Experimental development of a hysteresis modulated NPC inverter

The paper presents the laboratory prototype realization of a system constituted by an IGBT based neutral point clamped (NPC) inverter, a driver stage and a digital control circuit board. A hysteresis control technique, developed by authors in previous papers, suitable for the current control of the NPC inverter is implemented in the control system. The proposed control technique keeps the advantages of simplest hysteresis controls, i.e., fast response, good accuracy, no knowledge of load parameters; in addition, the modulator can be easily implemented also on a single programmable logic device, requiring quite low hardware resources. After an exhaustive description of the proposed control procedure, the paper set the focus on the realization of the laboratory prototype and presents some significant simulation and experimental results.