Hi,
Let me see if I can answer the questions in order.
1) At the three-phase sources, you set delay to create phase shift between them. What does {1/1200} and {2/1200} mean? I also tried to modify the sources by removing delays and setting phase #2 to have 120° phase shift and phase #3 to have 240° phase shift, but this did not work, I am getting some strange voltage spikes on phases ... why?
The contents of the curly brackets are calculated before the simulation starts.
The expression 1/1200 is a fraction indicating 833.33333333 us.
it comes from calculating a 120 degree delay at 400Hz into time:
120 degrees = 1/3 of cycle
1/3 * 1/400 = 1/1200
If you want degrees you could write the expression
{degrees / 360 x frequency} that {120/360*400}
The delays are from the start of the simulation, t=0
.
2) V1 ... What does 1530u delay do? I don't understand. I understand that Ton (830u) represents approximately 1/3 of the period at 400Hz, which corresponds to 120°, am I right? Is it possible for all other pulse generators to set phase dependencies between them rather than delays? I don't understand {6/2400}, for instance ... could you explain this also?
1530us corresponds to 220 degrees at 400Hz. It is used to align the output of the main pulse generator with the ac source. 210 degrees is the start of the conduction, the extra 10 degrees is a time before the MOSFET channel is turned on
3) Where exactly can I see how the voltage across the MOSFET switches between diode and the channel? Which parameters do you suggest to especially pay attention to when MOSFETs conduct more than 120°?
By looking at the steps in the voltage across the MOSFETs. When the voltage is around 0.7V the body diode is conducting. When the voltage is lower the body diode is conducting.
4) Is there a way (like a meter) to measure power on both AC and DC side, so I could calculate efficiency?
You can add .meas statements to the model like this:
I have changed the simulation directive to .tran 0 120m 20m This means ignore the first 20ms of data. This allows the system to settle before making measurements.
To see the results from the measurements, View and then SPICE Error Log. You will something like this:
This is the model with the changes:
I have attached the model.
Regards,
Jay_Diddy_B