3 phase rectifier - LTSpice simulation

Thread Starter

Skeebopstop

Joined Jan 9, 2009
358
I have simulated the attached circuit single phase with no issues and expected results, but when I hook up the full 3 phase bridge like this, LTSpice vomits and my capacitors sees kiloAmps of load?!

Must be something obvious I am missing?
 

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ifixit

Joined Nov 20, 2008
650
You need to select a diode model. Right-click on the devices and pick a suitable one from the list... the MUR460 (600V, 4A) will likely work in the simulation, however, in the real world you'll will need doides to handle the 14A load.

Also... you may need to rt-click on the I-load and check the "This is an active load " option. With this option enabled the load will only supply a current if there is a voltage across it.

Regards, Ifixit
 
Last edited:

Ron H

Joined Apr 14, 2005
7,012
You don't have to select a diode model to make the sim run. I got it to run by adding a 1e12 resistor from the junction of the three sources to GND.
I don't know if this is relevant, but the SINE voltage needs to be specified as peak, not RMS.
 

pappano

Joined May 29, 2010
1
Hello Ifixit,

Thank you for your post. I was having the same problem, and your suggestion fixed it.

Thanks again.

Vincenzo Pappano
 

NSL22

Joined Dec 20, 2010
2
I created the same circuit with different source voltages and a resistor as the load and it's as if my voltage sources are half bridge rectified. Additionally, I don't understand why my peak looks like it is being over ridden by another waveform and why it's peak is so high. I specified an amplitude of 5V and its peak is 8.1V.

Please help if you can!

 

SgtWookie

Joined Jul 17, 2007
22,201
NSL22,
Take a look at the junction of the negative sides of V1, V2 and V3. You'll see that it looks like a triangle wave. If you right-click and mark that as a reference, you'll then be able to see the three sine wave phases 120° apart, and the DC out will look like a triangle wave.

The output frequency winds up being six times the input frequency, and the voltages of two of the phases are being added together.

Try grounding that junction and see what happens to the output waveforms.
 
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