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electrical brake technique of BLDC motor

vasanth kumar78
Intellectual 955 points

HI,

1.Is electrical braking required for closed loop of BLDC motor in industrial application ? ( if there is no way regenerative action in application)

2. as per my understanding, when we use position feedback sensor, PID implentation for closed loop operation of BLDC motor controlling then no required of electrical braking ( in 3 phase H- bridge inverter) & mechanical braking

please correct me if am wrong 

  • 0
    TI__Intellectual 1350 points

    Vasanth,

    Thank you for the question. I will get a response to you on Monday.

    Best,

    Johnny

  • 0
    TI__Intellectual 1350 points

    Hi Vasanth,

    It is important to note that whether or not you are using position feedback sensors, the current & speed in a motor system needs to be reduced in order for the motor to come to a stop.
    If you cannot use regenerative braking for your application, here are some other options:

    • Lowside FET brake: This method involves turning ON all low-side FETs at once to allow current to recirculate through the low-side MOSFETs. Doing this, you are effectively shorting the back emf, quickly lowering the motor speed and slowly dissipating the current. This method puts a particular strain on your lowside FETs since the motor power gets dissipated there.
    • Highside FET brake: This method involves turning ON all high-side FETs at once, having the same effect as the low-side FET braking. This method strains the high-side MOSFETs.
    • FET alternation braking: An alternation between the two above listed options (high-side brake and low-side brake), in order to prevent strain on a particular set of FETs.
    • Coasting: This form of braking involves switching all mosfets into Hi-Z state, and allowing the motor to coast to a stop (this coasting can generate a significant amount of voltage). This form decays the motor current quickly, but is not always the best option, depending upon your application and power supply voltage margin. You might also be against this option for your application, as it is similar to regenerative braking.
    • Resistive braking: The current decays through an external resistor + MOSFET in parallel with the motor and FETs (from VDRAIN to GND). This resistor should be turned ON only when the motor needs to brake. The aspects of this resistor must be precisely calculated based upon motor system properties.

    Some combination of the above methods can be used. hope this information helps

    Best,

    Johnny

  • 0 in reply to Johnny Vallespir
    Intellectual 955 points

    Hi,

    Thank you for your reply,

    is above methods applicable for BLDC motor Driver (H bridge) ?. If u have any document regarding implemented above braking methods on BLDC motor (H-bridge) Please share

  • 0 in reply to vasanth kumar78
    TI__Intellectual 1350 points

    Vasanth,

    Yes, The above methods are applicable and are used for BLDC motor drivers with H-bridges. We do not currently have any content on implementing these braking methods.

    The following post is relevant when considering the effect of supply pumping due to the different methods of braking: https://e2e.ti.com/blogs_/b/industrial_strength/posts/art-of-stopping-the-motor-vm-pumping

    best,

    Johnny

  • 0 in reply to Johnny Vallespir
    Intellectual 955 points

    Hi,

    Than you very much for sharing information

  • 0 in reply to vasanth kumar78
    TI__Mastermind 21805 points

    Hi Vasanth,

    Let me know if you need anything else. Otherwise I will close the thread.

    Thanks,

    Matt

  • 0 in reply to Matt Hein
    TI__Mastermind 21805 points

    Hi Vasanth,

    I will go ahead and close this thread. Feel free to ask a new question on the forum!

    You can click the "Ask a related question" button at the top right of the screen.

    Thanks,

    Matt