The Peak Power Tracking Project

This the latest prototype for my Peak Power Tracker. I've written an article for Home Power Magazine that should come out some time in the summer of 2004. I'll post it on my articles page when it's published. In the mean time you can read about the history of the project with Steve Roberts below. Also here are the project files with all the details including schematics and software listing.

Schematic - schematic of Peak Power Tracker in pdf format.

Software - C file listing of Peak Power Tracker software.

Circuit description - MS Word file description of the hardware.

Software description - MS Word file of description of the software.

Output Graph - Graph showing actual power output from my home solar system with PPT off and PPT on in pdf format.

History of the Peak Power Tracker Project

Two years ago I ran across Steve Robert's great web site. I was fascinated by Steve's adventures and intrigued by their technical nature. I was especially intrigued by Steve's offer of a "geek's vacation" to anyone who wanted to visit him and work on his Microship project. I took him up on his offer and stayed with Steve and wife Lisa at their house on Camano Island. Steve and Lisa have built a great shop that is just a short walk through the woods from their house where the work on the Microships takes place.

The Microship project is two small boats that Steve, Lisa, Bob Stuart and a multitude of volunteers are building. Next year Steve and Lisa will start at the headwaters of the Missouri River for a travel adventure to destinations unspecified. To propel them the boats have sails, a pedal power system and a solar electric drive. I volunteered to work on the solar electric drive system and my main task has been the design of a multi channel peak power tracking system for the solar panels. A 12 volt solar panel actually generates its peak power or wattage at about 16 volts. When it is connected directly to a 12 volt battery the battery draws the solar panel voltage down to arount 12 or 13 volts. The solar panel then is not operating at its peak efficiency. The peak power track is basically a DC/DC converter that converts the 16 volts of solar panel down to the 12 volts of the battery system. A microprocessor continuously monitors the power the solar panel is producing and adjusts the DC/DC converter to get the maximum power out of the system.

I'd like to add more technical details about my peak power tracking system to this page in the future but for now I just have images of the three generations of prototypes that I've built.

The first breadboard prototype. If you click on the thumbnail for a larger image you can see the scorch marks on breadboard from an diode failure.

The second prototype built on a soldered prototype board. You can see the heat sink for the MOSFET switch and the flyback diode. The inductor is offboard to facillitate testing of different values and cores. The flat ribbon cable runs to the microprocessor development system.

The third prototype is built with a custom designed printed circuit board and has 4 channels of peak power tracking. The 4 solar panels are connected to the terminals at the front of the board. You can see the 4 heatsinks for the MOSFETs and the 4 inductors in the center of the board. The connector on the right side of the board goes to the battery in the system and a serial communications port is on the left side. The ribbon cable on the back of the board is connected to the microprocessor development system.

The Microship in an state of dissasembly.