Designing Modular Multilevel Converter

Thread Starter

Ajeeth93

Joined Jul 6, 2021
8
Hi!

I am designing Modular Multi Level Inverter in LTSpice using MOSFETs using Near Level Control PWM technique.

I have attached the LTSpice file in this thread.

I do not understand why my model does not give me the desired output voltage value.

Could you please have a look at it?
 

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Papabravo

Joined Feb 24, 2006
17,300
The simulation runs but all the voltages ate negative with respect to node 0 in the simulation.
What is the desired output voltage?
Where do you expect that voltage to be?
 

Thread Starter

Ajeeth93

Joined Jul 6, 2021
8
What is the desired output voltage?
Where do you expect that voltage to be?
Hi!
I gave a Sinusoidal reference value V(Sine) of 90 V to a 100 V dc supply inverter. It tries to follow the reference. However the magnitude of output voltage V(n019) is very small. I would like to get an output value equal to the Reference value.
Sin_page-0001.jpg
 

Papabravo

Joined Feb 24, 2006
17,300
Yes I got the same result. Why are all your voltages negative. You would expect some positive voltages but as you go up the tree they get flatter, but never positive. Why is that?
 
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Thread Starter

Ajeeth93

Joined Jul 6, 2021
8
Yes I got the same result. Why are all your voltages negative. You would expect some positive voltages but at you go up the tree they get flatter, but never positive. Why is that?
I think it is because most of the supply voltage is dropped across Sub-Module-1. That is exactly my problem. Ideally the Voltage must be distributed even across all the Sub-Modules.
 

Papabravo

Joined Feb 24, 2006
17,300
I think it is because most of the supply voltage is dropped across Sub-Module-1. That is exactly my problem. Ideally the Voltage must be distributed even across all the Sub-Modules.
I think there might be a flaw in that approach, but I can't see a way to make that arrangement work.
 
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