Deadbeat Current Controller Design for Multilevel Grid Connected Inverter

This paper presents a three-phase hybrid multilevel converter (MLC) topology for photovoltaic (PV) grid-connected system with a new current control scheme. Deadbeat current controller in α-β reference frame is designed in S-domain using derivative feedback to make the actual current to track exactly the reference current. The controller generates α-β reference voltage for inverter with lower power electronic components. The inverter has high quality output voltage which leads to a high quality injected grid current thus eliminates the using of custom and more expensive power filter for the high power rating systems. Besides, MLC switching losses is very low due to most of the power cell switches are operating at nearly fundamental frequency. Some selected simulation results are presented to validate the proposed system and the proposed control scheme.