Learning Forum

[Ruchika Singh]

I am trying to simulate a PMSM in 2D transient with Ansys Maxwell 2023R2 version. I have defined my coils as stranded in the excitation. My questions are as follows:

 

1. What is the difference between Stranded loss, StrandedAC loss and StrandedR loss? Here, I have not defined any wire cross-section, so I am assuming the resistance is calculated by considering the fill factor as 100% of the area defined as the coil. Am I correct here? If this is the case, then the resistance is not correct as the fill factor is never 100% in reality. How can I correctly calculate the resistance without modelling the coil? The excitation is the current excitation here.
2. When the motor is excited with current, the induced voltage for the winding is the sum of back-emf + the resistance drop. Is this correct? If this is the case, then which resistance is used here to calculate the resistance drop? What is the correct way to calculate the induced voltage with load (with current excitation here)?

 

Thank you very much!

[GLUO]

Hello,

1. 

• StrandedLoss is dependent on the object’s material conductivity of a stranded source. It represents the loss due to the DC resistance only and uses the cross-sectional area of the object that is assigned with the excitation. Where J is the current density, it is 1/bulkconductivity*integral of J over the volume

 

o When Litz wire is not defined, StrandedLoss is computed by assuming fill factor = 100% (the ratio of net conductor area to coil terminal area).

o When Litz wire is defined, StrandedLoss is computed by using the actual fill factor based on the specified Litz stranding and represents the DC loss only.

o StrandedLoss does not include the losses of end-coil resistance in 2D.

o StrandedLoss can be used to scale the loss density to a coupled thermal analysis.

• StrandedLossAC is reported when using Litz wire model, and is dependent on the object’s material conductivity of a stranded source. It represents the loss due to the DC resistance as well as AC eddy current losses due to proximity effects and skin effects.

o StrandedLossAC = StrandedLoss + AC eddy current losses due to proximity effects and skin effects.

o StrandedLossAC does not include the losses of end-coil resistance in 2D.

o StrandedLossAC can be used to transfer loss density to a coupled thermal analysis.

• StrandedLossR represents the loss based on I2 times the resistance R, by using the resistance value entered in the Winding properties for a voltage type winding only (Reported for a stranded voltage source not in an external circuit).

2.Induced voltage does not include the resistance drop.

GL