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TMS320F28034: Vout alway hit OVP thresh after implement INCC mppt algorithm

Jack Tan80
Mastermind 7150 points
Part Number: TMS320F28034
Other Parts Discussed in Thread: CONTROLSUITE, SFRA

Dear c2000 expert,

I'm using the INCC mppt algorithm code from controlsuite for my power, here is the diagram what I'm using, Ipv is the boost average current, Iboostsw is used for current loop feedback. And I used a analog comparator configured as CBC for OVP purpose. 

But the vout is ways hit the OVP thresh even I increase the load and vin drops, can you please help share your comment on this?

And here is mppt variable initialize value. 

boost_vars.mppt_incc.IpvH = _IQ(0.0001);
boost_vars.mppt_incc.IpvL = _IQ(-0.0001);
boost_vars.mppt_incc.VpvH = _IQ(0.0001);
boost_vars.mppt_incc.VpvL = _IQ(-0.0001);
boost_vars.mppt_incc.MaxVolt = MAX_VIN_Q24; //300V
boost_vars.mppt_incc.MinVolt = _IQ(0.0);
boost_vars.mppt_incc.Stepsize = _IQ(0.001);
boost_vars.mppt_incc.StepFirst = _IQ(0.05);
boost_vars.mppt_incc.mppt_first=1;
boost_vars.mppt_incc.mppt_enable=0;
boost_vars.mppt_incc.Vpv_fault = 0;
boost_vars.mppt_incc.slewrate = 0;

Regards,

Jack

  • 0
    TI__Mastermind 43730 points
    Jack,

    You need to break down the issue to one problem, it is unclear to me from your post whether you have a power stage issue, software issue, peripheral configuration issue etc.

    You might want to run your system in open loop first and see if the power stage is fine,

    next you can include closed loop control and check,

    then you can add MPPT and see it is not an issue at startup of the MPPT code etc..
  • 0 in reply to Manish Bhardwaj
    Mastermind 7150 points

    Manish,

    Thanks for your comments. 

    I have verified my hardware by using average current mode control with DC source input, there is no problem. So I think my hardware should be good.

    Then after checking my code with TI demo carefully, I found that I used vout signal for voltage loop's feedback instead of input volt signal. This is the root cause of making VOUT always hit OVP. 

    But the input current decreased to 0 after power stage startup after fixed this bug. Then I turned voltage loop coefficient by increasing input voltage loop's bandwidth, I have got a good improvement. But it is still not the best one, because it doesn't output a max power in boost stage. It seems that the coefficients will affect the performance. So can you please share some docs or comment on how to identify voltage/current loop's coefficient? And how to set the stepsize for MPPT algorithm?

    Regards,

    Jack 

  • 0 in reply to Jack Tan80
    TI__Mastermind 43730 points
    Jack,

    You can refer to our SFRA library and compensation designer to tune coeff

    www.youtube.com/watch