Unable to reach top speed

Kevin Lin

Other Parts Discussed in Thread: DRV8301, MOTORWARE

Hi,

I am trying to run a 24V-bldc motor with DRV8301 kit, but I can't get the motor to run at its rated top speed (5200rpm). When I try it with the GUI, it will show DRV fault when the speed reaches 4900rpm. Without the GUI, the fastest speed is approx. 2290rpm, even when SpeedRef_krpm is set to 5krpm. Does anyone know what is causing the issue? where should I look into?

Thanks,

regards,

Kevin

over 11 years ago

0 ChrisClearman over 11 years ago

TI__Guru** 119400 points

"without the GUI"

please confirm your compiler

http://e2e.ti.com/support/microcontrollers/c2000/f/902/t/295599.aspx

With the GUI

1. did you change your modulation to the full 2.0? <in MotorWare we changed the modulator and now use different terminology with the maximum being 1.333)

2. Sometimes your speed controller will slightly limit the max speed. Max sure USER_MAX_CURRENT is high enough...and you can always try in Torque mode which will always give you the highest speed.

0 Kevin Lin over 11 years ago in reply to ChrisClearman

Expert 1445 points

Hi Chris,

with Compiler 6.2.6, the motor can reach 4500rpm in Lab 4, but not yet 5200rpm.

Kevin

0 ChrisClearman over 11 years ago in reply to Kevin Lin

TI__Guru** 119400 points

Look at your modulation. Right now you are likely using 1.0

Use proj_lab10 to increase modulation to from 1.0 to 1.15 (space vector) or 1.333 (BLDC)

0 Kevin Lin over 11 years ago in reply to ChrisClearman

Expert 1445 points

Hi Chris,

I am using MotorWare 12, so I suppose the modulation is 2.0. However, the motor can reach 5200rpm if I have 2.0 for gMotorVars.OverModulation, so it seems my modulation is still 1.0. How do I replace my modulation with 2.0?

Thanks

Kevin

0 ChrisClearman over 11 years ago in reply to Kevin Lin

TI__Guru** 119400 points

Run proj_lab10 and set gMotorVars.OverModulation to (1.333)

You can search this forum, I've posted some write-up on this lab (it isn't included in the instaspin_labs.pdf)

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Unable to reach top speed