I finally selected the platform and CPU for the project. TI TM4C123 based CPU will be used because it has dual ADC (with quite lot of channels) with DMA capability and also two PWM modules each with 8 outputs which is exactly what I need to control two four switch buck-boost modules. Having an Cortex M4F core with support for FPU and optimized DSP libs provided by ARM helps :)
The power stage will consist of two cascaded buck-boost modules with the battery in the middle:
- First stage will be used for doing the maximum power point tracking.
- Second stage will convert the MPPT (optimal) / battery voltage to the expected output voltage.
I will build the prototype using the TI Tiva C Launchpad (EK-TM4C123GXL) that I have in my "junkbox" waiting for a project.
The high level diagram might look like this: