Fuzzy Logic-Based DVR Using Energy Storage Devices for Compensation of Voltage Sag, Swell, and Interruptions.

Although there are many power quality problems, voltage sag, interruption, and swell are thought to be the most significant since they happen frequently and negatively impact sensitive loads. Despite the fact that there are numerous DVR topologies described in the literature, all of them use fuzzy or neural network controllers, P or PI, PID, or some combination of these to address power quality concerns. However, this study demonstrates that Dynamic Voltage Restorer (DVR) can be used to reduce voltage sag, swell, and outages without the need for controllers such as P, PI, PID, fuzzy, or neural networks.  The Voltage Source Inverter (VSI), control circuitry to produce switching pulses, an LC filter, a series transformer, and a battery bank for energy storage make up the suggested DVR. To safeguard the load against variations in supply voltage, the suggested DVR is attached just after the distribution transformer. To produce error signals, the three-phase supply voltages are always measured, transformed into Direct-Quadrature-Zero (DQ0) quantities, and then compared to the reference value. The error signal is zero when the supply voltage is at its rated value. Therefore, the control circuitry won’t produce PWM, and the VSI won’t produce any compensatory voltage. In this scenario, a breaker will also be used to short circuit the series transformer’s secondary winding. Thus, the DVR injects zero voltage into the line. As a result, the supply and load voltages are equal and kept at their rated values. The three phase voltages are not at their rated value and are also out of balance whenever there is a supply side sag, swell, or interruption. Error signals will therefore be produced in the DQ0 frame. Using the inverse DQ0 transformation, these error signals in the DQ0 frame are once more transformed into three-phase voltages. Switching pulses are produced for the VSI using these three-phase error signals. To keep the load voltage at its rated value, the series transformer injects the generated compensating voltage along with the supply voltage. The results of simulations conducted using MATLAB Simulink software confirm that the suggested DVR is capable of mitigating 100% balanced and unbalanced voltage sag, 100% balanced and unbalanced voltage swell, single phase outage, and three outages.