Asynchronous Machine Motor Parameters Direction Reversal

I am currently trying to create a model for a Marathon 5K33GN2, which was originally provided by TI as part of one of their motor control kits. I am using a three phase asynchronous machine block from Simulink to represent the motor. Using the power_pwm example project as a baseline, I created a simple simulation driving an induction motor with a three phase 220V 60Hz source and observing the resulting RPM. The results from the baseline power_pwm example were as expected, but I ran into issues while trying to adjust the motor parameters to match those of the Marathon motor. Specifically, there seem to be certain ranges for stator resistance and rotor inductance that cause the motor to report a negative velocity while continuing to accelerate indefinitely (without ever reaching a steady state RPM). The issue seems to manifest when the stator resistance is set at 2.7 Ohms or higher (the stator resistance of the Marathon motor is 11.05 according to TI). Clearly the behavior is not correct and the real motor does not react this way. I also noticed that the "Nominal power, voltage (line-line), and frequency" parameters do not seem to have any effect on the response. I tried reading some of the corresponding documentation but coulnd't figure out why the model does this or how to fix it. Any help would be appreciated.

Simulink Model

Normal Acceleration

Reversed (i.e. stator resistance 11 Ohms)

Answer 1

[Keerthana Chiruvolu]

Hi,

When trying to adjust the motor parameters to match with those of the Marathon motor, kindly adjust all the parameters of the motor(R, L, Lm, Inertia, Polepairs, Slip), run the simulation to check if the output matches with the Marathon motor. Improper values of any of the parameters may cause this undesirable behavior.

The motor used in the Simulink model is Asynchronous Machine pu Units. There is another motor available, Asynchronous Machine SI Units. Kindly consider this when assigning the motor parameters.

[Benjamin Paik]

The motor used in the Simulink model for the "Three-Phase asynchronous machine" (opens as power_pwm) is actually the SI unit version. This is the same one I used in my modified Simulink model. When opening the block parameters, all the units are listed as "Ohm" and "H". I've checked the parameters against the motor spec many times and so I'm pretty confident they are correct. Also, I don't think any combination of motor parameters should result in the motor accelerating forever, which is what happens when adjusting the parameters as I originally described in my question.