# Isolated three level pwm LTSPICE

I am doing a simulation on LTSpice of a three level ANPC. The ground is connected to the neutral point (i.e in the middle point of the DC input) and the gate drivers are isolated by using a DC DC converter (so the voltage is floating). The thing is that I need to gate the transistors and I have the modulation done with signals that go from 0 to 5V.

I did this signals by using BV sources connected to the common ground: one carrier that goes from 0 to 0.5, another that goes from 0.5 V to 1V and the modulating sine in the middle.

How can I impose the PWM to the input of the gate driver? How should I shift the signals to the source level of the transistors?

• I normally cheat with the e-function. Set gain to 1 and it will provide indefinite speed and isolation. – winny Jun 17 '18 at 21:58
• See this answer for a possible solution to your case, and to get an idea on a simplified way to simulate what you want, faster. – a concerned citizen Jun 18 '18 at 6:10

bv=V(pwm)*V(gatesignal)+V(whatever)