What PWMSim can and cannot do
This page explains what PWMSim supports today. When a feature is not supported, PWMSim should say so instead of showing a result that looks correct but is not.
What it is for
PWMSim is designed for switch-mode power converters that use its supported set of SPICE features. You can:
- Run startup simulations. Simulate a circuit from startup to a chosen stop time and inspect the waveforms.
- Solve periodic steady state. For supported circuits with one switching period, solve the repeating behavior directly.
- Analyze waveforms. View voltage, current, and power; add calculations; use cursors, measurements, saved metrics, and FFT.
- Sweep parameters. Test a list of component values. Every point shows a result, error, or cancellation.
- Keep projects local. Save in the browser, share with a link, and export files you can keep.
- Import SPICE netlists. Convert supported netlists into editable schematics. The import report lists exact, changed, and unsupported parts.
What it is not
- It is not a general-purpose SPICE simulator. Some LTspice behavioral models and subcircuits are not supported. PWMSim reports them instead of guessing.
- It is not a device-physics simulator. Results use the documented models. They do not guarantee that a physical part or hardware test will match.
- It does not provide loop gain, Monte Carlo, or optimization analysis.
- Validation only covers the listed checks. A passing row on the validation page supports that measurement, not every possible use of the circuit.
Named capability gaps
| Gap | Status |
|---|---|
| Line-cycle PFC control | Not supported. |
| abc↔dq motor-drive interface | Experimental. It has no supported browser example or validation check. |
| Some LTspice behavioral models and subcircuits | Not supported. The import report shows what was changed or left out. |
| Loop gain, Monte Carlo, and optimization | Not supported. |
| Boundary flyback, active-clamp flyback, PSFB, LLC, and CLLC | Not supported where a required controller or validation check is missing. |
A claim deliberately not made
PWMSim does not claim that it can solve circuits that LTspice cannot. That claim would require real cases with exact versions, settings, logs, and repeatable tests.
If PWMSim gives a confirmed wrong answer for a supported feature, the correctness policy requires a public notice, a tested fix or a clear change to the supported limits, and a report explaining how future tests will catch the problem.