Hi all,

I have designed a control circuit for single phase soft starter and its setting as below:

Basic control circuit:


Setting:


Vrms output:


I wonder why there is stair shaped appeared on the Vrms output. As I use a linearly increasing ramp compare with the triangular waveform, why the Vrms output is not linearly increasing before reaching full voltage?

Is this circuit consider as a soft starter? and any further improvement i can make on this circuit?

Thank you for your help.