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DRV8301-69M-KIT: Testbench...or accuracy of Torque-Control

Sebo
Intellectual 385 points
Part Number: DRV8301-69M-KIT
Other Parts Discussed in Thread: INSTASPIN-BLDC, CONTROLSUITE

Hi,

I am developing a Controller for a BLDC-Motor using Instaspin FOC. This system needs to be tested. Below I am just talking about the Motor and Control of the Testbench. NOT the controller I am working on.

For this development I need a Testbench. This Testbench doesn't need to provide a super high accuracy as my budget is not pretty high. My range goes is 0-500W and 0-20Nm. If my erroer is +- 0.5Nm i really don't care.

My question is: As Testbench (or dyno) I want to use DRV8301-69M-KIT and a BLDC Motor providing the range i need to brake and accelerate the "Motor Under Test".  If I use DRV8301-69M-KIT and the given development software it should be possible to let the DRV8301-69M-KIT detect the BLDC-Parameters and drive a Torque or Speed Control.  But my question now is. How Accurate is the Measurement of Torque and Speed the Instaspin Technologie gets from FLUX and BEMF measurement?  Do I need a Motor with Hall and Ecoder or would this work sensorless as well?

Would you realize a cheapt Testbench in this way or does anybody have a better Idea? I would be very thankful!

kind Regards

Sebastian

  • 0
    TI__Guru** 116090 points
    There is about 1~5% accuracy which depends on load and speed range, much higher accuracy for rated speed with half rated load, and much lower for low speed without any load on motor shaft. Encoder sensored is much better than sensorless especially in low speed. InstaSPIN-FOC should be good for your application if you don't need very low speed.
  • 0 in reply to Yanming Luo
    Intellectual 385 points
    Hey thank you very much for this answer!
    Now i found this evalkit: DRV8301-HC-C2-KIT As it can drive up to 82.5A, it would be much better for my use.
    AS i read now it uses Instaspin-BLDC .. Is there a Torque Control and how accuracy is is?
    I thoudh Instaspin-BLDC is kind of "old" and not used anymore?
    why isnt there a Kit providing 82.5A with a 69M on it?
  • 0 in reply to Sebo
    Intellectual 655 points
    The term BLDC is used for a specific type of control and a specific motor type, as well as a generic term for a permanent magnet motor. There is some confusion.

    InstaSPIN-FOC needs phase current and voltage measurements, and a 2802x, 5x, or 6x chip. As long as the DRV8301-HC-C2-KIT has those, you should be able to put a '69 controlCard in there and use InstaSPIN-FOC.
    "Torque control" just means setting a torque generating current setpoint (IqRef). FAST can report the generated torque, and in my experience this is precise enough to leave out any torque meter from your testbench. As Yanming says, near zero speed is where things get tricky. Since the measured phase voltage change is nearing zero, this tends to disappear in the noise of the system. As long as you are okay with measuring torque at some speed (say 3-4 Hz electrical frequency), I would make do without a physical torque meter.
  • 0 in reply to Sebo
    TI__Genius 17175 points
    The DRV8301-HC-C2-KIT is compatible with the F28069M Control Card. You should be able to test this MCU on such an EVM up to the rated limits of the hardware package.

    InstaSPIN-BLDC is an open-source software available through ControlSUITE that was developed prior to InstaSPIN-FOC/MOTION. These labs are supported by our team, but no new open-source development is planned at this time.

    Sean