BLDC model with simscape

Hi all,

I recently started making a model for a BLDC motor, which is supplied by DC voltage, with simscape on R2013b. After some research I came up with the following model:

where the hallsensor output of the BLDC creats the EMF signals and then the gate signals

I got some values for the BLDC from a data sheet and entered them into the PMSM motor block. Everything seems to be working fine except the speed of the rotor. It somehow is way to high (at no load about 25000 rpm whereas I would expect about 4200 rpm). Is there anything I am missing? The current is alright as well as the voltage, so I assume there is issue with the PMSM motor block somehow, but as I have it from the powersystems toolbox I am not sure if there is something wrong with it. Or is something wrong with the logic table?

Thank you for your help in advance!

[Dimitrios Petridis]

I forgot: I already changed the load on the motor and it seems that the speed doesn't react linear to the applied load.

[rajab84]

I am facing the similar problem, Could you please elaborate on changing the load on motor?

[sandesh khadka]

can you please send me your slx file.

[e-mail]

Answer 1

[Monica S]

From the model you shared I don't quite get the idea from where load torque and reference speed are taken from, anyway you can control the speed by tuning the PI controller (either by designing the controller or using trail & error method to tune the values).

There is a model of BLDC motor speed control in mathworks which you can use it as refernce, you can type "power_brushlessDCmotor" in command window.

Use a constant block to input speed reference value (say, give it as 4200 rpm for no load speed) Then test it...

Let me know if you need any help.

Answer 2

[sandesh khadka]

[sandesh khadka]

what is this happening

[Zhao Wang]

The signal dimension does not seem to match. Its dimension should be 3 but here it is only one. Please check the signal dimension that connects through the input port "hall".