3630

3429

كارشناسي ارشد

قدرت

اصفهان : دانشگاه صنعتي اصفهان ، دانشكده برق و كامپيوتر

1386

ده ، 125، [II] ص : مصور ،جدول ، نمودار

ص.ع . به فارسي و انگليسي

محمد اسماعيل همداني گلشن

محمد ابراهيمي

8/5/86

مهندسي برق و كامپيوتر

ID3429

به فارسي و انگليسي : قابل رويت در نسخه ديجيتال

AbstractDynamic Voltage Restorer DVR is connected in series with the distribution network in order tocompensate the load voltage by the fast injection of suitable voltages to the system The merits ofDVR are the fast dynamic response and lesseer power rating than the load power so it is aneconomical choice for the sag compensation The DVR control block determines magnitude andphase angle of the injected voltages through using some control algorithms In this thesis after areview of the previous researches balanced and unbalanced voltage swells are simulated forinvestigating the influence of three compensation strategies inphase presage and minimum energyon energy storage devices during the voltage swell Then saving energy method consisted ofminimum energy maximum energy and zero injected power strategies is introduced This methodis based on choosing the proper injected voltage angle to control the voltage across the dc linkcapacitor A supervisory control scheme is introduced as the outer control loop that can improvecompensation capability of DVR during serious voltage sags and swells Finally DVR iscompleted by a proper protection scheme that prevents from flowing dangerous currents into DVRwhen a fault occurs in down stream of DVR After design simulation and investigation of dynamicresponses of a simulated DVR a laboratory DVR rated at 3KVA and 230V was designed andimplemented Since real time data processing and simultaneous application of control algorithmsand switching pulses generation are required a digital signal processor board with fast processingand information interchanging abilities was employed All necessary circuits including analog todigital converter isolation between power circuit and digital circuit IGBT drivers dead bandgenerator 15 volt power supplies injection transformers and low pass filter were designed andimplemented In addition a voltage sags and swells generator was designed and implemented fortesting the DVR performance This device can generate sag and swell with one cycle to threeseconds intervals Experimental results show that the implemented DVR is able to compensatevarious voltage sags and swells in less than few milliseconds after occurrence of disturbance

محمد اسماعيل همداني گلشن

محمد ابراهيمي