CCS: Solar lib SOGI PLL coefficients

Leonardo Callegaro

Other Parts Discussed in Thread: C2000WARE-DIGITALPOWER-SDK, C2000WARE

Tool/software: Code Composer Studio

Hi there

Regarding the single-phase SOGI PLL, do the coefficients of the Orthogonal Signal Generator need to be calculated at every control cycle? or are they initialised only once? Assuming that the frequency of the grid voltage is fixed to 50 Hz (except than in abnormal conditions due to faults).

Thanks in advance for your help

over 5 years ago

0 Manish Bhardwaj over 5 years ago

TI__Mastermind 43730 points

Leonardo,

For SOGI PLL you can choose yourself when to run the coefficient recalculation.

We do have a Frequency Locked Loop implementation of the PLL that will auto adjust every cycle in the c2000ware-digitalpower-sdk

but it will take more cycles

C:\ti\c2000\C2000Ware_DigitalPower_SDK_3_00_00_01\libraries\spll\include

-Manish

0 Leonardo Callegaro over 5 years ago in reply to Manish Bhardwaj

Expert 1605 points

Thank you Manish, do you think it is better to update the coefficients of the QSG at each control cycle? or is this not recommended?

0 Manish Bhardwaj over 5 years ago in reply to Leonardo Callegaro

TI__Mastermind 43730 points

Leonardo,

I do not think if you change SOGI coefficient every cycle it will work with separate routines, you need to use FLL.

SOGI can work well for the freq variation around 50Hz and 60Hz that are nominal, I did find the FLL to be useful in reducing the steady-state error and we use the steady-state error of the PLL to manage the bridge drive for more robustness.

Whether the application needs it , is hard for me to comment as we do not do all the tests needed.

-Manish

0 Leonardo Callegaro over 5 years ago in reply to Manish Bhardwaj

Expert 1605 points

Thank you Manish, your insight is very helpful

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CCS: Solar lib SOGI PLL coefficients