Hello, I'm trying to simulate an AC/DC converter for a class project. Now, this was an assigned circuit there isn't much I can do about the design. There's on component that I can't quite figure out.



as far as I researched I understand that it is a sort of bidirectional thyristor but don't quote me on that. The book I'm referencing is in Portuguese so that's helpful, also there's no name attached to it. It would be helpful if I knew what that box is exactly so that I can simulate it in psim.

The full circuit I need to simulate is this:


And if it helps here are some examples of what the graph for the currents and voltages across different components should look like. In advance I am terribly sorry for the quality, there's not much I can do about that either.



Thanks for any support !!

 

You will have a (dangerous) blow if you use that circuit.
That setup cannot use Silicon Controlled Rectifiers as shown. They cannot be turned off, they will simply short the input power supply.

They have to be necessarily MosFet's / BJT';s / IGBT's so that they can be turned off by removing the drive.

That is a classic Quasi Sine Wave bridge invertor with a 25% dead time and T2 and T4 may be Darlington Transistors (T1 and T3 too may be similar) making the whole setup using Darlington NPN transistors.

That 3 terminal white box may be simply another NPN transistor (?).

Can we have the full schematic?

 

You will have a (dangerous) blow if you use that circuit.
That setup cannot use Silicon Controlled Rectifiers as shown. They cannot be turned off, they will simply short the input power supply.

They have to be necessarily MosFet's / BJT';s / IGBT's so that they can be turned off by removing the drive.

That is a classic Quasi Sine Wave bridge invertor with a 25% dead time and T2 and T4 may be Darlington Transistors (T1 and T3 too may be similar) making the whole setup using Darlington NPN transistors.

That 3 terminal white box may be simply another NPN transistor (?).

Can we have the full schematic?

Thanks for the help, I Think I can use this information somehow on the presentation. Unfortunately, This is the whole schematic, this the whole information about this circuit available on the book. Although, I did forget to mention that for my purposes the teacher said to omit the DC battery and assume a resistive load.

Here are some details I've been able to gather from more research and my teacher (doesn't want to give every detail, understandable):

- Teacher was able to give was that this is supposed to be a boost rectifier circuit.
- The middle source is a AC current source.
- T1 and T3 are definitely thyristors in parallel with diodes
- T2 and T4 according to the book in Portuguese they are "tiritores duais", from what I can gather, they might a pair of either transistors or thyristors in a bidirectional configuration. Or DIACs or TRIACs I still have to test those on the simulation

 

You are using the term Thyristor too freely. The collection of SCR's, Triac's, Diac's .. all come under the family of Thyristors.

They cannot be turned off, they will simply short the input power supply.

I was too hasty in that comment. A closer study indicates that this can work. The sequence is critical. We have to ensure that T1 and T3 are never ON simultaneously at any time, the same for T2 and T4.
T2 and T4 can be turned off, they are transistors.
It is a Quasi Sine Wave invertor.

 

You are using the term Thyristor too freely. The collection of SCR's, Triac's, Diac's .. all come under the family of Thyristors.

I was too hasty in that comment. A closer study indicates that this can work. The sequence is critical. We have to ensure that T1 and T3 are never ON simultaneously at any time, the same for T2 and T4.
T2 and T4 can be turned off, they are transistors.
It is a Quasi Sine Wave invertor.

I have few observations on why wouldn't it be an inverter

- Like I said the teacher explicitly stated the we omit the DC source and assume a resistive load.
- The source of this circuit is an AC source not DC
- The output current I2 , as seen by the graphs I uploaded is not AC it's DC, it's a rectifier circuit. I1 is the input
- The output graph of a Quasi Sine Wave invertor doesn't look anything like the other graphs

 

I have few observations on why wouldn't it be an inverter

- Like I said the teacher explicitly stated the we omit the DC source and assume a resistive load.
- The source of this circuit is an AC source not DC
- The output current I2 , as seen by the graphs I uploaded is not AC it's DC, it's a rectifier circuit. I1 is the input
- The output graph of a Quasi Sine Wave invertor doesn't look anything like the other graphs

That does not make any sense at all.

 

I have few observations on why wouldn't it be an inverter

- Like I said the teacher explicitly stated the we omit the DC source and assume a resistive load.
- The source of this circuit is an AC source not DC
- The output current I2 , as seen by the graphs I uploaded is not AC it's DC, it's a rectifier circuit. I1 is the input
- The output graph of a Quasi Sine Wave invertor doesn't look anything like the other graphs

If V1 is an AC source, then the 4 diodes D1...D4 form a bridge rectifier to charge V2, a battery or a load. The thyristors play no role than to serve as a means of destroying the Source when they are triggered.

If V2 is an AC source, then all the 4 diodes, D1...D4 form a dead short on the half cycle !!!

It cannot be anything other than a Quasi Sine Wave Invertor.

 

If V1 is an AC source, then the 4 diodes D1...D4 form a bridge rectifier to charge V2, a battery or a load. The thyristors play no role than to serve as a means of destroying the Source when they are triggered.

If V2 is an AC source, then all the 4 diodes, D1...D4 form a dead short on the half cycle !!!

It cannot be anything other than a Quasi Sine Wave Invertor.

look sorry for this post man, I already gave up I tried simulating what you said and the output is not what the same of the reference from the book, tbh I don't think the teacher was mindful of the circuits for the project. She said it was a boost rectifier, upon closer inspection I saw that the boost rectifier in the book looks nothing like the this circuit. Honestly I don't care anymore. Thanks for for the help