BLDC Sensorless FOC (TLE9879 Kit) - Not able to acheive higher speed

Announcements

Webinar: Integrated solutions for smaller, simpler low-voltage motor control design.
Join the webinar to experience!

Tip / Sign in to post questions, reply, level up, and achieve exciting badges. Know more

cross mob
User18368
Level 1
Level 1
Hello,

I am using BLDC sensor-less FOC for motor control, I wanted to achieve 4000 rpm at 11V, But the motor I am using is getting saturated to 2300 rpm, when I increase the voltage speed is able to increase.
But, the requirements are to achieve higher RPMs with 11Volts. is there any software based restrictions to the stated problem. I have tried changing multiple parameters to fetch results but nothing seems to work out.

I suspected if there is limitation on Hardware but the Hardware vendors were able to run the motor for 6000rpm at 11Volts. So I feel the software restriction is existing. Can you suggest if any parameters is
to be changed to run the motor at higher rpm.

I have tried few parameters like Speed Limit, Reference Current. And I have modified other parameters with respect to motor parameters? Is there any limitations on Demo Code?

Regards,
Harsha
0 Likes
9 Replies
Fiz
Moderator
Moderator
Moderator
First like received 50 replies posted 25 replies posted
Hello Harsha,

Since your are able to achieve higher speed when applying ah higher voltage, it seems like your motor is the limiting factor.
Which motor are you using?
How are your hardware vendors driving the motor?
There is a speed limitation to the SW, but it is at 32768 rpm, since we a int16 data is used to store the speed data.

Best,
Fiz
0 Likes
User18368
Level 1
Level 1
Fiz wrote:
Hello Harsha,

Since your are able to achieve higher speed when applying ah higher voltage, it seems like your motor is the limiting factor.
Which motor are you using?
How are your hardware vendors driving the motor?
There is a speed limitation to the SW, but it is at 32768 rpm, since we a int16 data is used to store the speed data.

Best,
Fiz


Hello Fiz,

Thank you for your response, Motor which I am using is having a rated capacity of 400-500W, 5 pole pair, Maximum current rating of 40A.

Our Hardware vendors are driving the motor with a test bench as far as I know(Without any software intelligence) and they have a plot which states the capacity of motor. (Further information is out of my reach).

As you suggested I have tried increasing the speed limit as well as current limit before, and there wasn't much significant change to speed of motor!

Regards,
Harsha
0 Likes
Fiz
Moderator
Moderator
Moderator
First like received 50 replies posted 25 replies posted
Hi Harsha,

you could try to increase the number of pole pairs in the FOC SW.
This should also increase your motorspeed.

Is your motor running in closed or open loop?

Best,
Fiz
0 Likes
User19000
Level 1
Level 1
Hi Harsha,
I have meet the same problem like you. Do the problem solved now and how?

Best,
Hongwen
0 Likes
User19528
Level 2
Level 2
First like received
Hello,
I have meet the same problem like you. Do the problem solved now and how?

My BLDC have a max operating speed of 10000 rpm.
I wanted to achieve 9000 rpm whatever the power supply voltage (10 V, 13V or 16V)
My issue is that the motor speed is getting saturated to 4000 rpm at 13V. When i increase the voltage (16V) i'm able to reach 6000 rpm
Did you found solution please ?

Regards,
0 Likes
User19528
Level 2
Level 2
First like received
Hello,
I have meet the same problem like you. Do the problem solved now and how?

My BLDC have a max operating speed of 10000 rpm.
I wanted to achieve 9000 rpm whatever the power supply voltage (10 V, 13V or 16V)
My issue is that the motor speed is getting saturated to 4000 rpm at 13V. When i increase the voltage (16V) i'm able to reach 6000 rpm
Did you found solution please ?

Regards,
0 Likes
User10891
Level 1
Level 1
Hi All.

I have meet the same problem but I found something and solve it.

in this Code has three PI function.

1.Speed PI (Emo_Ctrl.RefCurr) ,emo.c
2.Q PI (Emo_Foc.RotVolt.Imag), emo_ram.c
3.D PI (Emo_Foc.RotVolt.Real) , emo_ram.c

each function has min/max value for out , IOut and it is calculate at initial routine

and.. each out put value limitation these min/max value.

so, if you can see the each output/IOut/min/max value via debugger then

you can check these output value are limit by min/max value.

I hope this is help for you

Thanks.
0 Likes
User19528
Level 2
Level 2
First like received
Hi,

Thank you for your feedback
0 Likes
User20268
Level 1
Level 1
First like received
Hello Fiz,

Is there some solution on why the max speed is limited in sensorless FOC? Any guidance will be greatly appreciated.

Regards,
John
0 Likes