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CCS/DRV8353RH-EVM: DRV8353RH-EVM

Anish Bhatia
Prodigy 80 points
Part Number: DRV8353RH-EVM

Tool/software: Code Composer Studio

We are using 32V - 15A e-cycle motor (comes with 3 hall sensor) with Instaspin. I have updated user.h parameters as per motor specs.

Is there any way to increase torque per ampere in sensorless? In lab4 it becomes torque control drive. Thus is it possible to merge speed control as well torque control in any instaspin lab.

Do suggest some ways to increase current limit. Is it like , in sensorless we cannot achieve maximum torque per ampere?

  • 0
    TI__Guru 65410 points

    Anish,

    This question is best suited for the C2000 team, I will forward your question to them.

    Regards,

    -Adam

  • 0 in reply to Adam Sidelsky
    TI__Guru** 115470 points

    The torque constant is based on motor specification, it's difficult to change it by software. You can only improve the torque output by increasing the torque current, the maximum torque current is set by the USER_MOTOR_MAX_CURRENT in user.h.

    You can use the speed control in any lab as torque control, the lab05b~lab10a can support speed close loop control.

  • 0 in reply to Yanming Luo
    Prodigy 80 points

    Hello Yanming,

    Thanks for your answer. I have tried increasing USER_MOTOR_MAX_CURRENT to maximum hardware limit of DRV8353RH-EVM, i.e. 15A.

    Now the only challenge i'm facing is that when motor spins at around 100 rpm and if i apply full load with a person sitting on e-cycle, then the motor will give jerks in sensorless mode.

    And the DC current at that instant doesn't reaches the MAX LIMIT of 15A. It only goes upto 4A. Is that possible we can make the current limit to reach MAX even in the case of lower rpm and full load,

    so that motor shaft doesn't stops?

    NOTE: We have calculated the motor flux, Ls, Rs from GUI.

  • 0 in reply to Anish Bhatia
    TI__Guru** 115470 points

    You need to tune the Kp&Ki of speed regulator and do the same work at current regulators. It's not easy to run the motor smoothly at around 100rpm with full load using sensorless-FOC, that's why most e-cycle use hall sensor for low speed.

    You can apply the maximum current to any speed, but the FOC is a current close loop, the real required torque current depends on the motor speed and load. 

  • 0 in reply to Yanming Luo
    TI__Guru** 115470 points

    I haven’t heard back from you for about two weeks, I’m assuming you were able to resolve your issue. If not, just post a reply below (or create a new thread if the thread has locked due to time-out). Thanks.