High power boost converter design

[dontexist]

I need to design 25-32V in 80V out 2.5kW, 31.25A boost converter. I cant find any controllers for this application. I need to simulate that in LTspice, what do you suggest for me? Im new this area thanks for help.

 

[Easy peasy]

It needs to be a current mode controller with slope comp, we have designed some nice discrete controllers to overcome noise in the current sense - feel free to PM for more info

 

[Easy peasy]

Also - your design calls for 100A in at 25VDC input, possibly better to have 3 units, each 34A in, phase displaced by 120 degrees, much easier to make and test and you reduce the current ripple requirement of the caps ...

 

[BradtheRad]

It makes sense to start out experimenting with low voltage low power converters. Then it should be easier to select a controller IC.

Consider simulating a buck converter since it's easier to achieve voltage or current regulation. On the other hand with a boost converter the target voltage 80V does not exist in the system (at first), and more effort is required to adjust for desired performance.

Work your way up to high power converters, probably toward 2 or more interleaved converters (as suggested in post #3).

 

[KlausST]

Hi,

100A average input. At 25V --> 80V means a duty cycle of 25V /(80V - 25V) = 0.4545
This also means a switch(ON) average current of 100A / 0.4545 = 220A
And a peak current of around 250A (depending on inductance)

Klaus

 

[dontexist]

Hi,

100A average input. At 25V --> 80V means a duty cycle of 25V /(80V - 25V) = 0.4545
This also means a switch(ON) average current of 100A / 0.4545 = 220A
And a peak current of around 250A (depending on inductance)

Klaus

I find duty cycle (80-25)/80=0.6875

 

[Easy peasy]

I'm not sure where Klaus gets his numbers, for a CCM booster with well designed choke and freq the peak current will only be 110A, for a single stage, for +/- 10A current ripple, not higher.

 

[KlausST]

I'm not sure where Klaus gets his numbers,

You are correct about the 110A. Thanks for pointing this out.

(I wrongly thougt about the input side to be switched 100A/0A, but it´s the output side that goes down to zero.)

Klaus

--- Updated Aug 14, 2021 ---

I find duty cycle (80-25)/80=0.6875

Again I was wrong. Thanks for pointing that out.

...not my day??

 

[dontexist]

How can i simulate this converter in LTspice with closed control loop?

 

[Easy peasy]

Read lots of app notes and try and learn from them, alternately enrol in a university for a Bachelor of Electrical & Electronic engineering.

There are other forums on other websites that have LT Spice specialists who could no doubt supply a circuit in 15 mins

Drawing a complete circuit with pen & paper is a good start.