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Simulation Configuration

This page describes the actual parameters exposed in Simulation Settings and backend runtime configuration.

Simulation Settings screen

Solver & Time

Core transient analysis parameters:

  • Integration method:
  • Auto (Backend default)
  • Trapezoidal
  • BDF1, BDF2, BDF3, BDF4, BDF5
  • Gear, TRBDF2, RosenbrockW, SDIRK2
  • Step mode: Fixed step or Variable step
  • Start time
  • Step size
  • Stop time
  • Max step
  • Relative tolerance
  • Absolute tolerance

Events & Output

  • Enable simulation event detection
  • Max step retries
  • Output points
  • Effective step (calculated automatically)
  • Duration presets: 1us to 100ms

Advanced Section

Transient Robustness

  • Max iterations (Newton iterations per step)
  • Enable voltage limiting
  • Max voltage step
  • Enable robust transient retries
  • Enable automatic regularization

DC Operating Point

  • Strategy:
  • Auto
  • Direct Newton
  • GMIN Stepping
  • Source Stepping
  • Pseudo-Transient
  • GMIN initial / GMIN final (when using GMIN Stepping)
  • Source steps (when using Source Stepping)

Formulation

  • Formulation mode:
  • Projected wrapper
  • Direct DAE formulation
  • Enable projected fallback when direct fails

Control block sampling (Ts)

Global control scheduling is no longer configured in Simulation Settings. Control scheduling is configured per control block in the Properties Panel:

  • Ts (sample_time) = 0: auto/continuous behavior.
  • Ts (sample_time) > 0: discrete update at that sampling period.
  • Mixed-rate control is supported by setting different Ts values on different blocks.
  • Scopes and probes do not expose Ts.

Thermal & Losses

  • Enable electrical loss tracking
  • Ambient temperature
  • Thermal network (global solver helper):
  • Foster
  • Cauer
  • Include conduction losses
  • Include switching losses

These options feed backend runtime (SimulationOptions) and post-processing telemetry (loss_summary, thermal_summary, component_electrothermal).

Component Thermal/Loss Parameters (Properties Panel)

For supported components (resistor, diode, mosfet, igbt, bjt_npn, bjt_pnp), Properties Panel exposes:

  • thermal single RC:
  • thermal_enabled
  • thermal_network=single_rc
  • thermal_rth, thermal_cth
  • thermal staged network:
  • thermal_network=foster|cauer
  • thermal_rth_stages, thermal_cth_stages (comma-separated)
  • shared sink coupling:
  • thermal_shared_sink_id
  • thermal_shared_sink_rth, thermal_shared_sink_cth
  • common thermal fields:
  • thermal_temp_init, thermal_temp_ref, thermal_alpha

Loss model options:

  • scalar switching energies:
  • switching_loss_model=scalar
  • switching_eon_j, switching_eoff_j, switching_err_j
  • datasheet surfaces:
  • switching_loss_model=datasheet
  • switching_loss_axes_current|voltage|temperature (comma-separated)
  • switching_loss_eon_table|eoff_table|err_table (row-major flatten)

The GUI pre-validates these contracts before backend execution and reports deterministic diagnostics (PULSIM_YAML_E_*) for invalid combinations.

Magnetic Core Parameters (Saturable Inductor)

Available when a Sat. Inductor component is selected. Requires pulsim ≥ v0.7.9 and magnetic_core_enabled = True.

Core control:

Parameter Type Description
magnetic_core_enabled bool Activates the nonlinear magnetic model.
magnetic_core_model dropdown saturation (smooth curve) or hysteresis (bounded state).
magnetic_core_loss_policy dropdown telemetry_only (virtual channel only) or loss_summary (also reports to loss/thermal tables).

Base saturation curve:

Parameter Default Description
saturation_current 10.0 A Current at which inductance begins to saturate.
saturation_inductance 1 µH Minimum inductance at deep saturation.
saturation_exponent 2.0 Sharpness of the saturation knee.

Core loss (Steinmetz-style):

Parameter Default Description
core_loss_k 0.0 Loss coefficient k (W/unit). Set 0 to disable.
core_loss_alpha 2.0 Flux-density exponent α.
core_loss_freq_coeff 0.0 Frequency-dependent loss coefficient.

Initial condition:

Parameter Default Description
i_equiv_init 0.0 A Initial equivalent magnetizing current.

Hysteresis model (magnetic_core_model = hysteresis only):

Parameter Default Description
hysteresis_band 0.0 Half-width of the hysteresis band (A).
hysteresis_strength 0.15 Coupling strength of the hysteresis state (0–1).
hysteresis_loss_coeff 0.2 Energy dissipated per cycle coefficient.
hysteresis_state_init 1.0 Initial hysteresis state (−1 or 1).

Virtual channels produced by the backend:

Channel key Unit Condition
<component>.core_loss W Always when magnetic_core_enabled.
<component>.h_state — Only when magnetic_core_model = hysteresis.
T(<component>.core) °C When simulation.thermal.enabled = true.

Symbol hint

The schematic symbol changes automatically: a solid bar indicates the saturation model; two dashed bars indicate hysteresis.

Backend Runtime (Preferences)

Backend Runtime screen

Path: Preferences → Simulation

  • Active backend
  • Version, Status, Location, Capabilities
  • Source: PyPI or Local
  • Target version
  • Local path
  • Auto-sync backend on startup
  • Install / Update Backend
  • Integration: Auto
  • Step mode: Fixed step
  • Relative tolerance: 1e-4
  • Absolute tolerance: 1e-6
  • Output points: 10000
  • Transient robustness: enabled
  • Backend target: v0.7.9