Controlled drive can be DC or AC. Drive's converter is ideal.
DC-DC converter is fed by ideal voltage source. DC-DC converter provides DC-link voltage stabilization on a constant level.
The easiest way to calculate instantaneous DC-link current is idc = Pdc/Vdc, where Pdc, Vdc are DC-link power and voltage, respectively. Pdc can be calculated based on motor operation.
If we take into account drive's converter, we could calculate idc using duty cycle of each phase and phase currents, still duty cycle is bound to Vdc.
This division makes current idc dependable on Vdc, which complicates the DC-link voltage control and may lead to instabilities.
Is there any other way?
do you want to measure the current in the simulation? why don't use of current measurement block?
Hi, Yevhen,
Why do you need the DC-link current?
Which DC-link current you would like to know more about?
Current between the DC-DC converter and the DC-link capacitor, or current between the DC-link capacitor and the drive converter?
As you probably know, both of those currents are highly discontinuous, but they can be reconstructed by measuring the DC source or drive's current(s) and taking into account gating signals.
In other words, if you know which transistor is driven and if you know the load or source current waveform (sign and value), you can easily reconstruct the current that is injected or taken out of the DC-link capacitor.
Also, estimating the DC-link current by using idc = Pdc/Vdc expression will give you the (instantaneous) average DC-link current, not the instantaneous current value/waveform.
Regards,
Ivan.
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