Hi there - I decided that this weekend I would finally get myself to understand transformers. I'm interested in using them for the generation of high voltages (1kV+) from small voltages (5V).
My background is that I majored in EE and am currently employed in it. Still - I'm in over my head here with my problem.
I wanted to do a quick little demonstration of an isolated boost converter with a sense coil on the transformer. So I wired it up like shown here:
However - look at the part of the simulated waveform I zoomed in on. There is a high frequency (6MHz) sinusoidal signal on the VSense coil. Where is this coming from? You can see the switching speed on the primary coil is much slower than this.
Can anybody tell me where this is coming from? I'm guessing it's something strange related to the full bridge - but that's more me blaming the non-linear parts more than anything else :)
Thanks!
-Michael
PS I've copied and pasted the .asc file if anybody would like to try simulating my file.
Version 4 SHEET 1 880 680 WIRE 240 112 144 112 WIRE 416 112 384 112 WIRE 528 112 480 112 WIRE 608 112 528 112 WIRE 704 112 672 112 WIRE 736 112 704 112 WIRE 384 160 384 112 WIRE 384 160 368 160 WIRE 208 192 144 192 WIRE 240 192 208 192 WIRE 384 192 384 160 WIRE 416 192 384 192 WIRE 528 192 480 192 WIRE 608 192 528 192 WIRE 704 192 704 112 WIRE 704 192 672 192 WIRE 240 256 160 256 FLAG 208 192 0 FLAG 240 336 0 FLAG 736 176 0 FLAG 368 160 0 FLAG 160 256 Vout_sense FLAG 704 112 Vout SYMBOL current 144 192 R180 WINDOW 0 24 88 Left 0 WINDOW 3 24 0 Left 0 WINDOW 123 0 0 Left 0 WINDOW 39 0 0 Left 0 SYMATTR InstName I1 SYMATTR Value PULSE(1 2 0 1ns 1ns 1us 2us) SYMBOL ind2 224 96 R0 SYMATTR InstName L1 SYMATTR Value 1=B5H SYMATTR Type ind SYMATTR SpiceLine Rser=3D0.00000001 SYMBOL ind2 512 96 R0 SYMATTR InstName L2 SYMATTR Value 16=B5H SYMATTR Type ind SYMATTR SpiceLine Rser=3D0.00000001 SYMBOL ind2 224 240 R0 SYMATTR InstName L3 SYMATTR Value 1=B5H SYMATTR Type ind SYMBOL schottky 608 128 R270 WINDOW 0 32 32 VTop 0 WINDOW 3 0 32 VBottom 0 SYMATTR InstName D1 SYMATTR Value MBRS1100 SYMATTR Description Diode SYMATTR Type diode SYMBOL cap 720 112 R0 SYMATTR InstName C1 SYMATTR Value 1=B5F SYMBOL schottky 416 128 R270 WINDOW 0 32 32 VTop 0 WINDOW 3 0 32 VBottom 0 SYMATTR InstName D2 SYMATTR Value MBRS1100 SYMATTR Description Diode SYMATTR Type diode SYMBOL schottky 416 208 R270 WINDOW 0 32 32 VTop 0 WINDOW 3 0 32 VBottom 0 SYMATTR InstName D3 SYMATTR Value MBRS1100 SYMATTR Description Diode SYMATTR Type diode SYMBOL schottky 608 208 R270 WINDOW 0 32 32 VTop 0 WINDOW 3 0 32 VBottom 0 SYMATTR InstName D4 SYMATTR Value MBRS1100 SYMATTR Description Diode SYMATTR Type diode TEXT -266 212 Left 0 !.tran 10ms TEXT 256 16 Left 0 !K1 L1 L2 L3 1