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Hi,

Im trying to run an induction motor with the following evaluation boards: EVAL-M1-101T and EVAL-M1-IM818-A.

Motor charateristics:

P = 0.75kW

I = 2 A

U = 400 V

RPM =1390

poles = 4

Rs = 19.4 ohm

Lq = Ld = 70 mH

Ke = 3.173 V / Krpm, this value caused an error, the lowest i could put was 40

Researching in the forum i found out that i need to make some ajustments based on this document:Induction motor control by iMOTION™ (infineon.com)

I tried to follow that, but i don't think my MCEWizard config is correct.

The motor started, but stoped 1s after and gave gatekill error. To errase that error i tried to change the Gatekill Input Source to Gatekill-Pin, and the motor didn't gave an error, but the currents i saw in MCEDesigner were very high, so i think the problem is in the MCEWizard config.

It is possible for someone to check this and help me put this motor running correctly?

Best Regards

Paulo

Solved! Go to Solution.

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Hi @PauloM,

Please contact the motor manufacturer for the maximum permissible speed of the motor as we can see 1668 RPM as max RPM for 60Hz.

Please calculate BaseHz from the maximum speed as mentioned in the above post.

Please contact motor manufacturer for determining the maximum current at which motor can be safely operated. As EVAL-M1-IM818 allows maximum current of 20A. Please increase the gatekill comparator current limit to higher values( Values less than 20A) to avoid gatekill error and safely operate inverter board/motor.

Please let us know if any further details are required.

Thanks,

Krupashankar

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Ke=3.173V？This is bad.

Would you please double check them.

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Hi, i double checked the value and it was a bit diferent, i probably used the wrong pole pair number.

I used this formula:

Ke = (Vpp/fmeasured)*number of pole pairs * 3.4

Ke = (7.5 / 26.18) * 2 * 3.4 = 1.948

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Hi Paulom：

Would you like double check your test?

From your picture, on delta connecting and 50Hz, it is 230V-1.39rpm

Ke is about 165V/rpm

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For Y connect, the Ke is about:

Ke=400V/1.39krpm=287V/krpm

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For Rs , you need DC for test.

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i remake the Rs measurement with a multimeter and it was 10.45 ohm.

For the Ke measurement i followed this guide iMOTION™ MADK - How to Measure Motor Parameters (infineon.com). Do i have to do other way to induction motors?

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Multimeter? It is not good for Rs test as error.

Please use DC souse and input DC current to winding by 10~20% rated current, test winding voltage and to gain Rs by Ohm's Law.

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I made that now, i used 0.2A and the voltage i got was 4.2V, so the R = U/I = 21 ohm

Divide that by 2 to get Rs for each phase and the result is 10.5 ohm, right?

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There are right！ Great！

10 ohm is limited of better resistance measure.

Booking Ld/Lq(100Hz) Rs, and working open loop, change delay time and for the phase current go to better sin waveform. And try again.

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Hi,

Thank you for you answer.

I now have in MCEWizard the values for Ld/Lq (100Hz), and Rs. For the Ke i put the value you gave me. I think i have all setup for Open loop.

But can you clarify where i can change the delay, and what you mean by "go to better sin waveform".

Thank you

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This "delay current sampling time" is debugging. As on turn "ON" and "OFF" time, switching noise will be on the waveform. So you need delay some time to "sampling" for remove there noise and gat better waveform.

If current waveform is clear, your design is better and can go next. If not, maybe some risk in next job.

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Thank you for the aswer,

I tried to run the motor, and it worked, the problem its that when the refence speed is above 500 i get gatekill error.

I measured Iu in rpm lower at 300 rpm.

Then i increased reference speed to 500 rpm and i got gatekill fault.

What do you think that could cause this?

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Would you like share Itrip RC LPF and test waveform?

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Yes i will try, can i do that test in MCEDesigner, or i need to connect Itrip pin in power board to an osciloscope?

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I tried to run the motor again without Comparator selected in gatekill input source, and the motor runs well up to max rpm with normal current, the problem is that when load is applied to the motor the current goes up without any control, so i need the comparator to give the overcurrent error and stop the motor, how i can properly configure it to this motor?

I think that the bad configuration was the reason the gatekill error.

The MCEWizard config is in the .zip file, if you could check it out.

Thanks

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Hi @PauloM,

Only open-loop control is possible in the iMOTION controller for the Induction motor.

As the closed-loop control is not possible the current is not controlled and it can reach higher values.

In the case Induction motor control number of motor poles and maximum RPM are the two essential parameters, so the error for the Back-EMF constant can be ignored.

Please let us know if any further details are required.

Thanks,

Krupashankar

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Hi @Krupashankar,

I think i was using the open-loop control, in the script there is one variable "AngleSelect" and it is given the value 0 to select Open-loop control, im also using voltage control as said in the document. Do i need to setup more variables to select Open-loop control?

Also, i double checked the motor values and i have some questions.

The phase resistance is 10.45 ohm.

The indutance at 100 hz was 68.85, and at 1khz was 52.55, which one i use?

In terms of the script i don't think i made the correct calculations to the BaseHz, how it would be made based on my values?

Best Regards,

Paulo

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Hi @PauloM,

Yes, the open-loop control method is enabled.

In the case of open-loop control of Induction motor, the number of motor poles and maximum RPM are the two essential parameters as mentioned earlier.

Basehz is the base speed at which the motor needs to be operated where the maximum speed is represented as 16383(3000 RPM). If the base speed is 1500 RPM the BaseHz = 8191.

BaseHz = (Base speed / Max Speed) * 16383

Based on the maximum speed and base speed for the Induction motor operation please modify BaseHz.

Try reducing TrqBoost in the script in order to reduce overcurrent.

Please let us know if any further details are required.

Thanks,

Krupashankar

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Hi @Krupashankar,

Thank you for you answer.

I am not sure the maximum velocity of the motor is 3000 rpm since i don't have the datasheet, i only know the rated speed is 1390, by the motor plate. Its better to just use the 1390 rpm as maximum speed or to use the 3000 rpm?

I modified the maximum speed, and changed torque boost from 490 to 49, then testing, i still got gatekill error when the rpm are above 500, in both of the maximum speeds defined.

Seing the wave of Iu, when is in A and when is A(rms).The value isn't scaled correctly, is it?

Is better to monitor current using Id and Iq?

If you have some more sugestions how to properly setup the current comparator, i would apreciate it.

In the .zip file i send the updated version of the MCEWizard config.

Best Regards,

Paulo

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Hi @PauloM,

Please contact the motor manufacturer for the maximum permissible speed of the motor as we can see 1668 RPM as max RPM for 60Hz.

Please calculate BaseHz from the maximum speed as mentioned in the above post.

Please contact motor manufacturer for determining the maximum current at which motor can be safely operated. As EVAL-M1-IM818 allows maximum current of 20A. Please increase the gatekill comparator current limit to higher values( Values less than 20A) to avoid gatekill error and safely operate inverter board/motor.

Please let us know if any further details are required.

Thanks,

Krupashankar

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Hi @Krupashankar,

Since im not able to contact the motor manufactor, we are using max speed 2000 RPM, and maximum current of 10A, we will probably change that values, later in development, but for now, the motor is working well. So thank you and @喜马拉雅之雪 for all the help.

I will start another thread if i need to solve new problems.

Best Regards,

Paulo