Multifunctional DVR With Seven Level Inverter Scheme Using Voltage and Current Control

Voltage sag is a very crucial issue faced by the modern electrical industry which has resulted in increased attention. . Voltage sag is defined as a decrease in voltage from 0.1 to 0.9 per unit (pu) in rms voltage at the power frequency for durations from 0.5 cycle to 1 min. It is mainly due to the energization of heavy loads or starting of large induction motors changeover of large loads etc. Other major issue that our utility mainly deals is short circuit faults like single phase to ground, two phase to ground or three phase faults. It cause to flow a large current through the unfaulted phase and decrease in voltage in the affected phase. So inorder to eliminate those two problems we use multifunctional DVR. It is a power electronic converter based custom power device used to compensate for voltage variations and to limit the fault current. This study proposes a new scheme for multifunctional DVR based on a seven level multilevel inverter and a different control scheme. This results in better quality of output voltage in voltage sags. It is important to emphasis that the existing inverter-based DVR topologies do not have the capability of third harmonic elimination, Consistency in DC link voltage, Better output for inverter section, efficient modulation scheme incorporation etc. The system model is carried out in MATLAB/SIMULINK environment. With the aids of the proportional-integral controllers, dq0-abc transformation Level shifted pulse-width modulation control technique, the inverter control system is managed.