@article{article_97515, title={Four-wire Solid State Transformer to Improve Current Quality}, journal={Gazi University Journal of Science}, volume={25}, pages={887–899}, year={2012}, author={Banaei, Mohamad Reza and Salary, Ebrahim}, keywords={Four-wire solid state transformers, neutral wire current, Current harmonics and unbalances}, abstract={<p class="MsoNormal" style="line-height:150%;margin:0cm 42.55pt 0pt;"> <a> <span> <span> <span> <span> <span style="font-family:’Times New Roman’;font-size:small;">Solid state transformers </span> </span> </span> </span> </span> </a> <span style="font-size:small;"> <span style="font-family:’Times New Roman’;"> <span> <span> <span> (SST) are used to perform typical functions and improve power quality in series operation of three-phase power systems. Generally, current harmonics and unbalances and neutral wire current are generated due to nonlinear, unbalance load and supply voltage distortion. In this paper operation of three-phase four-wire SST to improve current harmonics, current unbalances, neutral wire current and reactive power of nonlinear load as an active filter synchronous by feeding linear load is analyzed and </span> <span lang="en-gb" xml:lang="en-gb">application of AC/DC converter with four legs and it’s controller to compensation of neutral <span> wire current and current quality </span> in the input stage of SST is investigated. </span> </span> </span> <span> <span> <span> Power quality improvement with SST has been verified by simulation results using MATLAB/SIMULINK. The results show that SST and its controller has very good performances, and it can not only realize the functions of series operation, but also can prevent from harmonics injecting and unbalances by parallel operation. <span>Besides, proposed controller makes neutral wire current of voltage source becomes almost zero i </span>n four-wire distribution system. </span> </span> </span> </span> </span> </p>}, number={4}, publisher={Gazi University}