MCB SMPMSM model delta vs star

In the Motor Control Blockset Surface Mount PMSM model, does star vs. delta winding configuration matter? For example, the Simulink example mcb_pmsm_foc_autotuner_f28379d.slx...will that example behave differently on a delta motor vs a star motor?

Answer 1

[Neelanshu]

Hello Bill,

I understand from your query that you want to know whether changing the configuration from star to delta in the “PMSM” block has any effect.

For an electrical machine (no matter what type it is, PMSM or other types), the torque calculation is based on dq-axes currents corresponding to the stator winding currents.

For example, the torque calculation for a sinusoidal-back-EMF PMSM is given by:

The dq-axes currents ((), and () used in the above equation come from the Park transformation applied to the currents flowing through the internal stator windings (i.e., (), (), and ()).

So, for a Wye-connected machine, the currents flowing through the stator windings are the currents injected into the stator terminals ((i_A), (i_B), and (i_C)), i.e., (= i_A), ( = i_B), (= i_C). That is, the current flowing through the external ABC-line is the same as the current flowing through the machine windings.

Figure 1 Wye wound PMSM

 

However, for a delta-connected machine, the currents flowing through the stator windings are NOT the same as the currents injected into the stator terminals. They are given by (= i_{AB}), (= i_{BC}), (= i_{CA}); where (i_{AB}) is the current flowing from the stator's terminal A to terminal B internally, (i_{BC}) is the current flowing from the stator's terminal B to terminal C internally, and (i_{CA}) is the current flowing from the stator's terminal C to terminal A internally.

 

Figure 2 Delta wound PMSM

Hope this helps,

Regards,

Neelanshu

[Bill Hitchcock]

Yes that helps. So beyond simulation (PMSM model), as long as the same motor is used for parameter estimation and for FOC implementation, it wouldn't really matter whether it is a WYE or delta configured motor. Is that accurate? (I ask because I don't recall seeing that option anywhere in any of the PMSM example models)