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Motor Control ICs Forum Discussions

JasonLEE
Level 4
Level 4
First like received First solution authored 50 replies posted

Hello,

I'm having a hard time controlling RPM.

I set the RPM to 2000 RPM when I set it.
However, there is a symptom that the RPM does not exceed 1000 and continues to go down.

I've modified several parameters for this symptom, but it never improved.

If you are aware of this problem, please reply.

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48 Replies
喜马拉雅之雪
Employee

Hi:

Would you share that what time your motor can't run to high speed and your design? The output is open load or...?

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JasonLEE
Level 4
Level 4
First like received First solution authored 50 replies posted

Hi,

What kind of design should I share?

It uses EVAL-IM818LCC and EVAL-IM828XCC development boards.

 

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喜马拉雅之雪
Employee

What kind of load of IM818 and 828 board?

Did you have and share there motor drive current waveform by MCEWizard?

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JasonLEE
Level 4
Level 4
First like received First solution authored 50 replies posted

How should I measure the motor load?
I've got an impeller.

Is there a waveform in MCEWizard?
If I have a waveform, which waveform should I share?

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As there waveform are from soft "read", you can dubg your setup(MCEWizard) with system.

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喜马拉雅之雪
Employee

Hi:

Would you share the project detailed information?

From your comments, we get out you testng IM818 and IM828 board. But there are  power boards and they can do most function. we don't know that about what's your project and you want.

For waveform, you can gat out MCEDesigner:

_0-1672104410144.png_1-1672104503299.png

 

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JasonLEE
Level 4
Level 4
First like received First solution authored 50 replies posted

Hi,

 

IM828XCC Single Shunt's no-load waveform.

I set it to 250 RPM.

1.png

2.png

3.png

   

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JasonLEE
Level 4
Level 4
First like received First solution authored 50 replies posted

IM828XCC Leg Shunt's no-load waveform.

I set it to 250 RPM.

 

11.png

22.png

33.png

   

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JasonLEE
Level 4
Level 4
First like received First solution authored 50 replies posted

Our system is for FAN motor for HVAC.
The waveform you just measured was tested with a customized board.

Backemf and all parameter values were accurately measured.

I attached the .mc2 file, so please check it.

 

 

 

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喜马拉雅之雪
Employee

What's kind of your board?

EVAL-M1-IM828-A is single shunt solution.

EVAL-M1-IM818-A is leg shunt solution.

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JasonLEE
Level 4
Level 4
First like received First solution authored 50 replies posted

Hi, @喜马拉雅之雪 

1. I have both EVAL boards.

EVAL-M1-IM828-A is single shunt solution.

EVAL-M1-IM818-A is leg shunt solution.

2. We also have two customized boards with the same design.

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喜马拉雅之雪
Employee

For IM818-A board, as motor poles setup  is 20, so the drive target is 333Hz.

Would you try different setup with No.58/60/94 question?

My forvert is:

   Fiux estimator time constant: 3~7msec,

  Gatekill filter time constant:1uS.

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JasonLEE
Level 4
Level 4
First like received First solution authored 50 replies posted

Hi, @喜马拉雅之雪 

My motor pole is 10P.

20P is set incorrectly.

Can you provide a solution based on 10P?

Q58) What value should I set for this part?

I need a maximum of 2500 RPM.

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喜马拉雅之雪
Employee

Happy new year

1) Would you please best setup there question.

2) 3~7mS can meet 10P application.

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JasonLEE
Level 4
Level 4
First like received First solution authored 50 replies posted

Hi @喜马拉雅之雪 

In case of Q58, I didn't know how, so I left it there
The rest were set up as you provided the solution, but the problem did not improve.

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喜马拉雅之雪
Employee

1) What's your power input? AC380V or ...

2) Could you test the motor KV value?

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JasonLEE
Level 4
Level 4
First like received First solution authored 50 replies posted

1) AC 3 Phase 380V.

2) Could you tell me how to measure the motor KV value?

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Have you a digital oscilloscope?

If OK, OSC probe connect to motor pin: U-V.

Rotating the motor at a constant speed, test U-V pin voltage waveform by OSC. Intercept the waveform and upload.

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JasonLEE
Level 4
Level 4
First like received First solution authored 50 replies posted

Hi.

Two methods were measured using an oscilloscope.

1) U, V phase is measured in detail with an oscilloscope.
RPM is 200.
This is rotated by the motor driver.

