On Tue, May 6, 2025 at 01:51 PM, <arhamishtiaq42@...> wrote:
yes I've changed my inductance to 110us, 250us, 1us but current is still high around 40A. and it is steady
Your messages are somewhat confusing.
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Of course the inductances should be in uH (micro Henrys), not us (micro seconds), but we get the idea.? I may not understand what you meant by "steady".? I'm assuming you did not mean DC, but maybe you mean the steady state RMS current after transients die out.
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Do we assume that we should start with the schematic named "Dabnew.asc" and change to these values:
- L1 = 110u
- L2 = 250u
- L3 = 1u
and that you see a primary (L1) current of 40 Amp, and you think that is too much?
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I do not see a current near 40 Amps.? My simulation shows that the primary current is 12.9 Amps RMS.
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Its waveform is rather peaky (distorted), and the peaks reach around +/- 28 Amps = 56 Amps peak-to-peak.
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What do you expect the primary (L1) current to be?
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The primary voltage is a +/-95 V square wave which comes out to 95.6 V RMS.? So the input VA product is 1233 Volt-Amps.? We know its volt-amps but not its power because the phase shift is not known.? If we look at the power source (V9), it supplies an average power of almost 600 watts to the circuit.? Therefore the power going into primary winding L1 must not be greater than 600 watts, even though its VA is 1233 Volt-Amps.
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The load resistor, R1, dissipates about 460 Watts.? 600 watts in, 460 watts out, so 140 watts is lost somewhere.??You can check for places where energy is lost.? For example, each of the four MOSFETs on the secondary side (M4, M5, M6, and M7) dissipates 32.4 watts, so you lose almost 130 watts in those four transistors.? I'm guessing the losses are a lot smaller in the transistors driving the primary.? But I leave that to you.
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In a real circuit, all inductors have resistance.? In LTspice, the default internal resistance of L1 and L2 is 0 ohms because they are coupled, and the internal resistance of L3 is 0.001 ohm.? It's unlikely that your transformer has that little DC resistance in it.
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Where else do you need help?
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Andy
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