infineon4engineers

# Thread: [SOLVED] Questions about phase inductance and phase resistance in FOC Code

1. ## [SOLVED] Questions about phase inductance and phase resistance in FOC Code

Hi I have some questions about FOC.

In the example code, we know that we set the Phase Resistance to 0.36 ohm and the Phase Inductance to 0.0002H. And what motor was used was confirmed in Abstract.txt.

1. Is Phase Resistance the half of Line to Line Resistance?
2. Can I obtain the phase resistance value using the stator resistance value?
If I can get it, let me know how to get it.
3. I want to know how to obtain the value of phase inductance.
4. I want to know how to obtain phase inductance using direct axis inductance.

Regards,
Rocky

2. Hi Rocky,

The FOC democode is expecting the motor windings in a star connection.

1) Yes, the Phase resistance is half of the Line to Line resistance

2) There is no distinction between stator and rotor resistance value in the code

3) it is possible to measure the phase inductunce in several ways:
- measure it with a LCR-Meter
- Apply a 50% dutycycle PWM-pattern, measure di/dt with a current Probe and calculate L

4) For this point, I have to reference the literature: "Permanent Magnet Synchronous and Brushless DC Motor Drives" from Ramu Krishnan
On Page 35, he gives a hint:

- Generally, the ratio is in a range of 3
- Earlier in the book he writes Ld > Lq

4. Originally Posted by Mc-Key
Hi Rocky,

The FOC democode is expecting the motor windings in a star connection.

1) Yes, the Phase resistance is half of the Line to Line resistance

2) There is no distinction between stator and rotor resistance value in the code

3) it possible to measure the phase inductunce in several ways:
- measure it with a LCR-Meter
- Apply a 50% dutycycle PWM-pattern, measure di/dt with a current Probe and calculate L

4) For this point, I have to reference the literature: "Permanent Magnet Synchronous and Brushless DC Motor Drives" from Ramu Krishnan
On Page 35, he gives a hint:

- Generally, the ratio is in a range of 3
- Earlier in the book he writes Ld > Lq

and how to change this thread to [SOLVED]?