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Original question:

TMS320F28069M: Encoder feedback angle isn't right when running lab12b

TMS320F28069F: Motor reverse rotor position calibration failed

hongwei Quan
Prodigy 190 points

Part Number: TMS320F28069F

Dear  Yanming Luo:

I am conducting sensor FOC control experiment. The motor is IPMSM. I refer to the existing thread in the forum:

e2e.ti.com/.../tms320f28069m-encoder-feedback-angle-isn-t-right-when-running-lab12b ,

but I need your help when I encounter problems.

1. Is it normal for the motor speed to rise to the maximum speed very quickly when the rotor position calibration is incorrect? 

2. I use the above thread scheme to obtain Angle_est from sensorless control mode when the motor rotates forward for 2s, and complete offset calibration (Counter=angle_est * 4 * encoder_line/(2 ^ 24)/Pole_ Pairs), and switch to the sensor control mode at the same time, which is very good. However, the same method is used to perform offset calibration when the motor is running in reverse direction. The calibration fails and the motor has Q1 phenomenon. How can the motor run in reverse from the obtained Angle_ est calculates the count value?

Regards

Quan

  • 0
    TI__Guru** 117160 points
    hongwei Quan said:
    1. Is it normal for the motor speed to rise to the maximum speed very quickly when the rotor position calibration is incorrect? 

    Yes. The feedback speed will be incorrect to cause the output of speed loop is very high.

    hongwei Quan said:
    How can the motor run in reverse from the obtained Angle_ est calculates the count value?

    Refer to lab12a to use the Rs recalculation to force the rotor angle to zero position for offset calibration when start the motor.

  • 0 in reply to Yanming Luo
    Prodigy 190 points

    Hi,Luo:I did the experiment again_ Est is converted to (angle_est+_IQ (1.0))&0x00ffffff, and then the count value is calculated. At the same time, offset calibration is performed, and then switch to the sensor control mode. In this way, whether the motor is running in the forward or reverse direction, it can correctly calibrate the rotor angle and operate well. However, there is a problem that I hope to get help: if the motor does not rotate, it will cause the rotor position calibration failure, but if the sensorless start is used, even if the rotor does not rotate, the est is also performing angle estimation, which will not cause the rotor position calibration failure, is that right?

    Regards

    Quan

  • 0 in reply to hongwei Quan
    Prodigy 190 points

    Add explanation: With Rs calculation, if the motor does not rotate, the rotor position calibration will fail

  • +1 in reply to hongwei Quan
    TI__Guru** 117160 points

    Yes. You need to set the right USER_MOTOR_RES_EST_CURRENT to force the rotor to zero position.

    #define USER_MOTOR_RES_EST_CURRENT     (2.0)                               // A - 10-50% of rated current of the motor