Motor does not start

[Jorgie]

Tools:

• MCSDK - 6.2.1
• MC Workbench 6.2.1
• STM32CubeMX - 6.10
• STM32CubeIDE - 1.14.1
• ST Motor Pilot - 1.2.5

Hardware Setup

• Nucleo-0G474RE
• STEVAL-IPM30B (My own version of the board, same circuit and layout)
• X-NUCLEO-IHM09M2
• I-PMSM motor 9 Pole Pairs, 220W, 36V

DETAIL

Unable to start the motor.

First attempt to start the motor always results in an Over Current Fault.

All three of the low side PWM signals go high at the same time

Second attempt - Motor Pilot Status - Goes from WAIT_FOR_MOTOR then START.

I only seem to be getting a PWM signal on PWM-A-H, current is drawn for about 5 seconds.

EXPECTED BEHAVIOUR 

I would expect PWM to be generated for each phase 120 out of phase with each other.

Then I would expect the motor to start turning.

[Gael A]

Hello Jorgie,

I will try to replicate your setup in our lab to see if I experience the same issue, in the meantime I have a few suggestions:

Is your motor profiled already ? Have you managed to make your motor run using this configuration on Profiler ?
Also, have you tried to make it run in Open Loop mode ? At first in voltage to see if PWM are generated correctly, you can look into the User Manual if needed.
What is happening after the second attempt ? Does the Pilot return any error ?

Then, I have more general questions, maybe your current ramp is simply too big, have you tried reducing your current target in your rev-up to see if the Overcurrent fault still occurs ? Have you looked at your phases currents, do they really reach the Overcurrent threshold ?
If you have only one phase drawing current, have you made sure the wires were connected correctly ? Also, are you in three shunts or single shunt configuration ? Any sensors ?

[Jorgie]

Hi Gaël,

Many thanks for the prompt and helpful reply.

I have not been able to perform a profile of the motor. The Motor Profiler starts but never seems to end.

I have not been able to find "Open Loop" in the manual I assume you mean UM3027..

I believe that the wave forms going to the Gates is shown in this image, does this wave form look normal? The voltages are 2V at the peak but only about 10ns apart:

The phase currents are shown in this image:

All three phases are taking current.

No sensors

3 current sensors

I am thinking that I will need to change to a more suitable motor. The one I have is a bike motor that has 9 pole pairs and a max RPM of 285.

[Gael A]

Hello Jorgie,

The Profiler's behavior is startling me, is the motor spinning but the Profiling never stops or is the motor staying put and the profiling bar stays at 0% ? Have you tried tinkering with the max speed and max current values to see if any improvement occurs ?
When I talk about the User Manual, I mean the one you can find via WorkBench, clicking on About -> Documentations -> Documentation. Then in the newly opened browser tab you should find Open loop description and usage.

Have you tried reducing the rev-up current before starting ?

[Jorgie]

Hi Gaël,

The motor never starts as I immediately get an Over Current error and "Firmware fault detected." 

I have now tried Open loop but I need to spend some time understanding it.

[Gael A]

Hello Jorgie,

This may sound dumb but have you checked on the UM2709 that your Hardware configuration matches your SW configuration ? Especially single / three shunts and internal / external opamps.

[Jorgie]

Hi,

I have, however I'm still getting the same issue. I have ordered the ST development board to ensure it's not my own board causing the problem and I'll also try it with a 2 or 3 pole pair motor. 

I'll let you know how that goes once I get the board and motor.

Regards

Sean