Single-phase three-level SPWM scheme suitable for implementation with DSP

A half cycle wave inversed based dual reference modulation three-level SPWM (TLSPWM) scheme is proposed. To avoid the switching of the compare logics between reference modulation and carrier, two reference modulations are applied in the negative half cycle of reference modulation. One is obtained by adding the amplitude of the carrier to normal reference modulation, the other is obtained by adding double the carrier amplitude to normal reference modultion. Thus, the three-level SPWM waveform is implemented using only one element government (EV) in DSP, and the attached logical circuit is no longer needed. The experimental results prove the accuracy and feasibility of the proposed SPWM scheme.