High Performance Digital Hysteresis Control for Single Source Cascaded Inverters

A digital modulation technique for cascaded inverters, which allows achieving high performance with low power losses, is proposed in this paper. It consists in a variable slope-fixed band current hysteresis control applied to a cascaded voltage source inverter structure, fed by a single dc source. The proposed technique can be used to supply ac motors, as well as generic ac loads. A considerable reduction of the switching losses is achieved, without increasing the total harmonic distortion on the load side. This result has been validated by means of a preliminary numeric analysis and confirmed by an experiment implementation.