switching and coduction losses of a three phase converter

Question

The goal of the simulation is to simulate the switching and conduction losses of a 3-phase converter. The converter should be operated without load. The following aspect is not clear to me:

Why are the switching losses so high? According to the parameterization the losses at maximum collector current (Ic = 4800A) should only be about 2.5J (see appendix).

Can anyone help me or point out errors in my simulation?

Appenix:

Simulation model, initialization file (Matlab), thermal model IGBT and diode and an extract from the data sheet of the IGBT

Answer 1

Hello,

Looking at the graph you attached, let's just say during each switch-on event the IGBT dissipates 1J. However, since your switching frequency is set to 1MHz, you will have 1MW of losses during a 1 second window of time. So I believe you need to greatly reduce your switching frequency to see more realistic switching losses. And anyway, an IGBT is likely not designed for such operation, but rather to be switched in the 10's of KHz.

Kris