LAUNCHXL-F2800137: Lab 3: Motor stops spinning at particular frequency

Rahul Khedkar

Part Number: LAUNCHXL-F2800137
Other Parts Discussed in Thread: BOOSTXL-DRV8323RH, MCT8316A

Hello TI experts,

I'm testing a low inductance motor on LAUNCHXL-F2800137 and BOOSTXL-DRV8323RH. I'm now working out LAB 3 from universal motor control lab i.e. closed loop operation.

Motor stops spinning at 450Hz commanded frequency. No motor fault is observed, PWMs are still driven (fine audible noise is present). I have attached debug screenshot and user_mtr1.h file.

After motor stops spinning, I give speed reference command as 0Hz, controller slowly spins down the motor (deduced from audible noise, the motor makes till it stops).

One thing I observe is that there is a different audible noise at frequency command of 440Hz which seems different than acoustic noise produced by motor.

With the same motor, I have tested FOC on F28069M and trapezoidal commutation on MCT8316A across full working range. So this audible noise observed is different than trapezoidal commutation noise.

Could you please help solve this issue?

Thanks.

user_mtr1.h

over 1 year ago

0 Jiaxin Teng over 1 year ago

TI__Expert 4660 points

Hi Rahul,

What is the modulation method and modulation index? In level 3, only the current control loop is closed. I suspect there is not enough voltage output to drive the motor at 450Hz.

Thanks,

Jiaxin

0 Rahul Khedkar over 1 year ago in reply to Jiaxin Teng

Prodigy 70 points

Hello Jiaxin,

I'm not exactly sure with modulation method and index. But I see that motorVars_M1.svmMode is set to SVM_COM_C in expressions window.

And USER_M1_MAX_VS_MAG_PU is set to 0.66 which is by default. I haven't made any changes to this configuration.

I observe that max PWM duty cycle at 440 HZ is about 18%, so I believe that we have enough margin in terms of output voltage, please correct me if I'm wrong.

Thanks.

0 Jiaxin Teng over 1 year ago in reply to Rahul Khedkar

TI__Expert 4660 points

Hi Rahul,

Can you try to run level 4 (fully closed-loop) to the desired speed?

Thanks,

Jiaxin

0 Rahul Khedkar over 1 year ago in reply to Jiaxin Teng

Prodigy 70 points

Hello Jiaxin,

I have been able to run level 4. There are some issues, I'll share with you in a few days.

Regards,

Rahul.

0 Jiaxin Teng over 1 year ago in reply to Rahul Khedkar

TI__Expert 4660 points

Hi Rahul,

Sounds good.

Thanks,

Jiaxin

0 Rahul Khedkar over 1 year ago in reply to Jiaxin Teng

Prodigy 70 points

Hello Jiaxin,

I'll ask a new question since my query on Lab4 might take some time to solve.

Thanks for your support.

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LAUNCHXL-F2800137: Lab 3: Motor stops spinning at particular frequency