Standstill

BLDC Six Step Startup Stall Debug

Symptom

At 4000 RPM commanded, the shaft rocks to a stop and FAULT latches overcurrent at 47 ms. The motor's registers are in the Circuit figure.

Measured run of the starter at 4000 RPM commanded: SPEED peaks at 875 RPM at 17 ms, swings to minus 268 RPM and dies to 0, while phase current climbs past the 45 A trip at 47 ms, where FAULT bit 0 latches, and rails at 50 A

Circuit

Block diagram: U1, an STM32F4, drives motor M1 at 0x50062000 over the bus, takes M1 interrupt lines 76 and 77, and prints on a serial console; below it, M1 registers with offset, access and units

Pass condition

The shaft holds the command and FAULT never sets. The graded bounds are in the figure.

Expected run at 4000 RPM commanded: SPEED rises to the command within about 100 ms and stays inside a 500 RPM band from 300 ms to 1 s; below, the four bounds graded on the run log's trace in each case

Notes

The commissioning tool writes the command in mRPM to 0x2000FF00. The rotor may start at any angle, and the drive runs 1000 ms.

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