boost convetor.

Thread Starter

studenttwo34

Joined Jan 5, 2012
6
I am building a boost converter, for my final year project I require 300volts dc in 400 volts dc out. I have calculated my inductor to be 3mHENRY. And capacitor to be 1.25u farad . when i simulate this circuit. there is a surge to 480 volts . it then settles to around 410volts .My switch in the simulation is a Stw11nb80 mosfet (800volts 11amp). the current in the boost converter is 2 amps. Is this surge due to the mosfet? and what ways could this be maintained.also i have to do an interface for this boost with a pic does any one know anything about this . any help is welcome .Thanking you studenttwo34.
 

jimkeith

Joined Oct 26, 2011
540
Switching on the power to a series resonant circuit can cause the surge that you are viewing--this is also something that must be dealt with in real life--in some cases, pre-charge circuitry must be included limit the current during power-up.
 

Thread Starter

studenttwo34

Joined Jan 5, 2012
6
i believe i may have solved the surge problem by a snubber circuit still working on it. But the control circuit in the brief for my project it says build a boost convertor with input 300v DC and out put 400vDc for a danfoss inverter with a voltage and current control interface . any ideas where to start on control interface would be welcome.
 

crutschow

Joined Mar 14, 2008
34,281
i believe i may have solved the surge problem by a snubber circuit still working on it. But the control circuit in the brief for my project it says build a boost convertor with input 300v DC and out put 400vDc for a danfoss inverter with a voltage and current control interface . any ideas where to start on control interface would be welcome.
Post the circuit you have so far.
 

crutschow

Joined Mar 14, 2008
34,281
As jimkeith noted, you are seeing a resonant overshoot due to the resonant frequency between the inductor and the output capacitor (you see such an overshoot whenever you apply a step voltage to a resonant circuit). You need some way to slowly apply the voltage or limit the current.
 

Thread Starter

studenttwo34

Joined Jan 5, 2012
6
Thanks have put in a resistor seems to have sloved the problem . i need to use a microchip pickit 2 to control the on time of the mosfet.to keep the output voltage at 400 volts dc . i know i require some sort of circuit between the 400volts and pick as pick out is only 5volts . My question is what sort of circuit any ideas how this works? thanks for the help on the other part.

:D
 
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