Vo ltage Restorer (DVR), which is the most efficient and effective modern device used in the power distribution networks. The objective of the proposed DVR is to compensate the voltage sag, swell and harmonics by load side compensation. To compensate the vol tage distortions for long duration, DVR without energy storage and load side connected shunt converter topology is proposed. Based on this topology, the DVR consists of uncontrolled rectifier for giving DC supply to Z Source converter through DC link. Z Source Converter based topology is used in order to enhance the voltage restoration property of the device. The control of shoot through capability of Z Source Inverter using IGBTs provide s ride through capability during voltage sag and swell , which incre ases its reliability. A control scheme called Hysteresis Voltage loop controller is proposed to synthesis the desired injecting voltage. Simulation and experimental results are provided to demonstrate the validity and the features of the proposed novel met hod.