I am currently using boost converter so I made all the calculation to make it work. My question is not about calculation it is about how physically is a boost converter working.
Here it is : the output voltage is depending on the duty cycle D. If we ignore the efficiency D=1-Vin/Vout then Vout = Vin/1-D. which means that when the duty cycle increase, the output votage increase.
The functionment of the converter is as follow:
- when the inside switch S is on there is a current charging the inductor
- when the inside switch S is off the inductor L oppose the variation of current and then a voltage in series with Vin is created so Vout > Vin
The only thing I don't understand is : why is the voltage increase with the duty cycle?
If the duty cycle increase ILmax will be higher but for an inductor U = L*di/dt. Then the voltage across the inductor depends on the decreasing of the current and not on ILmax. Since the load (C and R) is the same the decreasing of current should be the same and then VL should be the same no?
Then, physically why is VL depending on duty cycle?