TMS320F28035: Back-EMF Observer method in Dave's Simulation files -- 45 PMSM digital EMF observer

Jack Tan80

Part Number: TMS320F28035
Other Parts Discussed in Thread: CONTROLSUITE

Dear Champs,

When using Dave's simulation files, 45 PMSM digital EMF observer(e2e.ti.com/.../666402), I found that the simulation result is pretty good.

Now I have 2 questions about the single phase motor:

1.Can you please let me know what the original model of low pass filter is in S domain? In my understanding, it should be LR circuit, the equivalent resistance in s domain should (sL + R), but whatever using forward rectangular rule, backward rectangular rule, and bilinear transformation, I can't get the exact model with your simulation files.

2. The estimated back-EMF(the PI output) used for the input of low pass filter model is the last calculated value, I have highlighted this in below picture, can you please help me know why?

over 7 years ago

0 Yanming Luo over 7 years ago

TI__Guru** 117240 points

1. You might refer to the mathematical model of a motor in some motor books. Considering a general form of a closed-loop with the PI controller for a motor and RL model as a plant, the closed-loop transfer function of the reference response is derived in a Laplace form, will get the series Ki equal to R/L.
2. The Z-1 is the discrete-time operator to accept and output signals with a discrete sample time.

0 Jack Tan80 over 7 years ago in reply to Yanming Luo

Mastermind 7160 points

Yanming Luo said:
1. You might refer to the mathematical model of a motor in some motor books. Considering a general form of a closed-loop with the PI controller for a motor and RL model as a plant, the closed-loop transfer function of the reference response is derived in a Laplace form, will get the series Ki equal to R/L.
Jack-> The comments in the simulation files are low pass filter, why does using PI loop? Can you please provide the exact transfer function in s domain?

Can you please recommend a book/paper that describe this?

2. The Z-1 is the discrete-time operator to accept and output signals with a discrete sample time.

OK.

0 Jack Tan80 over 7 years ago in reply to Jack Tan80

Mastermind 7160 points

Hi Yanming,

May I get your further comments?

0 Jack Tan80 over 7 years ago in reply to Jack Tan80

Mastermind 7160 points

Hi Yanming,

Can you please share your comments on this?

Jack-> The comments in the simulation files are low pass filter, why does using PI loop? Can you please provide the exact transfer function in s domain?

Can you please recommend a book/paper that describe this?

0 Jack Tan80 over 7 years ago in reply to Jack Tan80

Mastermind 7160 points

Dear Champs,

Is there any feedback about my question? Please let me know what your concern is, my question has been pending for almost 1 week.

0 Jack Tan80 over 7 years ago in reply to Jack Tan80

Mastermind 7160 points

Any feedback?

0 Jack Tan80 over 7 years ago in reply to Yanming Luo

Mastermind 7160 points

Any feedback about this?

The comments in dave's simulation files are low pass filter, why does using PI loop? Can you please provide the exact transfer function in s domain?

Can you please recommend a book/paper that describe this?

0 Yanming Luo over 7 years ago in reply to Jack Tan80

TI__Guru** 117240 points

You may have a look at the chapter on SMO in the document in controlSUITE. For more detailed information, you might to read the "AC ELECTRIC MOTORS CONTROL" written by Fouad Giri.
C:\ti\controlSUITE\libs\app_libs\motor_control\math_blocks\v4.3\~Docs

0 Jack Tan80 over 7 years ago in reply to Yanming Luo

Mastermind 7160 points

Hi Yanming,

Thanks for this book. I will read it, can you please provide the exact transfer function of Dave's motor model in s domain?

0 Yanming Luo over 7 years ago in reply to Jack Tan80

TI__Guru** 117240 points

You might deduce it based on your motor spec. and recommended books, we didn't have it, just built the model directly.

0 Jack Tan80 over 7 years ago in reply to Yanming Luo

Mastermind 7160 points

OK, thanks for recommending this book.

C2000™︎ microcontrollers

C2000 microcontrollers forum

TMS320F28035: Back-EMF Observer method in Dave's Simulation files -- 45 PMSM digital EMF observer