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--- simulating_a_time-varying_inductor_in_spice [2024/09/09 20:15] – bm
+++ simulating_a_time-varying_inductor_in_spice [2024/09/10 09:01] (current) – bm
@@ Line 34: / Line 34: @@
 The program asks you if you wish to automatically create a symbol. Click "yes". A .asy file is created which contains your custom time-varying inductor, typically in the folder 'C:Users\YourUserName\AppData\Local\LTspice\lib\sym\AutoGenerated'
-Let us test the time-varying inductor.
+To use the time-varying inductor in a circuit, click "component" (F2) and insert the custom inductor by searching "inductor" in the window.
-First, click "component" (F2) and insert the custom inductor by searching "inductor" in the window.
+Plotting the value of the inductance in SPICE in function of time is not straightforward. Let us just check some individual times: we compare the value of the current through and voltage over the inductor (i) in the case of the time-varying inductor at time $t_i$ (after the transition period), and (ii) in the case of a static inductor with value $L(t_i)$.
+Case (i): We apply a high frequency source in order to create an envelope facilitating comparison between both cases.
-Plotting the value of the inductance in SPICE is not straightforward. Let us just check some individual times: we compare the value of the current through and voltage over the inductor (i) in the case of the time-varying inductor at time $t_i$ (after the transition period), and (ii) in the case of a static inductor with value $L(t_i)$.
+{{:simulating_a_time-varying_inductor_in_spice-1.png|}}
+At a certain time, e.g., t=50µs, the value of the inductor equals $L$(50µs)= 5 mH + 3 mH.sin(2π.100 kHz.50 µs)=5 mH.
+If we then zoom in at the simulation at t=50µs, we find the peak value of voltage over and current through the inductor.
+Case (ii): We compare this value with a static inductor of 5 mH:
+{{:simulating_a_time-varying_inductor_in_spice-2.png|}}
+We find that both the current and voltage correspond to case (i).
+We do the same for a lot of other values of time, and always find a correspondence between both cases. This is not a rigid proof, but it gives us sufficient confidence that the inductor was modeled correctly in SPICE.
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