Phase Locked Loop (PLL) for grid connected output

A generic PLL can be found online ...Google will offer a number of examples ... however, the IP is in making the PLL robust enough for real world application. I doubt you will find those real-world PLL implementations as free example or download. By the way, are you looking for a three phase or single phase application?

Felix,

I have an implementation of SPLL that i am happy to share, you would need to send me a message with your affiliation through the community,

You can friend me to send me an email, 

regards

Manish Bhardwaj

Hello Manish,

I need such an implementation example too.

I am working on a 3-phase grid connected solar inverter project and I need to syncronise the inverter output to the grid. I have tried simply zero crossing feedback from grid for syncronisation, but THD is too high in this case.

I send you a friend request. Could you share your SPLL implementation with me as well.

Regards,

Kerem

Hello Kerem .. Zero crossing detection method is simple but may not be sufficient in many applications. One possible solution is to use Clark /Park transformations in addition zero crossing information to have a more robust implementation. You will also have to watch for line noise, line voltage unbalance and faults.

 I am also interested to know more about TI implementation ... please post the link, if available, for download.

Hello  Manish,

I am also have this kind of problems in the implemention of SPLL, could you share you PLL implement (single phase)with me as well.

Thanks!

Danny

Dear all,

The PLL method is now available in ControlSUITE both in fixed and IQ format,

Please check,

ControlSUITE\libs\app_libs\solar\

Regards

Manish Bhardwaj

Can you tell me how to determine the coefficients for 2P2Z Notch Filter at different sample rate, say 10e-6s. Thanks.

Tony Jiang

You can use band stop filter to closely approximate the notch

for example in Matlab coefficients can be got from

[B,A]=butter(1,[95*2/10000 105*2/10000],'stop')

Regards

Manish Bhardwaj

Manish,

As per the document (pdf) in ControlSUITE\libs\app_libs\solar\.. It says the PI takes care of the system dynamics. And no more we have to take concentrate on the  filtering capabilities of PI. But in the Code (provided as Header file), the PLL is created with the PI, considering as a Low pass filter... and moreover a notch filter is also use.. Could please clarify me the use of two filters (LPF and Notch filters) in the code.

And also let me know, whether this PLL work for a polluted grid. Grid containing Third, fifth and some EMI etc...)

Thanks in Advance.

Angamuthu,

Classical PLL consists of PD, LF (PI) , VCO. If you look at the small signal model of a PLL the BW of the PLL is determied by how you tune the LF(PI). The small signal model assumes the 2w frequency is high and will be cancelled out by the low pass characteristics of the LF(which is tuned for the BW and not to filter out the 2w).

For grid tied applications the 2w is low enough that the low pass characteristics of the system cannot be banked upon alone, Hence a notch filter was added to  cancel the 2w. LPF -. loop filter in some cases , sorry for the confusion. 

The PLL is resilient to polluted grid and harmonics,

What are your affiliations?

Regards

Manish Bhardwaj

hi  Manish ,

      From  Solar HV DC-AC Kit User Guide_Rev1.0.pdf ，It seems the project has an anti-islanding function,But I can't find related code in .

...:\TI\controlSUITE\development_kits\HV_SOLAR_DC_AC_v1.0\SolarHv_DCAC_PiccoloB_Rev_02 

Do you know when the related code will be released?    Thanks!

Hello Manish,

I have read some post you have done, seems that you have work a lot with SPLL.h, maybe you can help me working on my code.

I need to create another theta that will take an user input to change the phase (in degrees) of my system. Do you have any hints for me??

WHat is the application you are trying to write the PLL for? single phase? 3 phase... grid connected?

I am using a single phase. I  have actually two solar kits, one of the is the grid simulation which will be feeding into the other's battery.  Anyhow, that will be the long run, now I am just working on the PLL lock an input phase .

I am working on the float file.