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Can the PMSM model be modified for an Open Winding Configuration?

0 votes
I am trying to model a three-phase PMSM with an independent open winding configuration (no internal neutral). Looking under the MASK of the PMSM model, it appears that this should be easily accomodated with the "Voltage Behind Reactance" by removing the internal neutral connection, and making the resulting three electrical connections (one for each phase) available at the model inputs. I tried to do this manually, but the connection between the model input parameters is lost. Can this model be made available?
asked Apr 23, 2020 by tbeechner (16 points)

1 Answer

+1 vote

I can describe the mechanics of modifying the model, but first you should be aware that both the “Rotor Reference Frame” (RRF) and “Voltage Behind Reactance” (VBR) PMSM models are derived assuming that the sum of the stator currents is zero.  Therefore, simply modifying the existing model by breaking out the neutral connection will not result in an accurate model.

Note that the "Non-Excited Synchronous Machine” is implemented in a way such that the neutral point can be connected, since it is not based on this assumption.  Therefore you should modify that model instead using the following steps:

  1. Copy the library component to your schematic, right click the component and select Subsystem + Break Library Link. 
  2. Right click the component again and select Subsystem + Unprotect.
  3. Navigate to the Electrical Model subsystem and add the additional Electrical Ports to the neutral point (e.g. a', b', and c').
  4. Navigate one level up and add the top-level Electrical Ports to the component.
  5. Within the Electrical Model, modify the DQ Inverse Saturation Lookup function to be a linear model by replacing the lookup tables with the flux being a linear function of current (phid = Lmd*id+phim & phiq = Lmq*iq) and setting the Lmi output to [Lmd, 0, Lmq].  Here phim is the flux induced by the permanent magnet, Lmx is the mutual inductance, and Lls is the stator leakage inductance (Ld=Lmd+Lls, Lq=Lmq+Lls ).  Note that you'll have to define/enter the Lmd and Lmq components, but the stator leakage component (Lls) already a mask component.
answered Apr 23, 2020 by Bryan Lieblick (1,301 points)
edited Apr 24, 2020 by Bryan Lieblick