Strange current waveform driving a BLDC motor using the IHM08M1 with the Nucleo F303

[der.ule]

I keep investigating why I have problems driving my motor with negative speeds.

I captured the phase voltage directly on the motor leads (yellow, cyan and magenta channels) and the current on the DAC output (Ia or Ib) and I noticed this peaks on the current waveform.

 

Zooming in, the currents themselves don't look bad at all

 

However I do not understand where does peaks are coming from

Any ideas will be greatly appreciated.

[der.ule]

Apparently those peaks in my current signal are somehow correlated to the switching of the hall sensors, instead of measuring the voltage in the motor phases, I measured the hall sensor signals and the output of the DAC (Ia or Ib current) and those peaks appear exactly when the H2 (on the J3 header of the IHM08M1) switches.

 

[GMA]

Hello,

Could you please give us your WorkBench version and if you are using "Additional Features"?

Best regards.

[der.ule]

Hi GMA,

I'm using the version 5.4.8 (this is going to be on the future a dual motor solution, as such I am unable at the moment to switch to v5.Y) with CubeMX 6.1.2 and HAL with Firmware STM32 FW V1.11.3

MCSDK_v5.4.8
WB_to_Mx version "1.5.1"
WB_to_Mx.template version "21-11-15"
 
[Device]
Firmware: ST MC SDK Ver. 5.4.8
 
[Modules]
MMICalc DLL - Version 1.0.4.0
 Basic Motor Control Serial Protocolo Library   - Version 3.3.0.0
TL_003 Frame Transport Layer - Version 1, 0, 0, 0
PL_001 Dynamic Link Library - Version 1, 1, 10, 0

As I mentioned in my other post, to start the development I am using a Nucleo F303 together with the IHM08M1 to drive a 24V Motor with 4 pole pair, rated speed of 3590 RPM and a calculated kv constant of 4,4V/kRPM.

[der.ule]

I created a new dummy project using a sensorless approach, but still with the hall sensors connected to the board, the strange waveform is still present

However, when I disconnected the hall sensors from the board, the waveform looks quite different:

Now I am a quite confused why this can be happening...

[GMA]

Hello,

Could you verify your HALL Sensor parameters setting please?

[der.ule]

Hi,

they are as shown (120 & 300) , I try varying the "placement electrical angle" from 300 down to 0, but I didn't see much change.

EDIT: My last statment is wrong, I did the tests changing the value directly on the "pmsm_motor_parameters.h", changing it on the Motor Control Workbench, did change the way my motor behave the waveform however, still looks similar.

[GMA]

And "Sensor displacement" is the correct one I assume...

[MK.1]

Hello, how do you measure the current? Are you using a DAC or current probe to your oscilloscope? If you are using a DAC, what pin of the board are you connecting from?

[der.ule]

Yes, I left it at 120 following the recommendations of the UM1052 and looking at the output of the hall sensors shown above.