الفهرس 
INTRODUCTIONOnly 14 pages are availabe for public view
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Abstract
The importance of the power quality (PQ) in the electrical distribution system increases specially for sensitive loads. The voltage disturbances such as sags(dips) and swells are the most common power quality problems, these issues causing financial losses. The starting current of large induction motors, the faults in grid and the reclining of the circuit breakers are considered the main sources of the voltage sags. Dynamic voltage regulator (DVR), one of the most important power devices, has been used to protect sensitive loads from these voltage disturbances. Conventional DVR injects the required voltage in series with the line through an injection transformer to maintain load voltage at the desired value. However, several problems namely cost, weight, and losses related with the series injection transformer make the application of conventional DVR undesirable at places like homes, offices etc. To overcome these problems of the conventional DVR, proposed transformer-less DVR scheme with lower cost, weight, size, and losses is presented in this thesis. In this thesis the proposed DVR consists of only storage unit and multilevel inverter (MLI) which has two stages, each stage based on only six power electronic switches with total harmonic distortion in nominal range in the output waveform. It presents a transformer-less DVR that can recover the voltage disturbances to that the same magnitude and phase angle before disturbance occurs. The model of the proposed DVR is designed by using the MATLAB/Simulink and PSCAD/EMTDC software. Simulation results are discussed, the performance of the proposed DVR system under different types of voltage disturbances is demonstrated in the simulation results. With the help of the dSPACE (DS1104) evaluation board, the prototype of the proposed DVR has been constructed and tested in laboratory. The experimental setup and hardware implementation are described. The experimental results for the proposed topology are included and discussed.