Is it possible to Use the MPP-Ref Pin of the SPV1050, to implement an own MPPT?

SNadi.1 · ‎2020-04-17

Hi,

I am workung currently on an energy harvesting project. I try to use the spv1050 IC to extract my energy from a electromagnetic-vibration harvester. I know that this IC is for other types of EH's, but still it is the only IC, which meets my specs as close as possible.

I try to controll the IC with a micro controller, because the MPPT from this IC is not usefull for my application.

Is it possible with deactivating the MPPT of the board and Using the MPP-Ref Pin, to adjust your Ref-Voltage and let the IC regulate to that reference? So more easily asked: If I change my Ref-Voltage, does the "input-impedance" of the IC change too? Wich would mean that the input voltage also changes?

Thank you very much for your help.

Best Regards

Sohail

PMcDo.1 · ‎2021-08-21

Hi Sohail,

Did you ever try this and get it to work? I was thinking of doing this exact thing (deactivate MPP, and drive reference voltage with a DAC). The datasheet wording is a bit confusing, but I was imagining adjusting the MPP_REF would allow the switching frequency/duty to be adjusted which would change the input impedance.

Cheers,

Parker

SNadi.1 · ‎2021-08-22

Hi Parker,

Yes I tried it. It works and with adjusting the MPP-REF one can adjust the freq/duty. This allows you to use different "self-made" MPP-trackings. For me the type of MPPT (I think this method is called "fractional voltage tracking") was just not suitable.

For adjusting the MPP-REF, you can use any type of DAC.

I hope this helps you.

Cheers,

Sohail

PMcDo.1 · ‎2021-08-22

Awesome, thanks for the reply! That's actually a really nice feature as the hard coded MPP algorithm is much too slow for my application (mobile robotic platform) where the energy source can change quickly based on environmental conditions. Did you ever use the LDOs for powering other devices? It is unclear to me if the LDOs stay powered when the energy harvested source goes away...according to the datasheet the LDOs are powered off the STORE rail, which is connected to the battery directly when VUVP < STORE < VEOC.

Thanks,

Parker

SNadi.1 · ‎2021-08-23

Yea dependent of the application this algorithm can be slow.

Yes you can do it. As long as you make sure, that device is consuming very low amount of power, and never more than the source delivers when battery disconnected, you can use it. But in the worst case, you can supply them with the battery ....

Thanks

Sohail