Cascaded H-Bridge Multilevel Inverter with Reactive-Power Compensation for Single-Phase Grid-Connected System

This paper presents the power factor compensation of a grid-connected system using a five-level cascaded H-bridge multilevel inverter (FCHMLI) supplying real power and reactive power (pq-power) to the grid system. The FCHMLI output power is controlled using a vector control based on the dq-axis synchronous reference frame technique. This methodology can control the pq-power between the FCHMLI and the grid system that can inject or absorb independently. The real power and reactive power can be controlled independently with d-axis and q-axis currents, respectively. The grid system is connected with the resistive and inductive loads that provide the lagging of grid power factor. The proposed technique has been simulated by MATLAB/Simulink program in order to verify the correctness of the proposed control scheme. The simulation results are found the FCHMLI can inject not only real power but also the reactive power to improve the grid power factor associated with linear loads resulting in near unity power factor.