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Test Report

Motor Self-Commissioning Accuracy Report

Aggregated accuracy evidence for the motor self-commissioning routine, comparing its resistance and inductance estimates against instrumented bench references.

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Document Information

Document IDOV-TEST-HW-SELF-COMMISSIONING
Test ID10
Version0.2
Date2026-09-10
Applies toopenvvvf-control-module, chassis-size-2
Product lineopenvvvf
Normative referencesOV-TEST-HW-MOTOR-RES-CAL, OV-TEST-HW-MOTOR-IND-CAL, OV-TEST-HW-RESISTOR-SANITY, OV-TEST-HW-INDUCTION-TESTBED, OV-TEST-HW-INDUCTION-RES-CAL, OV-TEST-HW-INDUCTION-IND-CAL, OV-SAF-HARA-CORE, OV-TEST-HW-INDEX
Index / Safety and Compliance / Testing and Validation / Hardware Tests / Motor Self-Commissioning Accuracy Report / Motor Self-Commissioning Accuracy Report
10 · v0.2 · 2026-09-10Download PDF
DoctypeTest Report
Product lineopenvvvf
Applies toopenvvvf-control-module, chassis-size-2
Version0.2
Date2026-09-10
DescriptionAggregated accuracy evidence for the motor self-commissioning routine, comparing its resistance and inductance estimates against instrumented bench references.
Test id10
Nav order357
Normative refsOV-TEST-HW-MOTOR-RES-CAL, OV-TEST-HW-MOTOR-IND-CAL, OV-TEST-HW-RESISTOR-SANITY, OV-TEST-HW-INDUCTION-TESTBED, OV-TEST-HW-INDUCTION-RES-CAL, OV-TEST-HW-INDUCTION-IND-CAL, OV-SAF-HARA-CORE, OV-TEST-HW-INDEX

Motor Self-Commissioning Accuracy Report

The motor self-commissioning routine (resistance and inductance estimation) currently produces calibration values with no formal accuracy evidence. This report aggregates the existing instrumented calibration-validation measurements so the self-commissioning results become traceable compliance artifacts. All values below are taken verbatim from the referenced calibration reports; no new measurements were made for this report.

Scope and referenced documents

Scope: the cal Motor.Resistance routine and the motor-inductance calibration routines (cal Motor.Induction.VHz for induction machines) as validated on the C2 chassis test fixture with two machine classes:

  • PMSM test motor on the Sierra CP Engineering fixture.
  • TECO Westinghouse MAX-IE3 7.5 kW induction motor (see Induction Motor Testbed).

Referenced validation reports:

Method under test

The self-commissioning routine estimates motor parameters from the inverter's own voltage and current measurements, without external instrumentation:

  • Resistance: cal Motor.Resistance drives a controlled current into each phase pair (UV, UW, VW), fits the voltage/current slope, and reports line-to-line resistance per pair. The per-phase value is half the line-to-line value.
  • Inductance (induction machines): cal Motor.Induction.VHz applies a 10 Hz V/Hz excitation, hunts for a modulation index producing roughly 5 A of phase current, sweeps modulation points around that operating point, and reports the series inductance Ls at each point.
  • Inductance (PMSM): the same comparison is planned for the PMSM test motor; the inverter-side run has not been performed yet.

The reference baseline is a BK Precision 894 LCR meter (20 Hz - 500 kHz), using DCR for resistance and Ls-Rs at 1.000 kHz for inductance, connected directly at the motor phase leads with the inverter disconnected.

Acceptance criteria

The source calibration reports do not state formal pass/fail tolerances. The following criteria are provisional and proposed for formal adoption:

Parameter Provisional tolerance (estimated vs. instrument reference) Basis
Resistance (motor windings) within ±10 % Largest observed deviation: -6.5 % (PMSM, 120 V run) and +7.3 % (induction, ~80 V bus)
Inductance within ±10 % Largest observed deviation: +2.4 % (induction)
High-impedance sanity load within ±10 % Observed: -10.2 % vs the LCR reference on a 23 Ω power resistor at low current (marginally outside tolerance; treated as an exception, see Results)

These tolerances are marked provisional pending review; they are consistent with the systematic offsets (IGBT knee voltage, dead time, current-sensor scaling) analyzed in the source reports.

