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BOOSTXL-DRV8304H: Instaspin FOC motor braking

Part Number: BOOSTXL-DRV8304H
Other Parts Discussed in Thread: LAUNCHXL-F28027F, , TMS320F28027F, MOTORWARE
  • I'm working on a custom motor board. It consists of TMS320F28027F + DRV8304H. The schematic is very close to LAUNCHXL-F28027F+BOOSTXL-DRV8304H. The controlled motor is 180kV 19W BLDC (still I use FOC, like for PMSM). I had an issue with blown 1.75A (2 seconds) fuse in DC bus. Nominal current for the motor is 200 mA on 12V. I had isolated JTAG (for programming/debug) and USB-to-COM (for interacting with the PC)  connected to the board. The board was powered from external 12V source.

The controlled object is a platform moving by position sinusoidal pattern 0.5Hz in a horizontal plane +-3 deg  (eg speed reference is also sinusoidal), gear ratio is 120:1, so the motor spins by the pattern 0.5Hz +-190RPM. It made a few cycles and then the fuse blown up. I logged an estimate of DC current (just abs(ia)+abs(ib) + abs(ic) measured by ADC) - 160mA continuous. It may be accidentally, or wrong wiring. Later I could not reproduce this case. Still, I'm investigating the possible reasons.  

The question: could it happen because of absense of braking circuit? What happens if to use INSTASPIN-FOC as is without dynamic/regenerative braking? Where does the braking energy go? Does it matter for 19W motor? If it does, I need a smooth sinusoidal profile so I can not use simple dynamic braking, shorting the windings by the low side MOSFETS for a long time. The motor generates when the speed sinusoidal pattern slows down and eventually changes direction. There must be something automatic, not affecting the control performance.
Also, 12V and 3.3V have common GND, just like in the kit. Is it safe? Plus when the fuse blown up I had  USB-to-COM GND also connected to the board. I don't mention JTAG GND because it was isolated.