FAQ

FAQ

Must a simulation file use the .pes extension?

No. A simulation file is YAML text, and the parser does not require a particular extension. .pes is the project convention and makes the file's purpose clear.

Which bridge model is used by default?

When neither the file nor the command line selects another model, each unit uses pwm_averaging. This retains sampled control and PWM-register timing while omitting carrier ripple. See Converter and Bridge Models.

What do the three bridge flags select?

They are complete run presets:

• --switching selects switching bridges and fixed-step RK4;
• --pwm-averaging selects PWM-period-averaged bridges and fixed-step RK4;
• --averaging selects ideal averaged bridges with continuous control and adaptive DP45.

A repeatable --set override has higher priority than the preset. The preset has higher priority than the simulation file, which has higher priority than defaults.

Can one system mix bridge models?

Yes. Set units.<name>.bridge.model independently for each unit. The three command presets change all units unless an explicit --set units.<name>.bridge.model=... override takes priority.

Does ideal averaging preserve PWM and computation delay?

No. Ideal averaging uses a controlled voltage-source bridge and continuous controller states. ADC windows, controller interrupts, computation completion, carrier comparison and PWM shadow/active registers belong to the sampled switching and pwm_averaging models. Sampled-only settings may remain in a shared configuration and are silently ignored by ideal averaging.

How should solver accuracy be checked?

For fixed-step runs, reduce simulation.solver.dt. For adaptive runs, reduce rtol and atol, and constrain max_step if the dynamics require it. A result is numerically credible when the conclusion no longer changes materially under further refinement. The CSV output interval is not the integration step. See Solvers.

Can state initial values be specified?

Yes. Use simulation.initial.states for explicit state values, or continue from a saved states.csv with --initial. The initial time is exact and is not rounded onto a controller or PWM grid. See Events and Restart.

Can a run continue from an intermediate output row?

Yes. Supply the saved states.csv with --initial and select the row using --initial-time. PESLite restores the saved physical and discrete continuation state needed by the selected model. The accompanying simulation.pes records the resolved configuration used for the original run.

Why is a watched name prefixed by the unit name?

The entity prefix distinguishes the same quantity on different devices. For example, vsc_1.vdc_pu and vsc_2.vdc_pu are different values. Run --list-states to inspect state names, and use --progress together with --watch because watched values are printed on progress lines.

Does output remain in memory until the run ends?

No. Enabled histories are streamed to CSV in batches controlled by simulation.solver.write_length. simulation.output.record_every or period controls which snapshots are retained. Access through the Python Result object loads a requested output file when that result is read. See Output and Results.

Why are some output files absent?

states.csv, summary.json and simulation.pes form the basic result. Signal and energy files appear only when their corresponding output options are enabled. Fields that have no result use None in the Python API or null in JSON rather than a fabricated numeric value.

Are parameter changes validated during a run?

Yes. set events validate their dotted paths and values at the event boundary. Derived defaults are resolved again when affected parameters change. Event targets and component names must be unambiguous within the assembled system.

Can custom components and controllers be used from a simulation file?

Yes. Modules in peslite.addons.control and peslite.addons.components are discovered into the same registries as built-in types. Types elsewhere may use the public registration functions for control loops, circuit elements, events and solvers. The YAML entry then uses the registered type name and goes through normal parameter validation. See Extending PESLite.

Is the exported C++ simulator a wrapper around Python?

No. It is a standalone C++17 source file with no third-party C++ runtime dependency. Only parameters selected during export are mutable afterward; the generated executable reports them with --list-params. Unsupported configuration values supplied through --config are warned about and ignored. See C++ Export.