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by namibj 139 days ago
Do you have any opinions on the use of frequency-domain/harmonics-based SPICE for high-frequency (relative to the transition frequency of the power and their pre-amp devices involved) fixed-frequency converters, particularly the resonant kinds?

At some point the gate signals become digital pre-distortion for the pre-amps ("gate drivers") and come out of a wave table like synthesizer, and sure, system-level behavior still matters...
1 comments
eschu 136 days ago
I am not sure that I know what harmonics-based SPICE is. Is it about AC analysis?
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namibj 128 days ago
A related mode is "11.3.12 .PSS: Periodic Steady State Analysis" in [1], though that's arguably "light mode"; the heavy mode is "HB (Harmonic Balance Analysis) Calculates steady states of nonlinear circuits in the frequency domain. General Form .HB <fundamental frequencies>" as implemented in Xyce[0]:

Harmonic balance (HB) is a technique that solves for the steady state solution of nonlinear circuits in the frequency domain. In harmonic balance simulation, voltages and currents in a nonlinear circuit are represented by truncated Fourier series. HB directly computes the frequency spectrum of voltages and currents at the steady state solution. This can be more efficient than transient analysis in applications where a transient analysis may take a long time to reach the steady state solution. In particular, HB is well suited for simulating analog RF and microwave circuits.

HB supports an unlimited number of independent input tones for driven circuits in both serial and parallel builds of Xyce. The output of HB analysis is the real and imaginary components of voltages and currents in the frequency domain. Xyce also provides time domain responses of a circuit. By default, the numbers of samples in both time and frequency domain outputs are the same. However, the number of time domain samples can be much larger than the number of frequency domain samples by setting numtpts in .options hbint. This enables the users to use a small number of harmonics for each tone and produce well-resolved results in time domain.

[0]: https://xyce.sandia.gov/documentation-tutorials/ [1]: https://ngspice.sourceforge.io/docs/ngspice-html-manual/manu...

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