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TIDA-00281: The gate driver chip UCC27201A-Q1 & Mosfets gets damaged while trying to run a 300W BLDC motor (60V - 5Amp rated)

Part Number: TIDA-00281

Hi,

We have used the TIDA-00281 design to run a 300W BLDC motor. The motor runs properly at very low speed but if we increase speed somewhat then it starts experiencing jerks. If we increase speed further then gate driver chip gets damaged on phase A. The pin2 (HB) and pin4 (HS) gets short with the ground. The high and low side mosfets on phase A also gets damaged, gate gets short with Drain and source. We have noticed this damage twice on phase A.

We cannot identify what's going wrong. We checked six step wave forms in the CRO and observed that when the complementary PWM given on high and low side of any phase ends, in the last cycle both the signals gets high. Please find attached wave forms for the open loop six step PWM given to gate driver chip. The makers 0 & 1 are phase A HI and LI, similarly 2 & 3 are for phase B HI and LI and 4 & 5 are phase C HI and LI. I have highlighted the waveform part in image tek00004 and tek00006.

Can you also confirm if the PWM we are giving are proper.

Ish.zip

  • Hi IP,

    I forwarded your question to the author of the reference design. Please stay tuned.

    Best regards, Jiri

  • IP,

    The attached oscilloscope/logic analyzer traces don't show both LI and HI in a simultaneous high state.  The image in TEK00006.png shows the last yellow signal (HI?) going high just as the blue signal (LI?) going low.  If this condition is causing the problem, you might try increasing the dead time between HI/LI transitions.  In TEK00003.png, it looks like the dead time is about 2 microseconds.  It also looks like your PWM frequency is about 20 kHz (50 us period).

    If your drive A FETs are being damaged, have you looked to see what is different about your phase A drive circuit, compared to phase B and phase C?

  • Hello Clark,

    Upon increasing the dead band the condition gets worse. Both signals goes high at the same time at the end of PWM cycle.

    Can you confirm from the previously sent images that the Six step wave forms we are providing are correct to drive a BLDC ?
    Is the 20kHz PWM frequency correct ?

    Also the drive circuits for all the three phases are same as in TIDA-00281.

    Regards,
    IP

  • Hi Clark,

    We did some changes in the PWM architecture of the DSP and the issue got resolved. We also placed the current sense and limit logic to prevent mosfet damage.

    The problem is resolved now. The motor runs fine.

    Thanks for your support..!!!