Formulas of Ki, Kp, observer gain

Discussions regarding the Field Oriented Control (FOC) implementation on the VESC.
Nathan
Posts: 4
Joined: 22 Nov 2017, 14:15

Formulas of Ki, Kp, observer gain

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.

Prevas_erra
Posts: 24
Joined: 11 Apr 2016, 16:03
Location: Stockholm

Re: Formulas of Ki, Kp, observer gain

In the Vesc tool source you can find these equations:
// https://e2e.ti.com/blogs_/b/motordrivec ... ve-part-ii
double tc = ui->tcBox->value();
double bw = 1.0 / (tc * 1e-6);
double kp = l * bw;
double ki = r * bw;

ui->kpBox->setValue(kp);
ui->kiBox->setValue(ki);

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

Eric

rew
Posts: 943
Joined: 25 Mar 2016, 12:29
Location: Delft, Netherlands.

Re: Formulas of Ki, Kp, observer gain

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?

pf26
Posts: 309
Joined: 28 Mar 2016, 14:37
Location: FR Valence

Re: Formulas of Ki, Kp, observer gain

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.