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Inertia and cut-off frequency parametrs in Motor SDK 5.Y.3 for E-Scooter application

DTort.1
Associate III

I am trying to find the correct PI controllers parameters for my E-Scooter application. Initially, I determined the parameters of the motor through the Motor Profiler, but now I wondered what inertia should be specified. The inertia of the engine idle is quite small, but when the E-Scooter moves with a passenger, the inertia of such a system is many times greater. Since the calculation of PI controllers depends on this, I would like to better understand how I should calculate it. I am also interested in the cut-off frequency parameter, since I have a low-speed application of only 500-600 rpm max, which frequency should I set if I do not need high-frequency pulsations that may arise during control.

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5 REPLIES 5
Laurent Ca...
Lead II

Dear @DTort.1​ 

Sorry for the late answer.

Do you have still this problem to solve?

And just in case, if not, do not hesitate to share the final solution you found. Thanks by advance.

Best regards

Hello, yes I would still like some clarification on how to set up the Motor SDK for electric scooter motors where there is significant system inertia at start up. The motor with Hall sensors starts well at idle, but under load, the torque is very weak.

Quentin Ch
Associate III

Hello, I get the same issue.

Motor alone (without gearbox and not linked to my load) will spin, but fails to move when load is connected (motor is supposed to drive a trolley of several kg). Did you find a solution ?

By the way, the units of the inertia and friction identified by the Motor Profiler are of the order of few "micro". This seems very low and not very plausible. I wonder if this is a typo...

Alex1603
Associate II

Hello! I am also intresting in this question. I cheked all wiki.st.com and didn't find mention about how paramitre inertial and friction are taking in accaount in FOC algorithms. Please clarify this issue.

FVan .1
Associate II

Hello,

I have also some questions about Motor Profiler results.
We profiled a motor with to less parameter specifications. During profiling the motor was rotating fine.

With the profiling file we made a new project for a different inverter.

When we start the motor in Motor Pilot the motor is starting CW but after a while it switches to CCW. Finally, it stops due a USB connection failure with the control board.
See attached video (result,zip)
Anybody an idea how to solve this?  

For the moment I have some doubt about the profiled inertia value.
The value is extreme low and the units are strange.
Anybody a idea how to validate the profiled value?