Engine stops after a few seconds.

[OttoBCN]

Hello everyone.
I am using the Motor Control WorkBench 6.3.0 application to generate the project. The inverter board is
B-G431B-ESC1. The motor is a 2-pole BLDC, 8.5V, it has a very low inductance of 0.04mH, an Rs of 0.37ohms and the B-Emf constant is 0.285 Vrms/kRPM.
In the data sheet
indicates that 60,000 RPM are the maximum it can reach.

I configure the application to reach 15000 rpm. After executing the acceleration ramp, the engine stops and gives start up failure.

Could you tell me what steps I should take to keep the motor turning. I would like to get a higher speed (25 or 30 KRPM) but first I'm trying to get it to run at 15KRPM.

Project attached.

Thank you all very much for your time.

[Gael A]

Hello OttoBCN,

Have you checked the MCSDK User Manual page dedicated to Firmware issues, their meaning and different steps to solve your issue ? You can find the User Manual via WorkBench, by clicking on About -> Documentations -> Documentation -> in the newly open browser window, click on User Manual. The one you are searching is called Firmware errors.

If this does not work, please reply by specifying each method you tried, and the exact behavior of the system (motor and Pilot UI) for each modifications made.

[OttoBCN]

Hello. Thanks for your help.

I'm sending you the screenshots of the first test I performed.

The engine accelerates for a few seconds and suddenly stops.
It does not maintain a constant speed, it only accelerates and stops.
The error reported is Speed ​​Feedback error.

In the Firmware errors section.
As a solution, the first solution indicates that the maximum value of the number of errors, the variance threshold and age speed depth vary. Could you recommend some values ​​to try?

Tell me if you need any more parameters or plot.

Thank you so much.

[OttoBCN]

Hello. Thanks for your help.

I'm sending you the screenshots of the first test I performed.

The engine accelerates for a few seconds and suddenly stops.
It does not maintain a constant speed, it only accelerates and stops.
The error reported is Speed ​​Feedback error.

In the Firmware errors section.
As a solution, the first solution indicates that the maximum value of the number of errors, the variance threshold and age speed depth vary. Could you recommend some values ​​to try?

Tell me if you need any more parameters or plot.

Thank you so much.

 

 

[OttoBCN]

I have been able to solve the problem by adding more inertia mass to the engine and now the engine stays on.

The maximum revolutions I have achieved are 25KRPM but they are not enough for my application. How could I adjust to 30 or 40KRPM? (My motor supports up to 60KRPM)

I have increased the PWM frequency to 30KHz but the speed has not increased. Should I go up to a higher frequency?

I have read that activating the Flux weakening regulator option can increase the engine RPM.
Should I do it?

Thank you.

[cedric H]

Hello,

What is your bus voltage ?

From one screen shot I saw 8 Volt, is that correct?

Regards

Cedric

[OttoBCN]

Yes. That is correct. the motor is this.

 

 

[cedric H]

Hello,

By definition, KV stands for “rpm per volt” applied to the motor.

Specifically, it is the no-load RPM speed divided by the voltage. In your case, a Kv rating of 2500 powered with 8 Volts will be limited to 20000 RPM.

I would suggest you to increase the VBus to reach higher speed.

Regards

Cedric

[OttoBCN]

In the motor datasheet, it indicates that it should not exceed 8.4V. Is there no other way to get more speed?

Thank you very much for your time.