Calculation of the ripple rate r of the second inductor of the SEPIC circuit

小太阳yy

Calculation of the ripple rate r of the second inductor of the SEPIC circuit [Copy link]

Is it correct to use the following formula to calculate the inductance value for this type of SEPIC using coupled inductors?

For other DCDC power topologies, the ripple rate of the inductor is r=VIN*D / IL*L*fsw. How do you calculate the r of the sepic secondary inductor? The current IL of the secondary inductor is IL=IOUT, and the L value is the same as the primary inductor. What about the duty cycle and VIN? I am a little confused. They must be different.

maychang

『Calculation of the ripple rate r of the second inductor of the SEPIC circuit』

The parameters of the components of the switching power supply are usually more than the number required for calculation. Then some of the parameters should be selected by ourselves, and then the values of other parameters should be calculated. The current ripple rate of the inductor is the ratio of the current change value to the average value, which is often selected. After the selection, other values can be calculated. Of course, other parameters can also be selected first, and the ripple rate can be calculated from other parameters.

小太阳yy

maychang posted on 2022-10-4 12:09 "Calculation of the ripple rate r of the second inductor of the SEPIC circuit" The parameters of each component of the switching power supply are usually more than the number required by the calculation. So among them...

I understand what you mean. I mean that when I started calculating, I chose a value of about 0.4. Then, after I actually chose the inductance value I wanted, I wanted to work backwards and calculate r from the inductance value to see if it was much different from the value I had chosen before.