AC Sweep for three phase inverter

I’ve watched the tutorial on “Inverter design with average current and voltage loop control” I’m trying to perform an ac sweep of a three phase inverter. I’m using the SPWM method.

I’m not getting smooth curves for my phase and amplitude curves so I wanted to confirm if my ac sweep is correct. I am using the sinusoidal perturbation with a summer and sine wave inputs. The original simulation works fine. The dc input is 30Vdc with an output voltage of 15Vpk. I’ve set the amplitude of the perturbation as 15Vpk and set the source amplitude of the perturbation in the multisine block as 10%. So I’m not why I’m getting erroneous results.



please have a look at the attached. It has been modified.


  • set all fundamental Vma frequencies to 0.8 as the carrier waveform is +/- 1V. The fundamental + perturbation amplitudes must be less than the carrier waveform peak to peak, your original simulation exceeds this limit.

  • set to ‘0’ all phase perturbations except for phase A. With which I ran a test with a small amplitude to ensure good simulation.

  • edited the sweep setup block. start frequency 10Hz end 5KHz, and set the perturbation amplitude to 0.08 which is 10% of the amplitude of Vma which is 0.8.