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TIDM-02010: Causing the output IPM fault

MOHD AKBAR
Prodigy 10 points

Part Number: TIDM-02010

Hi,

We are working on TIDM-02010 model. Here at output of microcontroller, we are getting PWM's (with glitches), at output when there is no load we are able to change the frequency of PWM duty cycle to 80Hz(Max we have checked). But, when the compressor motor is connected we are not able to run compressor more than 25Hz PWM Duty cycle. When we are increasing the Frequency of varying the Duty cycle more than 25Hz, it is generating the fault at IPM. The Bootstrap capacitors we will be using are 10uF/63 Electrolytic capacitor and 0.1uf Ceremic capacitor. I have not mounted the Bootsrap diode as datasheet mentioned that it has inbuilt bootrap diode. Help me if i am making any mistake.What could be the problem i am making in it.

 

 

  • 0
    TI__Mastermind 22021 points

    Hi Mohd,

    Can you help clarify your question? Are you working directly with TIDM-02010 hardware? 80 Hz and 25 Hz are VERY slow for the compressor, I was expecting something in the range of 6kHz. What IPM fault are you seeing? IPM may have protection feature to prevent too-high duty cycle input

    Regards,

    Peter

  • 0
    Prodigy 10 points

    Hi Peter,

    Yes, I am working with same TIDM-02010 model. The frequency I have mentioned is regarding the PWM Duty cycle varying frequency. The PWM frequency is 6KHz. The fault is neither overcurrent fault ( as voltage at CSC pin is 0.22V). The only thing I have found is Glitches is observed when running motor. Will it cause any protection triggered to IPM.

  • 0 in reply to MOHD AKBAR
    TI__Mastermind 22021 points

    Hi Mohd,

    I understand now what you mean. Please refer to the device technical reference manual regarding the EPWM module. Depending on the EPWM clock frequency, you have a certain limitation to the accuracy of the PWM duty that is limited by the EPWM clock frequency. This is defined as the resolution of the PWM and is dependent on what your intended switching frequency is. We don't typically use high-resolution PWM (HRPWM) for motor control applications as it's not typically necessary. But if you need the ability to leverage the high-resolution period, then you can reconfigure the software to leverage HRPWM. 

    For glitches, are you referring to motor knocking or something else? This may require you to adjust the control loop parameters and better tune it for your specific motor. You can run the motor ID instaspin routine to identify the correct parameters

    Regards,

    Peter

  • 0 in reply to Peter Luong
    Prodigy 10 points

    Hi Peter,

    Problem is still not resolved. Looks like PWM's are okay. And those are not High Resolution PWM's. We are not using PFC Current sensing as we are trying to run at V/F open loop method. What can be the any other reason for it?

  • 0 in reply to MOHD AKBAR
    TI__Mastermind 22021 points

    Hi Mohd,

    Can you provide pictures of the glitches you are referring to? It is still not clear what issue you are currently seeing

    Regards,

    Peter

  • 0 in reply to Peter Luong
    Prodigy 10 points

    15V supply when compressor is running in Sensorless FOC 

    Hi Peter,

    The problem with running in V/F mode is now solved. The noise/glitches on the CSC pin were causing false overcurrent triggers. After disconnecting (floating) the CSC pin, we were able to run the compressor successfully in V/F mode.

    However, when we tried to run the motor using the Sensorless FOC method, we observed glitches on all supply rails (15V, 3.3V, and 5V). I have attached an image showing the noise on the 15V VCC pin of the IPM.

    Due to this noise, the MCU is resetting (coming out of flash), and the motor fails to rotate.

  • 0 in reply to MOHD AKBAR
    TI__Mastermind 22021 points

    Hi Mohd,

    Have you properly configured the motor specs for the FAST/eSMO algorithms? If these motor specs are not properly updated, you may see issues

    Additionally, is the MCU actually getting reset or is it only the JTAG is disconnecting? The JTAG is sensitive to high voltage so if you have opportunity to use our isolated XDS, that will be more robust and immune to the high voltage noise

    Regards,

    Peter