TRAN:timestep too small trouble with diodes included in the circuit

[Forvergoon]

Hi everybody!

     I have been simulating a inverter using Multisim9. The simulation went smoothly and the results were nice yesterday with the DC voltage of 400V,   the IGBTs and the Fast Recovery Diodes are IRG4BC10U7 and 1N5406 respectively. However when the DC voltage is 1000V, the IGBTs and the diodes are IRGPH50M and MUR810, the simulation seems to have some problems with the diodes according to the error message given by he software. I have tried everything I can do to solve this problem, but unfortunately these work are totally in vain.

    And the circuit is in the attachment, can anyone give me some advises? Thank you in advance and look forward to your reply.

                                                                                                                                                                                          Moon

[Fernando_D]

Hello,

The reverse breakdown voltage for the MUR810 is 100 V, you are exceeding the rating of the diode.

Regards,

[Forvergoon]

Hello Fernando!

      Frankly speaking I had noticed this error since the moment I uploaded this question, and later I changed the diodes the simulation went smoothly. But the simulation sometimes would suspend if I change some elements' parameters, while I have to change some values to get the best performences. I do not know why and this is the real tough problem.

      Thank you all the same.

     Regards!

                                                                                                                                    moon