DC link capacitor resposne

Question

Dear All,

I made PMSM with the inverter.

I want to see DC-link ripple current and voltage ripple.

But it does not work in my system.

There is an error same as below.

I attached the figure of the circuit.

for the reference, vdc = 660V and each initial capacitor votlage = 330V

 

The model seems to become stiff at this point. For a more efficient simulation please switch to the stiff RADAU solver.

To turn this error into a warning, set the parameter "Stiffness detection" on the Diagnostics page of the Simulation Parameters dialog to "warning".

Answer 1

You can open the Simulation Parameters menu from the Simulation + Simulation Parameters... drop-down.  In the Solver tab you can select different solvers.  Based on your error message you'll want to select RADAU or auto (new as of PLECS 4.5).

You also won't see much DC ripple in your model because your voltage source is directly in parallel with your drive and DC link model.  None of the drive current passes through anything that would cause a voltage drop from the source, so as configured your DC bus model will see a perfect DC source. Something to consider.