Transformer_capacitor

104

01:28:26

WTF??? Simulate and see the strange behavior of the secondary voltage. Neither the frequency matches the primary. Is the simulation correct? In EasyEDA this does not happen

published 2 years ago

JoDaGi

2 years ago

That looks impressive! I changed the value of the capacitor to 100nF and after a while resonance seemed to be achieved. Putting a 1 Ohm current sensing resistor into each lower arm allowed me to observe the phase relationship, THANKS!😁

592azy2circuitdude

2 years ago

I think the simulation is working fine. You have stumbled upon 2 interesting effects that can explain everything: Resonance and leakage inductance.

592azy2circuitdude

2 years ago

The resonance is formed by the transformer driving a capacitive load. This forms a resonate tank circuit at 178Hz. That's the low frequency component of the secondary waveform.

592azy2circuitdude

2 years ago

Look closely at the secondary, and you should see some higher frequency ripple on it of 1KHz. This is the primary voltage transferred to the secondary. It is attenuated (reduced) so much because most of it is dropped in the leakage inductance of the transformer. How's that? 😉

Rubenfb

2 years ago

But the same circuit in LTSpice and EasyEDA has a normal behavior!!!

592azy2circuitdude

2 years ago

Great question! I hope I have a good answer. Probably, the transformer model in LTSpice and EasyEDA is ideal, meaning that only the turns ratio is used, and other effects are not. However, in EC, the model is more complex (and realistic). Try this: Change the coupling coefficient of the transformer to 1. It should now work as you expected!

Rubenfb

2 years ago

Exactly!! The coupling coeficient is the answer. If you change to 1, the weird effect disappears. Thanks all ;-)

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