S4w's Wind Generator Notes

Ok, as I said before I materialized my data logger board that mates with my MPPT controller via the SPI port.

It logs data to an SD Card and the data can be extracted by reading the SD card in a computer or by connecting the data logger to a PC using the USB port.

So far it is logging great but I still have a few rough edges to chip out. I will do so when I get more time. I need to log input voltage and current.

Here are some pics:

Front:

Back:

Ok, here is a picture of my MPPT fully populated:

During this month I have been able to program into it the following features:

Inductors

To begin this series of tutorials we must deeply understand how inductors work since they are the most important part in a DC-DC converter together with the switches and proper layout.

What are inductors?

Inductors are nothing more than energy storage devices just like capacitors. The difference between them is simply the way they store the energy. Inductance is measured in Henries. Inductors store energy in the form of a magnetic field and the amount of energy (in joules) stored in an inductor is given by:

Well, Ive been very very busy with my electronics projects particularly with the sine wave inverter. I made many changes to it since I presented the schematics.

One important change that I made was the use of IGBTs instead of MOSFETS. IGBTs provide a much more robust inverter because we are dealing with high voltages. They are made to be tough and have much lower junction to case thermal resistance which helps a lot with the cooling.

When one is building an alternator for a windmill there is always a compromise that must be made in order to get the desired results. One of the most important decisions that one must make is to choose a suitable cut-in speed for the propeller that is going to be used.

To recap a little bit Ill briefly explain how the sine wave inverter works. Basically this inverter is a Class D audio power amplifier designed to work with high voltages. The inverter creates a square wave suitable for MOSFET switching with minimal power loss as heat because the MOSFETs will not be in the linear region. There is an on-board sine wave generator that is used as the input signal to the “amplifier”. After filtering out the high frequency square wave, the amplified input signal generated by the on-board oscillator remains.

The clear winner of the last poll was the fourth option. Most visitors would like to see kits to build either a Boost converter for windmill, a buck converter or a charge controller.

I am working on all of them in parallel at this moment. I would like to have a few suggestions about which one visitors would like to see available first. I have no preference what so ever so its your choice world.

As usual I will have the schematics of the kits available to the public.

Happy voting.

Ok, here are the tests for my boost converter. First of all I will clarify that it is running at 100kHz and the output diode is a fast diode with forward voltage drop of 0.7V. I started using a 14uH inductor thinking that it would be the right value for the input voltage range expected, but it turned not to be the case.

NOTE: Click on the image for a larger view