Implement a Motor drive with constant speed

Hello,

for a project I need to implement an induction motor which operats under variable torque while keeping its speed at 1500rpm. A sensor measures the speed and gives signal to the inverter that drives the induction motor in order to maintain the constant speed under varaible torque. I couldn't find examples similar to this case so I hope you could answer these following questions:

• which library would you recommend, sps or ss electrical? and why? sps has the advantage that it has squirrel cage models, but although I went through the documenetation countless times I still get wrong results with the mechanical port so I thought ss electrical would be easier
• which control type would you recommend? I'd rather have one with the least number of parameters since I don't have the parameters of the drive myself so I though the scalar control with a speed feedback loop would be okay
• assuming I'm using the rotational port S (the green one) and my motor gives a constant speed and variable mechanical torque, do these transmit through the shaft like in reality or not?

if you have any general remarks to this case it would be really helpfull

thank you!

Answer 1

[Anurag]

Hi K,

I understand you want to implement a motor drive with a constant speed. The following steps can serve as a workaround to resolve your issue:

• Choose “ss_electrical” if you prefer a simpler electrical model and are facing issues with the mechanical port in “sps”.
• opt for scalar control with a speed feedback loop for simplicity and fewer parameters, suitable for maintaining constant speed under variable torque.
• Using the rotational port S in Simscape transmits torque and speed through the shaft, simulating real-world behaviour.

Please refer to the following MathWorks documentation link below which consists for of an example for on implementing a motor drive:

https://in.mathworks.com/help/sps/ref/motordrivesystemlevel.html

Hope this helps!

[K]

thank you for you answers

it's specified in the documentation of the the Motor & Drive block that it is operating in torque control mode, is it viable to use it in a speed control mode (with a speed control block)