Probably, the 3V DC-DC converters for MPPT function are unavailable; most MPPTs are constructed for handling battery control function too. Therefore, their voltage ratings are multiple of 12. Try to careful search amazon, and alibaba you may find the suitable one.

The LTC3105 is a boost converter that can start up at the exceedingly low voltage of 0.25V. This makes the LTC3105 particularly well suited for boosting the output voltage of a “1S” solar panel (i.e. a solar panel whose output voltage is that of a single photovoltaic cell, even if the panel has many photovoltaic cells in parallel)

Pl. check:

LTC3105 - 400mA Step-Up DC/DC Converter with Maximum Power Point Control

http://www.linear.com/product/LTC3105

The other one you can have a look is:

LTC3129 Synchronous Buck-Boost DC/DC Converter. It allow predictable regulator turn-on and a maximum power point control (MPPC) capability that ensures maximum power extraction from non-ideal power sources such as photovoltaic panels.

Wide VIN Range: 2.42V to 15V, 1.92V to 15V

Wide VOUT Range: 1.4V to 15.75V

It seems that the LTC3105 converter recommended by Asma is a perfect choice. It is also cheap too.

That is very kind of you.

Have you come across any ready evaluation board that i can just plug and play?

Thanks

It will be better if you prefer ultra low voltage DC/DC converter employed with programmable MPPT along with battery management provided by texas , rate must be affordable too