DAVE FOC library

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Hi all,

Could you please help me to correlate my motor measurements with right FOC library arguments?
My motor measurements made with the RLC bridge:

1. Inductane. I made 3 measurements between U-V-W contatcs:
- 100 Hz -> 180 mH
- 1 kHz -> 172 mH
All three results are similar.

2. Resistance. I made 3 measurements between U-V-W contatcs:
- 100Hz -> 68 Ohm
- 1 kHz -> 102 Ohm
All three results are similar.

Other parameters provided by customer and measured:
- DC voltage: 320V
- Pole Pairs: 4
- Max speed: 4000
- Nominal current: 0.4 A
- Demagnetizing current: 0.4A
- B-EmfCoefficent: 35.8 Vrms/Kpm

I’m using Dave 4 with FOC library which is in beta stage. Do you recommend it ?
Should I switch back do Dave 3 ?

I can do experiments but would like to consult someone more experienced J

Thank you!

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Dear Karman Ghia,

Please use DAVE4 for your evaluation. Use an LCR meter at 1kHz to measure the phase-to-phase inductance of your PMSM motor and a multi-meter to measure phase-to-phase resistance. For other parameters, please use what have been provided to you.

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Dear Team,

Thanks for support !

My motor start tugging after switch to FOC control mode.
Could you please suggest what parameters should I adjust first ?

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Dear Karman Ghia,

I would recommend that you refer to the APP Help in PMSM_FOC APP. In the help section, please refer to the usage section. It give hints home to get started with the tuning of the motor.

As a start, we should always try to spin the motor with open loop V/F tuning. This give us an understanding of the motor performance in an open loop condition. After the motor is successfully turning. We can proceed to close loop tuning where you can select the control scheme, torque control or speed control. Please follow the instructions within the help document to get started.


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Hi,

I am performing my test using the XMC 750 Watt motor control kit.
I use the analog input (potentiometer) on the XMC1300 board to regulate the rotation speed.
The kit is configured in open loop control mode.

After a day of work, I’m able to run the motor controlled by FOC algorithm.

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Hi again,

I can hear a quiet knock at the moment the algorithm switch fron V/f to FOC mode. I use “V/f startup to FOC” mode with speed controll.
Is this “knock” expected or there should be something adjusted in the algorithm ?

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Hi Karman Ghia,

Good to know that you managed to spin the motor using FOC after a short time!


In the PMSM_FOC APP, you can select the startup control technique:
- Always in V/F open loop : Motor does not switch to closed loop and continues to run in open loop with the speed set value. FOC algorithm parameters have no effect in this mode.
- V/F startup with FOC : Control switches to closed loop at threshold speed value.
- V/F startup with MET to FOC : Control switches to closed loop with smooth transitioning MET algorithm.
- Direct FOC startup : Motor starts running in closed loop FOC without any open loop startup.

Did you select V/F startup with FOC in the APP? If so, the quiet knock observed could be the PI controller trying to compensate any difference in the system during the transition from V/F to FOC. You could try to tune the control parameters in the PI control loops to improve the performance. Also, can you try V/F startup with MET to FOC? This should yield a better performance too.
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