Physics, asked by Vikkyvikas1189, 1 year ago

How to deciede value of inductor and capacitor in boost dc dc converter?

Answers

Answered by vaishu01
0
When designing a boost converter to take a low input voltage to a high output voltage, there are many knowns that you control, such as the choice of inductor and the duty cycle of the switching that is at the heart of the boosting voltage. The below circuit is a demonstration of what I'm talking about - no values since its not a question about specifics.



If you're running the boost converter in discontinuous mode, with a known duty cycle and period (D and T respectively), input voltage (Vi) and inductance (L), you can calculate various important values such as peak current through the inductor. But the sticking point that I keep arriving at is how exactly do you calculate the output voltage over a theoretical load, R? Or, as I'm being led to believe, does the output voltage/current actively depend on the value of the load R?

Much of the literature I read assumes that you know Vo and Io already (which when you're designing this, it does make sense to know what your desired output is), but I'm approaching this as if I don't, yet not getting anywhere, since the equation regarding the voltage gain:

VoVi=ViD2T2LIo+1

includes both output voltage and output current, which seem to depend on each other from other equations:

Io=Imax⋅δT2

which if you sub in the equation for δT and Imaxjust results in the first equation. I can't find a way of isolating one variable. Trying to equate the energy across the capacitor similarly isn't leading me in the right direction.

What I don't understand is that for the given four variables at the top of my post, I'm left with the output voltage and current as free variables, which leads me to posit that these then must depend on the load? Is my thinking correct, or do I misunderstand the concept of what is going on? I know I'm going about this the 'wrong' way, it's just a curious thought experiment as I'm trying to make sense of other circuits, where the PWM/duty cycle switching and other components are already set.

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