Method for starting up at negative RPM

[Danu_Park]

I have been using the "STSPIN32G4-ACT" board and "ST Motor Pilot V1.2.9 - MC_FOC_SDK" to find the Rev-up parameters. However, negative RPM cannot be inputted into the Rev-up parameters. How can I start up at negative RPM?

Also, is there a way to operate the motor immediately without a Start-up phase?

Thank you!

[Gael A]

Hello Danu_Park,

The rev-up phase is made with absolute values of speed only, but this does not mean you can't start at negative speed, you just have to put a negative speed reference in the Pilot for the FW to apply your speed rev-up at negative speed.

Concerning your second question, if you wish to get rid of the Open Loop start-up, then you will have to switch either to a sensored solution (Hall or Encoder), or use our HSO algorithm which features a direct Closed Loop start-up.

[Danu_Park]

Thank you for your response. I have additional questions:
1. Can you confirm whether negative inputs are not allowed in the Rev-up parameters in "ST Motor Pilot V1.2.9"?

2. I want to start the motor in Open Loop and then switch to Closed Loop. Is there a way to do this? I use an encoder, but when it's set as the main sensor, the motor doesn't rotate, so I need to start in Open Loop and then switch to Closed Loop.

3. I generated code in MC Workbench and added a new timer interrupt in CubeMX. Then, after changing settings and regenerating the code in MC Workbench, the previously created timer settings in CubeMX disappeared. Is there a solution to this problem?

Thank you!

[Gael A]

Hello Danu_Park,

1 - Negative values are not allowed in the Rev-up parameters in ST Motor Pilot.

2 - What you describe here is the sensorless start-up method, this is not the case for Encoder as no Open Loop is needed. You can still enable the Open Loop feature using the Encoder in the Drive Settings tab, but this will not allow you to switch to close loop whenever you want. This is useful nonetheless to get data from the encoder and see if everything is correct.

3 - Unfortunately, generating a project via WorkBench overwrites any previous .ioc in the project folder. If you want to keep your modifications, the only way I see is to do a back-up of your .ioc file and then manually modify the new generated .ioc with your features.

[cedric H]

Hi,

In addition to point 3, if you start your project directly from an IOC generated by the MC Workbench, then your modifications will be kept, but you will not be able to modify your hardware configuration. The only modifications allowed have no consequences on the hardware IP initialized by cubeMX, so basically you will be limited to motor control algorithm configuration.

Hope it helps

Cedric