# High current ripple through inductor

I am trying to figure out a way to create a high current ripple through and inductor, similar to that of the ripple the inductor sees in a SMPS. I would like to put a 2A peak to peak 400KHz current through a 10uH inductor. It is alright if it is a sinusoidal waveform rather than the saw tooth the inductor sees in a SMPS.

Ideas I have tried:

-Find a high enough power AC supply that operates at 400kHZ. I have not been able to find a supply with a high enough power rating that can generate 400kHz.

-Use a transformer with a very high turns ratio to step down the voltage/step up the current from a low current signal generator. The issue is that at 400kHz, a 10uH part has a relatively high impedance and I would need a very high input voltage to obtain 2A across that high of a load impedance.

-Use a H-bridge to drive current through the inductor in each direction. The issue here is I need a DC current through the part as well, and I can not vary the inductance or frequency so I am unable to vary the ripple at all.

-Design a buck converter for the DC and ripple current I want. This works, but I need to test many parts at the same time so I would need many buck converter circuits.

• H-bridge sounds plausible. It is essentially a synchronous buck-boost converter with input and output shorted together. Continuous mode with DC current should not be a problem. Sep 15, 2015 at 22:48
• Testing multiple parts at the same time will require separate drives for each part to maintain good precision, whether it's a buck or H-bridge or anything. Sep 16, 2015 at 2:33
• @venny I have played around with an H-bridge in simulation. It seems like the only way to vary the ripple current is by changing the switching frequency or the inductance. How do I set both the DC and ripple current if I have to stick with 400kHz and 10uH?
– BDP
Sep 16, 2015 at 13:19
• When current, frequency and inductance are constant, the only variable that remains is voltage. It could be done by a buck converter before the H-bridge, which would be adjusted by sensed current ripple. Sep 16, 2015 at 13:34
• @Venny I believe that changing the input voltage will vary both the DC and ripple current, but if I can't change my frequency or inductance and need a certain percentage of iripple compared to Idc, how do I vary the ripple and dc separately to get that ripple to dc ratio? As far as I can tell my only two parameters I can vary are input voltage and duty cycle, is that enough? Thank you!
– BDP
Sep 18, 2015 at 22:01