High performance current control techniques for applications to multilevel high power voltage source inverters

Several high-performance current-control techniques have been developed for applications to multilevel high-power voltage source inverters. The logical sequence of the design choices is described. They result in a very robust and reliable control system that allows an adequate switching optimization and excellent dynamic responses. The advantages of using various accessible DC potentials have been fully exploited. The results obtained by digital simulation refer to five-level voltage waveforms, but the current-control strategies developed can easily be applied to any multilevel inverter structure, even in the case of n-level voltage waveforms. The validity of the proposed schemes has been confirmed by both digital simulations and tests carried out on scale models