Fortsätt till huvudinnehåll

[VAWT] First practical tests

The first practical tests have commenced! The windmill below is built within this Bachelors Thesis: 

We had worked in small subgroups, where I had focused on calculations, software and electronics. Some other guys had done the mechanical design and therefore I didnt't see the turbine first until the day all parts were to be assembled. What I hadn't realised before is that the turbine is huge! It measures some above 3 meter in height. Here is a rather crappy first movie of over first test run:

 Turbine control is done via electronic switching by using PWM. A Maximum Power Point tracking algorithm is tried here. Among other things wind and electrical output (voltage and current) are measured that can be used to evaluate system performance. This can be used for estimating turbine output.

The current measurement was bit of a challenge to design as it had to work over the unusually large range 0,5- 60 amps. The measurement is split up in to ranges in hardware in this design. Here is what the designed circuit looks like from below:

For simplier interfacing I created a graphic interace using Qt C++. It uses serial communication (UART) and a self designed protocol for changing parameters during runtime, interfacing with the SD-log on the control unit, read strings sent via UART and live plot of values.  When a bluetTooth serial modem is used this can be done wireless which is very neat.  The interface looks something like this:

I choose to call it SavoniusView.


Populära inlägg i den här bloggen

[VAWT] Plausible improvements of the Savonius windmill

Cut a barrel in half, mount it on a shaft and you have a windturbine. If the barrel is used, then what else probably would end up on a scrap heap is instead used for converting renewable energy.

Simplicity and low cost makes this an attractive option especially for societies with limited economy and a malfunctioning or non existing electric grid. Small off-grid electrical networks can be built and people who perhaps most needs electricity get that. Isn't that neat?

Savonius (from

An overlooked potential?
The Savonius though has a widespread reputation of having low effiency and is often dismissed as a credible option around forums and in formal litterature. However, when looking at the graph below from a publication Wortman did 1983, the effiency can be realtively high provided that the TSR(Tip-to-Wind-Speed-Ratio) is held at a correct value and the windmill should work quite nicely. In practice this could probably be done by controlling the generato…

[VAWT] Affordable wind measurements

The shop Clas Ohlsson in Sweden sells a spare anemometer for the  WH-1080 weather station for a hobbyist friendly price around 15 euros. This anemometer can probably be found in other countries too.

The WH-1080 spare anemometer

Here  you can read about how to use this anemometer together with an Arduino or any other embedded system.  As we couldn't find any data on the characteristics of this sensor, we did our own calibration in a wind tunnel and the results are presented in the report above. This anemometer was used in a Bachelors Thesis project related to the devlopment of optimization of the Savonius Turbine, here tagged [VAWT].

[Cubex] First corner balancing of Cubli based hardware

You shouldn't judge a book by a cover they say, and likewise you shouldn't judge a project by what just meets the eye. During our current master thesis work I had the chance to get better acquainted with some of the works of among others Leonhard Euler and Joseph-Louis  Lagrange. These people spent thousands of hours on things that have been  beneficial to even the whole human race. Few people know this though.Why? Because the works consist of truckloads of books full of equations, and it is not as easy to see the use of this as for instance painting a wall or something that is easily recognized and valued. 

This stands in contrast to Cubli. It makes use of abstract science in a way that is perceivable more easily. Although it is a great deal of fun to use the results of among others Euler and Lagrange for various things  it is useful to also demonstrate the concrete use and validity of it for ourselves and others. Therefore we choose to do our master thesis around a Cubli base…