PMSM HUB Motor startup noise and vibration issue

[gappati]

Hi,
We have designed the HUB motor ( PMSM ) controller . It is supposed control the ebike. We have used Space vectror modulation
technique to control the motor. The position management based on digital hall sensor. The motor has 48 poles and has an operating voltage of 48V.
PWM switching frequency is 16KHz.

We are actually stuck with one problem. Initially when you start the motor up to 40rpm, we get some noise and vibration and then later it becomes
pretty smooth. The problem iam explaining is only on loaded condition. In free spin, it is smooth all over. The noise that we get is some thing similar
to flight flying in stable condition. Initially for two mechanical rotation we modulate the PWM on every 60deg electrical angle after that when we start getting the rotar angle position, we modulate PWM for every 62.4us.

The problem is not with the motor because it runs smoothly with China controller.

Please let me know, if any-one has experience of facing such problem and resolving it

 

[Easy peasy]

It's your software. There - solved !

 

[gappati]

Not sure i understand this

 

[KlausST]

Hi,

it means: the vibration problem is caused by your software.

So - as long as you don´t show us your software - we can´t help you with this.

Klaus

 

[gappati]

OK. Let me give you overview of my software.
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1. The software control has PI block and SVPM. PI block gets required speed from throttle input and current speed ( calculated from
HALL sensor input)
2. We use moving average of speed, calculated in every 180deg electrical angle.( Last 6 samples ) .

3. Angle estimation is done on every 60deg electrical angle.
4. We use 3 phase conduction method .
5. while starting the motor, first 720deg electrical angle we modulate the PWM on every 60 deg, after crossing 720deg we modulate
the PWM on every 62.4us which means higher resolution electrical angle.

Motor performance is very smooth after 40rpm. Before that it has some vibration/jerk followed by noise.

 

[KlausST]

I don´t think it´s a good idea to give a textual description about what you expect your code to do.

--> show your code.

Klaus

 

[gappati]

Sorry Mr. Klaus. Iam not supposed to show the code as Iam bonded to company policies. Iam expecting.
if there are some techniques or better way of doing things in the form of past lesson learnt.

 

[Easy peasy]

past lesson learnt are: if you can't see the bugs in the software - you can't fix it !