New staircase sinusoidal voltage synthesizer and optimal interval type-2 fuzzy controller for dynamic voltage restorer to compensate voltage disturbances

In this paper, a new staircase sinusoidal voltage synthesizer based on dc-dc boost converter and dc-ac multilevel inverter is proposed for dynamic voltage restorer to accurately compensate the power quality issues. The dc-dc boost converter which is connected to photovoltaic-based power supply system can provide required energy and high-gain voltage [2*(1−K)⁻²] via tracking the maximum power for the compensation process. The dc-ac multilevel inverter which their dc power sources have followed septenary geometric progression can provide high step staircase sinusoidal voltage [7^(Nsw/6)] with low switch count. In this regard, the proposed staircase sinusoidal voltage synthesizer can effectively compensate the voltage disturbance conditions. In view of the fact that the compensator control system must properly operate so that the proposed voltage synthesizer reveals its step creation capability, an interval type-2 fuzzy controller is implemented to assist the power electronic part. The controller parameters have been optimally extracted using multi-objective stochastic fractal search algorithm to ensure the control process accuracy. To verify and validate the compensation capability of the proposed compensator, the simulation results have been focused on asymmetrical voltage disturbance conditions. Finally, the comparison and simulation results have strongly confirmed the high step creation and compensation capabilities of the proposed DVR.