EV-INVERTERGEN3 Minimum DC Bus Voltage Requirement for Low-Voltage Testing

[ragulsenthil]

Hello,

I am currently working with the EV-INVERTERGEN3  reference design and trying to validate a PMSM motor.

For initial testing and safety reasons, I am supplying only 29V DC to the inverter instead of a high-voltage battery.

However, the system immediately enters FAULT state and does not allow PWM to run. From MCAT, I do not see overcurrent or overvoltage faults, but the inverter does not transition to RUN state.

My questions:

1. Is it possible to operate EV-INVERTERGEN3 with a low DC bus voltage (e.g., 29V) for motor validation?

2. Are there minimum DC bus thresholds hardcoded in firmware?

3. Does the precharge or HV safety logic prevent operation below a certain voltage?

4. Is firmware modification required to allow low-voltage testing?

My goal is only low-speed motor validation before moving to high-voltage testing.

Any guidance would be appreciated.

Thank you.

[JozefKozon]

Hello Ragul,

unfortunately this will not work. Please check: https://www.nxp.com/docs/en/user-manual/UM12210.pdf

And this link.

Q1 — Minimum DC‑bus voltage?
[A] No published value. The inverter is designed for 400–800 V, and no low‑voltage mode is documented.

Q2 — Can it operate at 24–48 V?
[A] No. At ~29 V it enters FAULT and cannot reach RUN.

Q3 — Are modifications required (UVLO, pre‑charge, DC‑bus UVP)?
[A] NXP does not provides any official support or method to modify these safety mechanisms.

Q4 — Current sensing recalibration?
[A] Would be required, but irrelevant because low‑voltage traction operation is unsupported.

With Best Regards,

Jozef