How does a true sinewave inverter work

igbtinverterpowerpwmsine

I am an Electrical Engineering student, and when we were taught about inverters (at a power electronics course) we studied inverters using Sinusoidal Pulse Width Modulation.

My question is do the so-called "true sinewave" inverters use the same technology, or a different one?

Isn't it possible instead of using SPWM to directly create a sinusoidal waveform (stepped like a DDS signal generator does) and then use that waveform to drive some power semiconductors?

Best Answer

You could, but the SPWM technology, as you call it, allows the use of "class D" (digital switching) power technology, which is much more efficient than any sort of linear power amplifier would be.