A New Concept of Multilevel DVR based on Seven-Level Packed U-Cell Inverter to Improve Power Quality

This paper proposes the mitigation of grid voltage disturbances using a 7-level Packed U Cells (PUC7) based dynamic voltage restorer (DVR) solution . Which regulates the injection of the compensation voltage in series and synchronism with the grid during the voltage disturbance events, the auxiliary capacitor voltage, while controlling the PUC7 output current. A Seven-Level Packed U Cells (PUC7) inverter is composed of a smaller number of IGBTs and circuitry compared to similar structures. A voltage balancing controller is designed to apply the seven levels of the inverter; this is done by regulate the output voltage of the DC capacitors to a desired value in order to obtain seven levels at the output of the inverter. This feature enables the structure to be used to compensate for the power quality of power distribution networks. Nearest Level Control (NLC) in the inverter is used to create the desired waveform. The In-Phase control method is selected to control the proposed DVR and use the synchronous reference frame (SRF) method to detect the network voltage fluctuations. To verify and validate the proposed DVR performance, simulations are carried out in the MATLAB / SIMULINK software environment, and the results indicate the optimal performance and desirability of the proposed DVR to compensate for the voltage sag, swell and flicker power distribution grids. Theoretical analysis and simulation results are given to show the high performance of the proposed solution.

کلیدواژه ها:

Packed U Cells Inverter ، DVR ، Multilevel Inverter ، NLC switching ، Voltage Compensation.