2) U phase was measured in Oscilloscope.
This part rotates consistently by hand.

1.jpg

2.png

  

  

 

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喜马拉雅之雪
Employee

Could you zoon in the waveform for read the voltage and frequency?

_0-1672193670231.png

 

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喜马拉雅之雪
Employee

The motor is Y connect? The waveform is U to three-phase midpoin?

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JasonLEE
Level 4
Level 4
First like received First solution authored 50 replies posted

The motor connection is a Y connection.

The waveform is a U-V connection.

Put a scope on the U
I have connected a GND to V.

 

scope.jpg

scope2.jpg

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喜马拉雅之雪
Employee

Would you please double check the DC BUS voltage? From your waveform, it is DC290V.

_0-1672197035153.png

 

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JasonLEE
Level 4
Level 4
First like received First solution authored 50 replies posted

안녕,

다시 측정했습니다.
확인해주십시오.

 

scope3.jpg

 

scope4.jpg

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Would you please check your test system. The waveform is different of standard.

This is typical of the switching waveform of EVAL-M1-IM818/828-A @AC380V 3-phase input:

_1-1672201769669.png

 

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喜马拉雅之雪
Employee

? DC270V?

_0-1672201356227.png

 

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JasonLEE
Level 4
Level 4
First like received First solution authored 50 replies posted

This is DC 600V.

Not 270~300.

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JasonLEE
Level 4
Level 4
First like received First solution authored 50 replies posted

Could you tell me where and how you checked the waveform? I will check the same way.

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喜马拉雅之雪
Employee

If BUS is DC600V, the waveform is not right.

Could you made the testing picture/photo (include probe and OSC )?

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喜马拉雅之雪
Employee

Thanks for your testing and waveform. The motor is Ke=132.7V/krpm.

The motor Vp-p@2000rpk=265V*2*1.414=375V

DC BUS: Vbus=Vp-p/((T-2td)/T)=399V

So if DC BUS is high than DC400V, the motor can go to 2000rpm.

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JasonLEE
Level 4
Level 4
First like received First solution authored 50 replies posted

테스트한 보드는 EVAL 보드가 아닌 맞춤형 보드입니다.
그러나 디자인은 EVAL 보드와 같습니다.

범위는 U, V, W 섹션에서 측정되었습니다.
잘못된 사항이 있으면 알려주세요.   

KakaoTalk_20221228_140105517.jpg

KakaoTalk_20221228_140105517_01.jpg

SCOPE5.png

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JasonLEE
Level 4
Level 4
First like received First solution authored 50 replies posted

The motor is Ke=132.7V/krpm.

The motor Vp-p@2000rpk=265V*2*1.414=375V

DC BUS: Vbus=Vp-p/((T-2td)/T)=399V

So if DC BUS is high than DC400V, the motor can go to 2000rpm.

 

I don't know if this value is correct.
The motor's symptoms have not improved at all.
It's the same.

RPM does not go up.

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喜马拉雅之雪
Employee

I understand that your testing. However, don't floating the ground of the probe.

I think about,this is only testing skill, it's not big problem.

Could you tall me about what's your ran of max speed?

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JasonLEE
Level 4
Level 4
First like received First solution authored 50 replies posted

The maximum speed I want is 2500 RPM.

But it only goes up to 1000 RPM.
It's not going up any more.

Can't you solve this problem?

 

Where should the grounding of the probe be located?

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喜马拉雅之雪
Employee

My favort is power ground(-bus) with PWM power waveform. Other testing, I like use local ground(test reference ground is nearest the test target).

For 850rpm, could you test current and PWM waveform?

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JasonLEE
Level 4
Level 4
First like received First solution authored 50 replies posted

Which part are you talking about if it's local ground?

Can you explain it in more detail?

Are you talking about the Earth part?

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喜马拉雅之雪
Employee

MCU and shunt picture... 

For example, shunt wavefrom:

This is test via layout with the shunt resistance:

_0-1672211481247.png

Probe:

_1-1672212280913.png

 

 

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JasonLEE
Level 4
Level 4
First like received First solution authored 50 replies posted

Tested as you told me and exploded.

The whole hardware exploded.

d.jpg

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喜马拉雅之雪
Employee

WOW! DEEP LAMENT...

Could you share the shunt resistance part number? And shunt AMP loop SCH?

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