Delta-sigma modulation applications in neutral-point clamped inverters

Delta-sigma modulators have been successfully applied to over-sampling digital-to-analog and analog-to-digital data converters. In addition, investigations have been pursued in power electronics applications such as switch-mode power supplies and switch-mode inverters. In this paper, delta-sigma modulation is investigated and applied to three-level neutral point clamped voltage source inverters. The high switching frequency power spectra density, common mode voltage reduction and low average switching frequency are discussed. The simulation results show that delta-sigma modulation can effectively reduce the magnitude of the switching frequency power density, increase the efficiency of the inverter and lower the common mode voltage. Experimental results substantiate the simulation results.