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TMS320F28379S: Recommendations

Jon Tuna
Intellectual 1275 points
Part Number: TMS320F28379S
Other Parts Discussed in Thread: C2000WARE, DESIGNDRIVE, SFRA, TMDXIDDK379D

Hello, 

Could you share your recommendations please?

From Customer:

We’ve designed our own 2 level topology three phase Inverter.

  • Carrier frequency is 533Hz.
  • DC Link Voltage is 1400VDC

 

The Inverter is driving a 3 phase AC induction Motors for propulsion with the following Spec:

 

GE GEB13A/B

  • Peak power: 1200 HP (858kW)
  • Peak voltage :1000Vrms
  • Peak speed: 3920 RPM (196 Hz)*
  • Peak Current: 1200 Arms per phase
  • Number of poles: 6 *
  • Carrier switching frequency: 533 Hz
  • Stator resistance: 2.275 to 2.554 Ω*

 

In addition to the 3 phase current 4-20mA transducers we have a 3 AC Voltage sensors ground speed radar as well as motor speed probes on the bull gear.

Note the Voltage sensors are for additional data and protection and not used for any FOC control algorithms.

 

Our current custom board is designed with a F28379S TI processor.

 

The question we’d like to ask is where to go and/or what are our options for a starting code base from the TI projects.

What our are options with F28379S processor?

 

From my preliminary research it seems like there are three main options for control from the C2000Ware.

 

  • InstaSPIN-FOC, could this work despite not having a FAST supported MCU.

Can/should we still use portions of the control approach with the F28379S?

 

  • InstaSPIN-MOTION, seems like FAST MCU support is optional in this method which could allow us to use this with the F28379?

SpinTAC motion control suite: would this be recommended for propulsion motors?

 

  • TI MotorControl SDK 4.02.00.00 recommends DesignDRIVE solution for the 28379.

Seems like this is the option we have to go with but would appreciate advise and/or feedback.

 

Focusing on DesignDrive in the event that InstaSPIN-FOC and Motion are not suitable for the 28379 processor:

  • FOC: Uses FCL and SFRA to keep control loops under 2uS.  With our carrier frequency being 533Hz instead of the 10kHz in the example achieving 1uS loop time far exceeds our needs.
  • Project example is boostxl_3phganinv.  This example is for dual motor control.  Seems like it could be modified to just single motor control.

While the example is for a PMSM (permanent Magnet Synchronous Motor) the documentation calls out that the approach can be for asynchronous motors as well by adjusting the flux reference current to greater than 0.

  • There’s a second recommended project Tmdxiddk379D. Seems to be very similar control approach to the boostxl_3phganinv but for a different development kit. 

 

Seems like are quite a few avenue’s to explorer from the TI code base. In the spirit of saving resources diving into each control option in your opinions what are the best and most straightforward path with the F28379 to getting an FOC/DTC control approach rotating a propulsion motor?

FOC seems like the option to get rotating the motor in the shortest time after which think we will eventually move to the DTC approach.

 

Lastly,

In your opinion do the pros outweigh the cons of moving to a FAST equipped MCU for FOC/DTC control in future revisions of the board?

 

Thanks

Jon 

  • 0
    TI__Guru** 112660 points
    Jon Tuna said:
    What our are options with F28379S processor?

    All of the latest C2000 MCUs can be used for this including F28379S. The user can select the right one per the GPIO, ADC and CPU frequency required by their system. Yes, F2837x could be a good choice.

    Jon Tuna said:
    • InstaSPIN-FOC, could this work despite not having a FAST supported MCU.

    Can/should we still use portions of the control approach with the F28379S?

    What type of the motor the customer is using? ACIM or PMSM?

    Jon Tuna said:
    SpinTAC motion control suite: would this be recommended for propulsion motors?

    What application it is? Does the application need position control? The F2837x can't support SpinTAC.

    Jon Tuna said:
    Seems like this is the option we have to go with but would appreciate advise and/or feedback.

    Please provide more details about the motor and the application.

