A pulse width modulation technique for a multilevel converter in high voltage high frequency applications

In this paper, a new hysteresis voltage control technique based on optimized harmonic elimination method is presented for a single phase multilevel inverter with flying capacitor topology in high voltage high frequency applications such as high voltage plasma systems. A main objective of the proposed technique is to generate high voltage and control capacitors voltages in all operational conditions. For this purpose, principals of optimized harmonic elimination technique with and without considering switching time are described by mathematical analysis and simulation results. Then, a hysteresis voltage control is analyzed in detail to control capacitors voltages when load impedance changes significantly due to nonlinearity of load such as a plasma reactor. A 100 times decrease in load impedance is simulated and flying capacitors voltages are controlled without any voltage collapse.