In Field oriented control of induction motor it's necessary to do:

  1. Clark Transformation
  2. Park Transformation

According to the note (page 3): http://ww1.microchip.com/downloads/en/AppNotes/ACIM%20Vector%20Control%2000908a.pdf To calculate Park trans. (flux and torque stator current components /Id, Iq/) rotor flux angle is needed - it's described at page 4 how to calculate it.

My misunderstanding is how to do it if at these equations (EQ 1: Magnetizing current, EQ 2: flux speed) there is a necessity to have Id, Iq current which we haven't (as I mentioned to calculate it rotor flux is needed)?

What are the steps to do it exactly?

  • \$\begingroup\$ Not clear what is the question but: You get Id and Iq through Clarke->Park transformation. The flux can be estimated with use of estimator. \$\endgroup\$ – Marko Buršič Sep 3 '17 at 18:24
  • \$\begingroup\$ Thanks for reply. My question was how to calculate rotor flux angle which is needed to calc. Clarke->Park transformation. \$\endgroup\$ – Fasset Sep 3 '17 at 18:27
  • \$\begingroup\$ You get it from the encoder. Actually you need to know the slip frequency, which is \$\omega_S - \omega_R \$ \$\endgroup\$ – Marko Buršič Sep 3 '17 at 19:28
  • \$\begingroup\$ To be more precise I'm trying to write my own soft to FOC. \$\endgroup\$ – Fasset Sep 3 '17 at 19:54
  • \$\begingroup\$ Too complicated, good luck. \$\endgroup\$ – Marko Buršič Sep 3 '17 at 19:57

Start with a flux angle of 0. As there is no current in the machine at the beginning, this is correct. Then you can do the Park Transformation and calculate Id and Iq. With these you can calculate the flux angle for your next iteration. Texas Instruments described it under 3.9.1 here: https://www.google.com/url?sa=t&rct=j&q=&esrc=s&source=web&cd=4&ved=2ahUKEwiZuuCU_YfdAhUi_SoKHTN0CewQFjADegQIBxAC&url=https%3A%2F%2Fwww.researchgate.net%2Fprofile%2FSai_Sudheer_Reddy_Bonthu%2Fpost%2FWhat_are_the_methods_to_implement_PARK_transformation_on_C2000_DSP_micro_controller%2Fattachment%2F59d64d7079197b80779a7006%2FAS%253A488146115796992%25401493394511043%2Fdownload%2FFOC.pdf&usg=AOvVaw2TEZzD_6dVsD1KEAMmm-IQ

  • \$\begingroup\$ ehm...the texas link is broken, can you fix it? \$\endgroup\$ – Deep Jul 21 '18 at 6:43
  • \$\begingroup\$ Seems as TI removed the article from their website. ST has a similar application note, the rotor flux angle estimation by the current model is descibed in 2.4: st.com/content/ccc/resource/technical/document/application_note/… \$\endgroup\$ – Tim Aug 15 '18 at 11:44

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