Specification of the saturation characteristic for the model of the saturable transformer (Simulink Simscape Electrical - Specialized Power Systems)

Hello everyone,

I am currently conducting research and I would like to use the Simulink model of the saturable transformer. According to the Matlab Help Center, when specifying the saturation characteristic, the magnetizing current is required.

I would like to clarify whether Matlab is referring to the current through the pure inductance L_sat (an inductive current) or if it includes the total current through the parallel branch of L_sat and R_m.

Thank you very much in advance for your assistance.

Best regards,

Torben

Answer 1

[Vinay]

Hi @Torben,

The "Saturable Transformer" utilizes the flux and magnetization current (`Im`) flowing through the inductor (`L_sat`) to assess the flux linkage. Additionally, it accounts for the excitation current (`IRm`) passing through the resistor(`Rm`) to incorporate the iron losses.

Kindly refer to the below documentation of “Saturable Transformer” for more details:

https://www.mathworks.com/help/sps/powersys/ref/saturabletransformer.html#mw_1d213a6a-a0e6-4a24-9076-2322bcd06192

I hope this helps!

[Torben]

Hi,

thank you for your quick reply!

This means that Matlab needs an inductive reactive current as a magnetizing current without an active current component in the saturation characteristic. Due to the inductance, the reactive current would then have a negative sign.

Is this really how Matlab intends it?

[Vinay]

Hi, The reactive current can indeed have a negative sign. This negative sign often appears because the inductive reactance is typically modeled with jωL, where L is the inductance. When modeling magnetization, the sign convention is based on the voltage-current relationship across the inductance. If the phase of the current lags the voltage by 90 degrees (as it does in inductive circuits), this can result in a reactive power that is conventionally negative, representing inductive behavior.

[Torben]

Hi,

Thank you for your response.

I have just realized that the model does not assume negative current values for the saturation characteristic.

Thank you for your support!