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TIDM-TMS570BMS: Balancing (charge and discharge) Current Adjustment

Low Xiang Hooi55
Prodigy 130 points

Part Number: TIDM-TMS570BMS

Hi TI team,

Currently I'm doing active cell balancing testing for 16s battery using TIDM-TMS570BMS. I managed to perform active balancing at charge current ~3A for cell 16 (as per photo below). 

May I know how to adjust the balance current more than 3A? I understand that this EM1402EVM can balance the current up to 5A and I have tried to modify the example code(TMS570BMS) in sys_main, line114 from EMB_Vset(0, 2)  to EMB_Vset(0, 5). But It doesn't change anything on the balancing current (remain 3A). Kindly need your assistance on this.

Thanks.

Regards,

XH Low

  • 0
    TI__Genius 17370 points
    Hi XH Low,

    Welcome to the TI-E2E forums and thanks for the question! Can you please check the following things:
    - Have you checked if the thermals are okay to ensure no FETs are having issues at high current levels?
    -Have any modifications occurred on the EM1402 board?
    -Were there any other changes made to the example code? If so what are they?
    -Have you tried setting other smaller values for Vset to make sure the code is executing the DAC value properly?
    -Can you measure the current from the 12V battery?

    Thanks,

    Taylor
  • 0 in reply to Taylor Vogt
    Prodigy 130 points
    Hi Taylor,
    Kindly refer my answers below.

    - Have you checked if the thermals are okay to ensure no FETs are having issues at high current levels?
    [XH] Thermal is ok.

    -Have any modifications occurred on the EM1402 board?
    [XH]No modification on EM1402

    -Were there any other changes made to the example code? If so what are they?
    [XH]I only changed sys_main, line114 from EMB_Vset(0, 2) to EMB_Vset(0, 5)

    -Have you tried setting other smaller values for Vset to make sure the code is executing the DAC value properly?
    [XH]The DAC output voltage remain at 0.873V after modified Vset.

    -Can you measure the current from the 12V battery?
    [XH]The 12V supply current is 0.887A during charge cycle.

    My objective is to adjust higher balance current.

    Thanks.

    Regards,
    XH Low
  • 0 in reply to Low Xiang Hooi55
    TI__Genius 17370 points
    Hi XH Low,

    You mention that line 114 is EMB_Vset but our example code is line 357 and it has device id 1 instead of 0 as you have above. Please check you have latest example code here and try changing the deviceid: www.ti.com/.../EM1402EVM

    If the above does not solve this check this below:
    So the DAC output voltage never changes no matter what you change the vSet value to? This tells me that the modified code is not executing properly – please check file "emb1428.c", line 323 below and either have a watch window to check the setpoint value or force a different value and check the output voltage.

    Setpoint = (int)(Amps/2.5/(3.2/256)) + 5;

    So say for 3A, plugging into above formula would equal a setpoint of 101 so now to calculate Vout = 3.3(101/256) = 1.3V if VIO = 3.3V – please probe VIO as well to check this.

    Regards,
    Taylor
  • 0 in reply to Taylor Vogt
    Prodigy 130 points

    Hi Taylor,

    Great!!! I able to increase VSET now as per result below.

    - Set EMB_Vset(0, 3);  measured DAC output get 1.284V. (like you mentioned Vout = 3.3(101/256) = 1.3V)

    - Set EMB_Vset(0, 5);  measured DAC output get 2V.

    The code that you mentioned, i think is older version. The example code that i using is downloaded from http://www.ti.com/lit/zip/tidcbz0

    Thanks.

    Regards,

    XH Low