| Title |
Quasi Z-Source Dynamic Voltage Restorer by a Simple Duty Cycle Control Scheme |
| Authors |
Jun-Hyun Eom ; Young-Gook Jung |
| DOI |
http://doi.org/10.5207/JIEIE.2021.35.6.026 |
| Keywords |
Compensation voltage; Four quadrant voltage control; In phase buck mode; Quasi Z-Source dynamic voltage restorer(DVR); Simple duty cycle control; Voltage sag swell |
| Abstract |
The quasi Z-source dynamic voltage restorer using the conventional switching scheme was able to obtain only the compensation voltage in the out of phase buck-boost mode for voltage swell compensation of the power source and the in-phase boost mode compensation voltage for more than 50% voltage sag compensation. Since this method cannot compensate for the voltage sag of 1-50%, which mainly occurs in industrial fields, a method of connecting additional quasi Z source converter in series and parallel was studied. In this study, a simple duty ratio scheme was proposed which is can be operated as an out of phase buck boost mode to compensate for swell, an in-phase boost mode to compensate for sag of 50% or more and an in-phase buck mode to compensate for sag of 1-50%. In order to prove the validity of this study, PSIM simulation and DSP based experiment were performed. As a result, by the proposed duty ratio control scheme, it was possible to compensate both the in-phase buck boost mode and the out of phase buck boost mode for sag and swell with a single quasi Z-source dynamic voltage compensator. Finally, for each load of 50 and 100 even if the voltage sag and swell were generated step by step by 10%, the voltage compensation rate remained almost 1, and the THD of the voltage was all good at 5% or less. |