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TMS320F28069F: Phase current sensing configuration (low-side or high-side)

Geon Kim
Expert 1070 points
Part Number: TMS320F28069F
Other Parts Discussed in Thread: TMDSHVMTRINSPIN,

Hello,

We purchased the TMDSHVMTRINSPIN development kit.

Our target application is the sensorless Field Oriented Control of ACI motor.

We are currently designing our prototype for an ACIM inverter/controller by using the TMS320F28069F DSP.

My question is on the configuration for the phase current sensing.

I have found out that the TMDSHVMTRINSPIN development kit uses the low-side three shunt sensing configuration.

Meanwhile we have found out that the phase current may be able to be measured by using the isolated hall sensor IC at the high side.

Is there any merit if I use the isolated hall sensor ICs at the high side to measure the phase currents for our prototype design which employs the TMS320F28069F DSP?

Otherwise does TI recommend to use the low-side three shunt sensing configuration as in the TMDSHVMTRINSPIN development kit.

Of course I know well that the material cost would go up if I use the isolated hall sensor ICs at the high side to measure the phase currents for our prototype design.

Thank you for your guidance.

With regards,

G. Kim

  • 0
    TI__Guru** 115470 points
    Usually, the current shunt resistor on low-side is used for some low current, cost sensitive application, it's just an option of sensing current in motor control. You might use isolation hall sensor as you mentioned, that's easier to sample a good current signal, you just need to put the sensor on the motor phase line even you don't need to change any control code.
  • 0 in reply to Yanming Luo
    Expert 1070 points

    Dear Luo,

    Thank you for your review.

    It is described in detail in Chapter 17 of InstaSPIN-FOC and InstaSPIN-MOTION User's Guide that the three shunt current measurement is the ideal method for an application of InstaSPIN.

    The Shunt Current Measurements of Chapter 17 is associated with the low-side shunt current sensing.

    Would it be the same story even though the high-side shunt current sensing configuration using the isolation hall sensors is employed?

    Is the three shunt current measurement the ideal method for an application of InstaSPIN even though the high-side shunt current sensing configuration using three isolation hall sensors is employed?

    Otherwise may the two shunt current measurement is enough for an application of InstaSPIN when the high-side shunt current sensing configuration using two isolation hall sensors is employed?

    Thank you for your guidance.

    With regards,

    G. Kim

  • 0 in reply to Geon Kim
    TI__Guru** 115470 points
    Right. That's ok for any FOC includes instaSPIN-FOC also if you place the current sensor on the motor phase lines ( as you mean high-side shunt current sensing), and the current sampling can be triggered at any time.
  • 0 in reply to Yanming Luo
    Expert 1070 points

    Dear Luo,

    Thank you for your review.

    Let me make this issue resolved clearly with reference to your reply.

    I would conclude as follows:

    Even though the high-side shunt current sensing configuration using the isolation hall sensors is employed, the three shunt current measurement is the ideal method for an application of InstaSPIN-FOC.

    Therefore the three shunt current measurement, instead of the two shunt current measurement, should be employed irrespective of whether the high-side or low-side shunt current sensing configuration is implemented.

    If my conclusion stated above is not what you mean, please let me know.

    Thank you for your guidance.

    With regards,

    G. Kim

  • 0 in reply to Geon Kim
    TI__Guru** 115470 points

    You can use two or three shunt current for both low-side and high-side, but two-shunts is enough for any cases if you are using inline/high-side current sensors.

    Btw, the following application notes maybe help you to understand the current sensing mode.
    www.ti.com/.../sboa172.pdf
    www.ti.com/.../tiducy7.pdf