Maximum power point tracker

solar panel maximum power point tracker
MPPT Solar and Wind Power Boost Charge Controller

Free Charge Controller project
The goal of the open source Free Charge Controller project is to design a charge controller with maximum power point tracking (MPPT). Maximum power point tracking allows a solar panel, wind turbine, etc to achieve maximum efficiency and deliver maximum power to a load. In this case, a load can be a battery, inverter, or the grid. This is both an open source hardware and an open source software project. All documents and files are released for free under the terms of the Creative Commons Attribution-Share Alike license. With enough help, it is hoped that future versions will support different battery voltages, off-grid and grid-tied systems, as well as other power sources such as wind turbines, micro-hydro turbines, etc. If you'd like to help, please join our developer forum.

wind turbine maximum power point tracker
I'm designing a maximum power point tracker (MPPT) specifically optimized for wind turbines.

Currently available off-the-shelf MPPTs work fine in the application they were designed for. (See wikipedia: maximum power point tracker for details). However, apparently they won't work with wind turbines. When they pull the maximum instantaneous power from a spinning turbine, the turbine blades go slower and slower until it stops, at which point you're getting zero power out.

The wind turbine maximum power point tracker I'm designing will extract more energy over the course of a day than those MPPTs. Instead of pulling the current that maximizes instantaneous power out, it will pull somewhat less current in order to keep the blades spinning at the optimum speed. The optimum speed will change over the course of the day as the wind speed changes.

--DavidCary 08:14, 26 September 2008 (PDT)

I've considered 2 possible strategies:

(a) keep the blades spinning at the optimum speed, the speed that gives the maximum power out at the current wind conditions. The wind turbine acts as a base load power plant, in the sense that the amount of power it supplies is independent of the load.

When using this strategy "a" with off-grid systems tied to a battery, when some device (say, a cordless drill) needs a quick burst of energy -- more power than the wind turbine is currently generating -- supply that energy from the batteries.

(b) When there is low load, let the blades spin up slightly faster than the optimum speed. When some device (say, a cordless drill) needs a quick burst of energy -- more power than the wind turbine is currently generating -- supply that energy from by pulling *more* power from the wind turbine, temporarily slowing it down. The wind turbine acts as a peaking power plant.

This strategy "b" uses the spinning blades as a form of flywheel energy storage.

Which strategy is better for battery-less grid-tied wind turbines? Which strategy is better for off-grid systems with battery backup? --DavidCary 11:33, 27 September 2008 (PDT)

Online Resources

 * Solar Energy
 * How to Build Your Own SD-100 MPPT - Schematic & Instructions on how to build your own
 * Red Rock Energy: Maximum Power Point Trackers
 * LT3652: the "Linear Technology LT3652 - Power Tracking 2A Battery Charger for Solar Power" contains most of the electronics required for MPPT up to 2 A in a single IC (4.95V to 32V). With the LT3652, the installer hard-wires some fixed approximation of the maximum power voltage of the solar panels Vmp at 25'C, and (optionally) a temperature sensor on the solar panel used to give some fixed linear approximation of the change in Vmp with temperature. via.
 * Chris: "A Solar Panel Power Point Tracker" is a very simple MPPT. It regulates the "input voltage" from the solar panels to an approximation of the maximum-power point, very similar to a switching regulator regulating the "output voltage".
 * "Current flow priorities in PSU / PSU review" discusses solar MPPT.
 * Wikipedia: solar inverter


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