Formulas of Ki, Kp, observer gain

Discussions regarding the Field Oriented Control (FOC) implementation on the VESC.
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Joined: 22 Nov 2017, 14:15

Formulas of Ki, Kp, observer gain

Postby Nathan » 22 Nov 2017, 14:53

Hi to all! Can anybody give formulas for parameters Ki, Kp, observer gain? I can't calculate them in VESC Tool. I think, because a motor, which I use (GBM110-150T), have very high inductivity - 12000mH.

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Joined: 11 Apr 2016, 16:03
Location: Stockholm

Re: Formulas of Ki, Kp, observer gain

Postby Prevas_erra » 22 Nov 2017, 16:24

In the Vesc tool source you can find these equations:
// ... ve-part-ii
double tc = ui->tcBox->value();
double bw = 1.0 / (tc * 1e-6);
double kp = l * bw;
double ki = r * bw;


void DetectFoc::on_calcGainButton_clicked()
double lambda = ui->lambdaBox->value() / 1e3;
//Lambda in Weber
ui->obsGainBox->setValue((0.001 / (lambda * lambda)));


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Re: Formulas of Ki, Kp, observer gain

Postby rew » 25 Nov 2017, 11:38

Nathan wrote:have very high inductivity - 12000mH.

That is VERY high. So if we apply 12V, after about a second the current will have risen to 1A. So more than about 20 - 30 RPM is imposible with this motor. Are you sure?

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Location: FR Valence

Re: Formulas of Ki, Kp, observer gain

Postby pf26 » 26 Nov 2017, 14:31

From the link with the motor website, it is said to have 17.8 ohms winding ! If true, I doubt the motor will tolerate more than a few amps for more than a few secs. And this is not suitable for the VESC unless you change the shunts. Possibly 12000mH is in fact 12mH (12000uH), which is already quite a lot.

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