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Parameter StepAngleMax in RampGen Object

Aaron Rangel
Prodigy 100 points
Other Parts Discussed in Thread: TMS320F2812, CONTROLSUITE

Hi,

I'm developing a system for motor control motion with TMS320F2812 and the first step is to do the V/Hz profile.

In Texas web there are many examples to implement this function, so I decided get someone and start in this point.

I'm using the example : Field Oriented Control (FOC) of Permanent Magnet Synchronous Motor (PMSM).

 

But I don't know exactly how I've to use the parameter of RamGen Object -> StepAngleMax.

The program defines it like: StepAngleMax = _IQ(fb*T) where fb=frequency base (100Hz) and T= sampling period

My T = 1/1e3 = 0.001 and my F_ISR = 1KHz. My PWM generated is 1KHz with SVPWM technique.

 

I don't know why, if it's due to an error using this parameter definition, when the engine is started, it runs in steps (i.e. it does not turn in a continuous way, but through small steps) during a few instants an then seems to work well as the frequency grows. But if I've declared a frequency higher than 30Hz, engine works rough again and the currents are distorted. In fact, the ramp profile is not acomplished because the current decreases as frequency grows.

Well, I would like to listen opinions about that becuase I don't know what's wrong.

 

Best Regards.

Emil Zatopec.

  • 0
    Genius 5170 points

    I most likely missed your question but if your first step is to implement V/Hz then you will be better off working with an example of V/Hz implementation instead of a FOC system. Please check here http://focus.ti.com/mcu/docs/mcuorphan.tsp?contentId=51397 for a V/Hz system implemented using 281x device.

  • 0 in reply to Arefeen
    Prodigy 100 points

    Hi Mohammed Arefeen,

    Thanks for answering me, now I'm checking a project inside the url you have send me and I've a question:

    What is exactly the parameter  svgen_mf1.FreqMax = _IQ(6*BASE_FREQ*T);

    In the object I've read that is the Maximum Step Angle, but, how I know I've defined ok the parameter?

    My Base_Freq = 100 and T = 1ms and when I type it the motor stepping again.

    Any explication about what is Step angle in that system?

    Thanks again.

    Best Regards.

  • 0 in reply to Aaron Rangel
    TI__Guru** 119600 points

    Please review the documentation and system example in controlSUITE for the F28335 ACI Scalar V/Hz

    C:\ti\controlSUITE\libs\app_libs\motor_control\math_blocks\fixed_v1.1\~Docs\svgen_mf.pdf

    C:\ti\controlSUITE\development_kits\HVMotorCtrl+PfcKit_v1.6\HVACI_Scalar