Modeling and Control of a Novel Transformer-less Dynamic Voltage Restorer Based on T-type Multilevel Inverter for Power Quality Improvement

This paper presents T-type multilevel inverter topology-based dynamic voltage restorer (DVR) with reduced switch count. In medium voltage and high-power applications, two-level voltage source inverters are insufficient because of more voltage stress on switches, large dv/dt, size, and cost of the filter. To overcome these problems, multilevel inverter-based DVR is suitable, which can be directly connected to the medium voltage distribution system without injection transformer. Nearest Level Control (NLC) in the inverter is used to create the desired waveform. The instantaneous reactive power theory (IRPT) to control the proposed DVR, The IRPT control scheme is famous by the name of p–q transformation. Clarke coordinates transformation is the base of this scheme It is applied to the voltage and current to represent in polar form. 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 Unbalanced in power distribution grids. Theoretical analysis and simulation results are given to show the high performance of the proposed solution

T-type Multilevel Inverter, DVR, IRPT, NLC switching, Voltage Compensation