Hey Power Electronics expert ,
I want to learn close loop simulation in ltspice for flyback converter. I am doing research on it...but some how no success so far.
I need your support guys..!
I want to start with Voltage Mode Control. Thanks in advance !

 

i see no feedback... how is your closed loop supposed to work?

 

i see no feedback... how is your closed loop supposed to work?

yes, there is no control loop. Need support to implement close loop. thanks !

 

To make everything work from zero is hard. Here is something similar to what you are doing.
I do not use the power line power source because that adds complications. Here I use a 420V DC Vin to simplify things.
This putouts 24V.
It does not regulate off the output like you are doing but off of L3 winding which is close to what L2 is doing.
FB is the input of the error amp.
TC is the output of the error amp.
Gate will show you the duty cycle.

This might be too hard to understand. I can find a simple version later. Maybe someone will post a 3843 (1242) simple supply that you can look at and is closer to what you want.

 

If you have not much experience with switching regulators, I strongly recommend the good old appnote 19 (june 1986!) from Linear Technology (now Analog Devices). https://www.analog.com/media/en/technical-documentation/application-notes/an19fc.pdf

It was written for the LT1070-family of switching regulator ICs, but there are so much basics that it can easily be transferred to many other switching regulators. In my opinion it is like a Bible for switching regulator design. There are discussed many different topologies and also the feedback for flyback converters.

 

What you need to know is here:
https://e2e.ti.com/cfs-file/__key/communityserver-discussions-components-files/196/0412.slup340.pdf

 

Thanks for your reply !
I am trying to implement the comp

To make everything work from zero is hard. Here is something similar to what you are doing.
I do not use the power line power source because that adds complications. Here I use a 420V DC Vin to simplify things.
This putouts 24V.
It does not regulate off the output like you are doing but off of L3 winding which is close to what L2 is doing.
FB is the input of the error amp.
TC is the output of the error amp.
Gate will show you the duty cycle.

This might be too hard to understand. I can find a simple version later. Maybe someone will post a 3843 (1242) simple supply that you can look at and is closer to what you want.
View attachment 356674

ens

What you need to know is here:
https://e2e.ti.com/cfs-file/__key/communityserver-discussions-components-files/196/0412.slup340.pdf

Thanks all you reply!
My intention is to implement this into LTSpice.