Electronic – Ideal DC Transformer in LTSpice

dc-transformerltspice

I am conducting some simulation work where I would like to incorporate the LTC3588-1 component model in LTSpice.

I have an electrical model of a physical system that requires the use of an ideal DC transformer. While I have used the model successfully in Simulink and SIMetrix, such a transformer is not available in LTSpice.

Could anyone please offer some advice about how an ideal DC transformer may be constructed in LTSpice?

For reference, documentation for the component I am trying to simulate is available for
SIMetrix and
Simulink

Best Answer

You probably mean a small-signal DC transformer, for use in .AC analysis. If so, the basic configuration is a current source at the input, dependent on the output current, and the output voltage source dependent on the input voltage:

dc1

Both obey the external parameter, D=Ton/T. This is fixed, however, so to make D variable, you need to replace it with a voltage:

dc2

If the waveforms will have sharp transitions & co, you may need to add a Cpar=<...> to the input source. Or, if the output voltage proves to be too "stiff", replace it with a current source, like this (note the changed sign in Bin):

dc3

This also adds the possibility of an output resistance, which makes the circuit behave more like it should in a real world. Be sure to not exaggerate with the values, for example try not to set Rout=1n, because that would mean there would be a division by 1n, or 1G, side by side with 1n, which would make a dynamic range of 1e18 -- this is an almost guaranteed method to bring out timestep too small errors. In general, 1000x less than what you'd expect should do anywhere. Add a grain of salt and you're done.

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