    Jon Tuna said:
    In the spirit of saving resources diving into each control option in your opinions what are the best and most straightforward path with the F28379 to getting an FOC/DTC control approach rotating a propulsion motor?
    Jon Tuna said:
    In your opinion do the pros outweigh the cons of moving to a FAST equipped MCU for FOC/DTC control in future revisions of the board?

    As mentioned above. The user may select the right control algorithm according to their applications. TI only has FOC reference., but customer can develop their own algorithm using FOC or DTC on C2000 MCUs including F2837x.

  • 0 in reply to Yanming Luo
    TI__Intellectual 1275 points

    Hello Yanming, 

    Customer has designed their own 2 level topology three phase Inverter.

    • Carrier frequency is 533Hz.
    • DC Link Voltage is 1400VDC

     

    The Inverter is driving a 3 phase AC induction Motors for propulsion with the following Spec:

     

    GE GEB13A/B

    • Peak power: 1200 HP (858kW)
    • Peak voltage :1000Vrms
    • Peak speed: 3920 RPM (196 Hz)*
    • Peak Current: 1200 Arms per phase
    • Number of poles: 6 *
    • Carrier switching frequency: 533 Hz
    • Stator resistance: 2.275 to 2.554 Ω*

    Thanks

    Jon 

  • 0 in reply to Jon Tuna
    TI__Guru** 112660 points

    Do they want to run the motor with position sensor or sensorless? And only need speed control or torque control?

    Seems like the typical FOC algorithm is difficult to meet their requirements since the motor needs to run a high frequency (200Hz) with such low carrier switching frequency (533 Hz).

    They may have to design their own control algorithm with C2000 controllers like F2837x.

  • 0 in reply to Yanming Luo
    TI__Intellectual 1275 points

    Hello Yanming, 

    I am reopening this conversation. There are a few more follow up questions. 

    You mentioned high frequency (200Hz) did you mean 200kHz?

    If so then our carrier frequency is comparatively low.  Which is plus on the firmware side given the comparatively long time we have to run our control loops.

    Can you elaborate further on why the typical FOC algorithm would be more difficult with us running a low carrier frequency?

     

    Could the customer still start from one of the FOC algorithms offered by TI and adjust the parameters and control to achieve what we need on our carrier frequency or is that not possible and starting from scratch is the best path forward?

    Thanks

    Jon 

  • 0 in reply to Jon Tuna
    TI__Guru** 112660 points
    Jon Tuna said:
    You mentioned high frequency (200Hz) did you mean 200kHz?

    200Hz is the motor frequency. It is still difficult to run the motor to 200Hz with such low switching frequency (PWM). C2000 can be used for this application, but we don't have such reference design with FOC to meet this requirement. Customer has to find and design the algorithm with C2000 by themself. 

    Jon Tuna said:
    Can you elaborate further on why the typical FOC algorithm would be more difficult with us running a low carrier frequency?

    The switching frequency (PWM) must be far higher than the maximum electrical frequency of the motor, at least 24~36 times to achieve a better modulation resolution.

    Jon Tuna said:
    Could the customer still start from one of the FOC algorithms offered by TI and adjust the parameters and control to achieve what we need on our carrier frequency or is that not possible and starting from scratch is the best path forward?

    The customer can use the example FOC algorithm in C2000 motor control SDK, but they may need to make some improvement or changes for this high power motor. We didn't test the examples in such condition as customer wants, and didn't do any research on this as well since the industry customer can design their own algorithm with C2000 for such applications.

  • 0 in reply to Yanming Luo
    TI__Intellectual 1275 points

    Hi Yanming, 

    Thank you for your response. 

    Regarding TMS320F28379SPTPT suitability, customer simply needs to add the FOC library support vs running it from one of the ROM equipped processors, is that correct?

    Thanks

    Jon 

  • 0 in reply to Jon Tuna
    TI__Guru** 112660 points

    Correct. Only InstaSPIN-FOC runs the FAST estimator from ROM on F2802xF, and F2806xF/M. The TMS320F28379SPTPT doesn't have such ROM with FOC library, the customer needs to use the static software library or open source for running FOC on TMS320F28379SPTPT.