Results

PMSM test motor

Parameter Instrument baseline Self-commissioning estimate Deviation Source report
Resistance, line-to-line (run at ~50 V bus) 15.293 mΩ (DCR) 15.4704 mΩ (average of UV/UW/VW) +1.2 % OV-TEST-HW-MOTOR-RES-CAL
Resistance, line-to-line (run at ~120 V bus) 15.293 mΩ (DCR) 14.3067 mΩ (average of UV/UW/VW) -6.5 % OV-TEST-HW-MOTOR-RES-CAL
Resistance, per-phase (run at ~50 V bus) 7.6465 mΩ 7.7352 mΩ +1.2 % OV-TEST-HW-MOTOR-RES-CAL
Resistance, per-phase (run at ~120 V bus) 7.6465 mΩ 7.1534 mΩ -6.5 % OV-TEST-HW-MOTOR-RES-CAL
Inductance (Ls at 1 kHz) 71.2980 µH / 34.6583 µH (two Ls-Rs readings) TBD - inverter inductance calibration run pending TBD OV-TEST-HW-MOTOR-IND-CAL

Known-load sanity check (23 Ω power resistor)

Parameter Instrument baseline Self-commissioning estimate Deviation Source report
Resistance, UV line-to-line 23.3070 Ω (DCR) 20.94 Ω -10.2 % (marginal - just outside the provisional ±10 % band; accepted as exception) OV-TEST-HW-RESISTOR-SANITY

The 10.2 % low reading is explained in the source report: at ~0.3 A the IGBTs operate in the knee region and the linear fit absorbs most of the knee as an offset, biasing the slope low. This deviation sits just outside the provisional ±10 % band, so the test point is recorded as a marginal exception rather than a clean pass, with the knee-region bias documented as the basis for the exception. This test point confirms the routine produces the right decade on a non-motor load; it is not motor-grade accuracy.

Induction motor (TECO MAX-IE3 7.5 kW)

Parameter Instrument baseline Self-commissioning estimate Deviation Source report
Resistance, line-to-line (~80.6 V bus, ~40 A max) 415.730 mΩ (DCR) 446.16 mΩ (average of UV/UW/VW) +7.3 % OV-TEST-HW-INDUCTION-RES-CAL
Resistance, per-phase ~207.9 mΩ 223.08 mΩ +7.3 % OV-TEST-HW-INDUCTION-RES-CAL
Inductance, Ls (highest-current sweep points, 40/80/120 V bus) 17.8565 mH (Ls-Rs, 1 kHz) ~18.3 mH +2.4 % OV-TEST-HW-INDUCTION-IND-CAL

Conclusion

Against the provisional ±10 % criteria:

  • PMSM resistance: pass at both bus voltages (+1.2 % / -6.5 %).
  • PMSM inductance: open - measurement pending (TBD).
  • Induction resistance: pass (+7.3 %).
  • Induction inductance: pass (+2.4 %).
  • Sanity load: marginal - 10.2 % low against the LCR baseline, just outside the provisional ±10 % band; accepted as an exception because the low-current IGBT knee-region bias documented in the source report explains the deviation.

The self-commissioning routine produces resistance and inductance estimates within a few percent of the instrumented baseline on real motor windings at representative operating points. The remaining open item is the PMSM inverter-side inductance run.

Traceability

  • This report satisfies the compliance need for accuracy evidence of the motor self-commissioning routine: calibration values consumed by the control firmware are now backed by instrumented comparisons rather than unverified self-estimates.
  • The aggregated evidence traces to the platform hazard analysis (OV-SAF-HARA-CORE), where correct motor-parameter estimation underpins the torque-control assumptions of the VVVF control strategy.
  • Each row in the results tables traces to a formal test report (test IDs 1-6) that retains the raw command logs, telemetry (JSONL), and instrument photographs as primary artifacts. Add a row here whenever a new motor class or harness is validated.

Artifacts

All primary artifacts (command logs, telemetry logs, plots, instrument photos) are retained in the referenced source reports; this report intentionally duplicates none of them.