Nine-Level Packed U-Cell (PUC9) Inverter Topology with Single-DC-Source and Effective Voltage Balancing of Auxiliary Capacitors

The 9-Level Packed U-cell (PUC9) inverter topology is presented in this paper. It uses eight switches, one DC voltage source and two auxiliary capacitors to generate a 9-level voltage at the output. Obtaining two small size of flying capacitors through proper voltage balancing technique integrated into the modulation unit and without using the complicated external control system that may increase its reliability is the innovation of this article. This topology offers a low-cost inverter compared to the other similar 9-level inverters due to the reduced number of devices and simple voltage controller. PUC9 topology is chosen by trade off between redundancy of states and voltage levels at the output of inverter by selection of suitable proportion of voltage at capacitors than each other and DC source. The stand-alone operation of the PUC9 inverter with implemented voltage balancing technique is investigated through simulation analysis in Matlab-Simulink and results are discussed in details.