Understanding Motor Parameters (Sine)

[OtterTech]

TLDR: There are a lot of parameters to configure / tune a motor. What do they do and how do I tune them?

Long version:
I recently started working on a dynamic test stand for repaired Tesla LDUs. The control is handled through an openinverter board.
My current testing motor is an LDU performance, but I had a base inverter connected at one point, which worked better with the default parameters.
I know of the setup/tune guide on the wiki, but this obviously won't work for me as I don't have a car to make driving tests in.
I don't think there is a formal guide on how to tune a motor for my specific use case, but maybe someone can shed some light on the function of the parameters. On the wiki a lot of the parameters are only explained very briefly or not at all. Therefore I don't know how I would go about tuning or where to find appropriate literature on how to tune the parameters for different setups.

For example this is everything I was able to find about the boost parameter:

Code: Select all

Name    Unit   Min   Max     Default   Description
boost   dig    0     37813   1700      0 Hz Boost in digit. 1000 digit ~ 2.5%

As well as tuning wise:
lower boost value in 100pts until motor jitters at start. Then return it to last good value.
add boost if motor is oscillating if it is smooth reduce it in 100pt increments untill you get oscillation. Then return to last good value

As far as I can tell, there is no detailed explanation of the exact functionality of the boost parameter in terms of the output signal or control theory.

If there is anyone who can shed some light on the functionality of many of the parameters, but in my case mostly

1. boost
2. fweak
3. fslip...

but there are for sure others that will become relevant later on.

[tom91]

https://openinverter.org/wiki/Parameters

Ask questions with context please, what are you trying to achieve?

You want to tune an LDU, okay what is the base param set you are using and what does it not do that you want it to do?

There is also plenty videos of Damien and Johannes setting up different drive units and explaining the parameters.

[tom91]

Some info I found on my PC around tuning

Parameter settings
Fmax = 600hz or 18K rpm
Fweak = 250hz - motor base speed
FSlipMax = 3-5 - application dependent, tune it for low end acceleration

Tuning
Fslipconstmax
Needs to be larger then FSlipMax, increasing it will give more top end power.
Increase it starting at 1 or 2hz increment until you can reach Fmax
Fconst
This needs to be higher then Fweak, set it at Fweak + 100 to start. Move the value closer to Fweak if there is a dip in power in the mid range. If there is a drop off after midrange move it further away.

[OtterTech]

Ask questions with context please, what are you trying to achieve?

You want to tune an LDU, okay what is the base param set you are using and what does it not do that you want it to do?

I think I answered what I'm trying to acheive. I'm building a dynamic test stand to validate motor repairs unsing frequency analysis. Therefore I'm not running the motor in a vehicle and I also do not have any load connected to the motor. There is also no drive shaft connected. I dont have a base parameter set except the Tesla Board defaults, i.e. I'm starting from scratch.

One thing I have to admit is that I overlooked the explanation at the top of the page and I will start by doing some experimenting around the recomendations from there.
But I don't think I will be able to fully tune the motor with the information given there. If someone has some recomendations for papers or books on the topic that would be great.

[tom91]

Again what are you trying to achieve.

I'm building a dynamic test stand to validate motor repairs unsing frequency analysis

Explain further please, I understood the unloaded part. Which will make tuning a pain in the arse as its so powerful it will spin up really quick unless you limit throttle alot.

Example, you want to run a sweep? or a fixed rpm? ect.

[OtterTech]

Example, you want to run a sweep? or a fixed rpm? ect.

I'm not quite sure right now. A sweep would corespond with many approaches of control theory but using PLL in my analysis would require several different fixed RPMs. In the end I want to capture vibrations to identify faulty bearings and unbalanced rotors, if possible even if a technician is not yet able to identify the problem.