Voltage Sag, Swell, and Interruption Mitigation Using a Fuzzy Logic-Based DVR with Energy Storage Integration

Voltage sags, swells, and interruptions are the most critical power quality issues, frequently affecting sensitive loads. While most DVR systems in literature use controllers like P, PI, PID, fuzzy logic, or neural networks, this study proposes a controller-free DVR solution. The system includes a Voltage Source Inverter (VSI), LC filter, series transformer, control circuitry, and a battery bank, positioned after the distribution transformer.Supply voltages are measured and transformed into DQ0 components. If voltages are normal, no PWM is generated, and the DVR injects zero voltage. During disturbances, error signals appear in the DQ0 frame, are transformed back into three-phase signals, and used to generate switching pulses. The VSI then injects a compensating voltage via the series transformer to maintain rated load voltage.MATLAB/Simulink simulations confirm that the DVR effectively compensates for 100% balanced/unbalanced sags, swells, and both single- and three-phase interruptions.