Timeline for Preventing spikes in inductor current (probably) caused by lab power supply
Current License: CC BY-SA 4.0
6 events
| when toggle format | what | by | license | comment | |
|---|---|---|---|---|---|
| Apr 28 at 17:46 | comment | added | jp314 | "esistor is a variable one" ==> it probably has significant inductance and magnetic pickup and is not really well suited for current sensing. Use a simple 'carbon' resistor. | |
| Apr 28 at 8:09 | comment | added | Tim Williams | It's a not-very-widely-known effect, but ringing can indeed occur within inductors. See for example, this waveform I obtained in a QR PFC converter: Ch.2 is the drain waveform (and thus applied inductor AC), Ch.4 is an inductive pickup near the winding. There is a series resonant mode, more or less where the winding (effectively short-circuited at both ends) becomes a 1/2 wave stub. | |
| Apr 28 at 0:47 | comment | added | Emerson SD | Right, that makes sense. Thanks for the suggestion! Just to clarify, if I short the resistor and still pick up a signal across it, that means that the spikes are actually just stray signals and not actually occurring in the current? Also, resistor is a variable one, that's just the value I have it set to for doing the testing. It'll eventually be taken out of the system. | |
| Apr 27 at 21:41 | comment | added | jp314 | It's not likely to be the inductor; unless it has a lot of parasitic capacitance, or some very severe eddy current effects (making it effectively ˆnotˆ even close to 610 uH). | |
| Apr 27 at 20:04 | comment | added | Tim Williams | An ideal inductance, yes. An inductor (real component), it's entirely possible. Also, shorting the load resistor in a converter under test, doesn't exactly sound like recommended operating conditions. | |
| Apr 27 at 19:15 | history | answered | jp314 | CC BY-SA 4.0 |
