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CCS/LAUNCHXL-F28027F: Applicaton question about the instaspin-foc

ming chen3
Intellectual 775 points
Part Number: LAUNCHXL-F28027F


Tool/software: Code Composer Studio

Hello ,everyone.

I have used the lab05b program driving my motor with the launchpad-28027F and DRV8305EVM.

Because my finial motor application current is very big. So I use the LEM hall sensor to sample the motor phase curent.

and I have confirmed that the InstaSPIN-foc program supported the LEM current sensing method.

but considering the system cost ，I just use two LEM current sensor to sample the phase current B and phase current C , and I use the KCL to calculate the phase current A.

and I have change the HAL_readAdcData()  function in hal.h.

I have run the lab02b to identify my motor parameter and the lab03a to caculate the current and voltage offset . the motor can run well and the result is accurate.

and then I run the lab05b to spin my motor in speed mode ,my can spin well in speed mode.and the speed is stable.

but when I prepare to run the lab05a program to spin my motor in current mode ,the motor can not spin,even though I set the iq_ref_A is equal to 10A.

I confirm my motor and my motor controller is good and they can work well in lab05b speed mode.but it can not spin in lab05a current mode.

I just change the shunt resistor to the  two LEM current sesor to sample the current B and C compare to the Launchpad-28027F and DRV8305EVM.

Please give a hand to solve the lab05a problem.

Thanks for your help!

Best Regards

  • 0
    TI__Guru** 116090 points

    Any load on the motor? and are there any filters on the current sensing signal chain? what sampling delay time is from LEM sensor? You may try to add a ramp control to generate the reference current or tune the Kp and Ki for the current loop. 

  • 0 in reply to Yanming Luo
    Intellectual 775 points

    Thanks yanming.

    1.My motor is no load,even though I change a small motor,It can not work too.

    2.I have not use any filter in the current sensing signal chain,but It can run well in lab02b and lab05b.

    3. The LEM current sensor response time is less than 5us.

    4.I use the lab02b inentify motor parameter to auto caculate the current loop PI.Perhaps it is not the reason.

    At first I think the motor is starting failed.I try to change the threshoud.but it make no effort.

    I wonder that whether it has anything diffierence between the lab05a and lab05b in motor starting algorithm.

    I will try to add a ramp control to generate the reference current .

    Thanks.

  • 0 in reply to ming chen3
    TI__Guru** 116090 points

    Please try to increase the gMotorVars.IqRef_A from a small value to the right value by manual, and add a light load on the motor. And please post a motor current waveform and describe what problem detailly you met.