FOC - Max Torque Per Ampere

[peterkostadinov]

Hello,

According to what I found in the datasheets, in order to have max torque per ampere, stator's flux has to be applied on 90 degree to rotor's flux (PMSM motor) and on 45 degrees (ACIM motor). So, with use of an observer (or an encoder), current angle is determined, then this angle is used to convert stationary AlphaBeta frame in to rotating DQ frame (Park conversion), Id/Iq are corrected, and with Park_Inverted rotating frame is back converted to stationary AlphaBeta frame. In both conversions Park/Park_Inverted is used the same angle. I'm wondering where (in which API) is added 90 degree to the current angle. Maybe the moment in which Id/Iq are corrected, in fact is indirect angle correction?

I am working with MKV46F256VLL16, MCRSP_ACIM_V1.2.0/MCRSP_PMSM_V1.2.0 and MCUXpresso_IDE.

Best Regards,

Peter

[xiangjun_rong]

Hi, Peter,

The remark " stator's flux has to be applied on 90 degree to rotor's flux (PMSM motor)" is valid for both PMSM and ACIM when the polar pair is 1. In other words, the electrical  angle between the stator and rotor flux should be 90 degree for both PMSM and ACIM. With the FOC transformation, you can get the Id/Iq, which are 90 electrical degree, in this way, you can get decoupled torque component Iq and excitation component Id, so you can control them independently. You are correct that "In both conversions Park/Park_reverse used the same angle"

Hope it can help you

BR

XiangJun Rong

[peterkostadinov]

Hi XiangJun Rong,

Thank you for the information!

Best Regards,

Peter