Three-level hysteresis band modulation strategy for single-phase PWM inverters

A novel three-level adaptive hysteresis band modulation strategy for single-phase inverters is presented. It is shown that the total harmonic current distortion of the new strategy closely approximates that of the off-line precalculated harmonic minimised PWM switching angle solution sets. It is shown that the three-level adaptive hysteresis band strategy can be defined using a modulation process possessing both pulse-width and pulse-position modulation. Two strategies are presented to determine the switching angles in one quarter of the fundamental period of the PWM and the advantages of each method are discussed using a digital signal processor implementation. Both simulation and experimental results for the three-level adaptive hysteresis band PWM strategy are presented to confirm the theoretical analysis.