Power Flow Control of Grid-Connected Single-Source Multilevel Converter with DC-Link Voltage Control

In this paper, the closed-loop control architecture for a single-source multilevel inverter (MLI) is presented in order to regulate the dc-link voltage and power transfer to the grid. The MLI topology consists of a diode-capacitor voltage multiplier circuit to obtain several self-balanced capacitors voltages. The adopted control technique allows the decoupled control of active and reactive power injected to the grid at almost unity power factor and reduced total harmonic distortion. The proposed MLI serves a dual purpose, i.e., boosting the input voltage with a high boost ratio and inverting action with multilevel output AC voltage. A 500 W laboratory prototype of the proposed converter was built with the closed-loop control. The performance of the grid-tied MLI was investigated in different real time scenarios and the experimental results are presented to demonstrate the performance of the closed-loop control architecture.