Mitigation of Voltage Sag and Swell Using Dynamic Voltage Restorer without Energy Storage Devices

Utilization of Dynamic Voltage Restorer (DVR) to protect sensitive loads against short-term voltage disturbances has been proven to be an aggressive solution in medium- and high-power applications. For low-power applications flirt her cost reductions are required to make the technology even more competitive. Though many works have been proposed for various topologies of DVR almost all the works utilized energy storage devices. Thus the conventional DVR will be more bulky with less power density and need to be maintained in time. The compensation time is also proportional to the rating of the energy storage devices. As the compensation duration increases the size the conventional DVR also increases. The DVR model is replacing the conventional AC-DC-AC converter by a Matrix Converter thus avoiding bulky energy storage devices and able to compensate for indefinite time with very high power density The DVR is connected between the source and the load. The matrix converter based DVR circuit requires only four bi-directional IGBTs. Pulse Width Modulation (PWM) technique is adapted for the synthesis of switching pulses to control the switches. The circuit model for matrix converter based DVR system is developed using matlab simulink to perform simulation studies. From the simulation results it is observed that the DVR is able to compensate voltage sag of 50% and swell of 100% with the THD less than 5%. Experimental results of a 1500 VA, 230 V, and 50 Hz laboratory prototype is presented. Copyright (C) 2012 Praise Worthy Prize S.r.l. - All rights reserved.