Seven-Level Inverter With Self-Balanced Switched-Capacitor and Its Cascaded Extension

A switched-capacitor based seven-level inverter is proposed in this work. It consists of two capacitors, two diodes, and eight transistors. The eight transistors form two H-bridges resulting in a simple structure and easy design of gate drivers. Capacitors' voltages are balanced automatically as they operate in parallel with the input voltage source a few times during each cycle of output voltage. Voltage ripples and power loss are analyzed in detail. To obtain more output levels, the cascaded structure of the seven-level inverter is also investigated and a power balancing strategy is used to simplify design work. Finally, the effectiveness of the work is experimentally demonstrated by both the seven-level and 13-level prototypes. It indicates that the proposed inverter is capable of powering different types of loads, and its efficiency is up to above 97%.