Problem to Reach Rated Speed

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Problem to Reach Rated Speed

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PedroCastro
Contributor III

Hello everbody,

I am using the KMS v1.2 with a FRDM-KV31 for a current control project. After the KMS v1.2 was released I started to use the sensorless control with hall startup and indeed the startup torque control is much better. However, it does not reach the rated speed of 1050 rom and its maximum is around 480 rpm. I have tested another project without the hall startup and it does reach the rated speed with the same current requested.
What is a possible workaroud for this issue?

Thanks in advance

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linestream-adam
Senior Contributor I

Pedro,

I found the bug.  Updated file attached.

View solution in original post

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linestream-adam
Senior Contributor I

Pedro,

There was a bug in the SNLESSHALL reference projects when using torque mode.  I've corrected it.  Try this updated drv.c file to see if it resolves the issue.

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PedroCastro
Contributor III

Hi, It is in fact in your reply! I didn't see it when you replied.

I have tried the drv.c and it reaches the nominal speed, but control doesn't look like a startup hall, it is much lower than the other one. Any hint why that happens?

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linestream-adam
Senior Contributor I

Pedro,

No worries.  In the version that I posted, it now does the startup similar to sensorless velocity.  In that it will track the speed reference until it reaches the crossover speed ("Speed Threshold" in GUI), once the speed reference reaches the crossover speed it will transition into FOC and will run in torque mode as you expect.  If you want to speed up faster before getting into FOC, you can increase the acceleration and jerk of the speed profile before the transition into FOC.

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PedroCastro
Contributor III

I got a bit confused. Is it a modified SNSRLESS control or I KMS GUI should I keep using the SNSRLSSHALL project and then copy your drv.c in the generated code?

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linestream-adam
Senior Contributor I

The drv.c file I provided is for the SNLESSHALL reference project.  There were some defects in that file for running the SNLESSHALL project in torque control mode.

In the SNLESSHALL project, the goal is to start the motor using the Hall sensors but then transition into FOC.  It isn't intended to use the Halls for the complete speed range.

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PedroCastro
Contributor III

Hi Adam,

one thing I would like to point it out is that using this drv.c I am not able to do the parameters setting in KMS. It cannot even measure resistance and inductance. In fact in torque control it reaches rated speed.

Could you send me an updated file?

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linestream-adam
Senior Contributor I

Pedro,

I found the bug.  Updated file attached.

View solution in original post

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linestream-adam
Senior Contributor I

Thanks for letting me know Pedro.  I'll look at the issue and get it resolved.

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PedroCastro
Contributor III

Hi Adam,

thanks for your response, but I think you have not attached any files!!

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philip_drake
NXP Employee
NXP Employee

I see the attachment Pedro that AdamReynolds‌ attached.

Regards,

Philip

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linestream-adam
Senior Contributor I

There isn't a file on my reply?

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linestream-adam
Senior Contributor I

Pedro,

Interesting.  Can you attach your system.h file to this forum post?  This will help me understand this issue further.

Thanks

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