TMS320F28065: Problem with control a pmsm motor using foc method

Hamid Kavian Athar

Part Number: TMS320F28065

Hello TI experts,

I am going to control a PMSM motor using foc algorithm. I have designed a board which contains a f28065 microcontroller. In order to do that I started with ti application notes. Then I customised it according to my board.

I got started with HVPM_Sensorless project. I have followed the application note untill LEVEL4 successfully. Since my motor is not equipped with encoder, I move on to LEVEL 6. First, I set lsw to 0 then in watch window I change it to 1, finally when the rotor speed is close to speedRef, I set it to 2. In this process I have ran into some problems.

1- sometimes, when I set lsw to 1, motor starts vibrating and makes a lot of sounds and it doesn't rotate at all.

2- when lsw is set to 2 and rotor is rotating, if I physically stop the rotor and release it, it becomes unstable and also rotates in opposite direction.

Could you please tell me what I should do?

Thanks in advance.

over 2 years ago

0 Yanming Luo over 2 years ago

TI__Guru** 115440 points

Do you have to design and work on your own board? Or on a TI EVM board?

Do you have a look at the application note of the example code? Do you try to change and tune the parameters for the SMO according to the motor you used?

0 Hamid Kavian Athar over 2 years ago in reply to Yanming Luo

Intellectual 520 points

Thank you for your help.

Unfortunately, I don't have any TI EVM board.

In level4 of application note I adjusted the parameters of SMO.

Here are pictures of rg.out and smo.theta. when there is no load.

The yellow waveform is the estimated theta and blue one is RG.out.

If I add some load to the motor, the phase difference between them will decrease. It is shown in the following picture.

0 Yanming Luo over 2 years ago in reply to Hamid Kavian Athar

TI__Guru** 115440 points

Seems the SMO doesn't work well. You have to keep tuning the SMO parameters to make these two angle are very close in this level.

0 Hamid Kavian Athar over 2 years ago in reply to Yanming Luo

Intellectual 520 points

Thanks for the reply.

I tried tuning SMO parameters. Here are the pictures of the estimated theta and RG.out:

speedRef is 0.3 and Iqref is set to 0.3 pu. Two angles are so close. Could you tell if it is tuned correctly or not?

I've got another problem. Sometimes when start driving the motor, it doesn't rotate and generate a lot of noise. Could you please give me any advice?

0 Yanming Luo over 2 years ago in reply to Hamid Kavian Athar

TI__Guru** 115440 points

Not good. The angle from the eSMO should be close to a lineas as well as the angle from RG model. Please make sure that the motor parameters are correct, and keep tuning the related variables of the eSMO.

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TMS320F28065: Problem with control a pmsm motor using foc method